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Wave Glider provides gateway to remote exploration

November 10, 2020

WHOI geochemist Chris German pairs an autonomous surface vehicle (ASV) called a Wave Glider with other vehicles to expand research here and on other Ocean Worlds

Mining ancient dust from the ocean’s loneliest spot

September 24, 2020

Researchers investigate dust from the ocean’s farthest point from land to reconstruct the climactic history of the Southern Hemisphere, and understand how micronutrients have influenced biological productivity in this oceanic desert.

Working from Home: Mallory Ringham

July 2, 2020

WHOI-MIT joint program student outfits her basement to do vital work on a marine carbon sensor

oil spill

A dangerous leak of diesel fuel in the Arctic

June 18, 2020
plastics by the numbers

The many lifetimes of plastics

June 15, 2020

Infographics strive to give us a sense of how long plastic goods will last in the environment. But is this information reliable? The findings of a new study from WHOI may surprise you.

toxins story

Are natural toxins in fish harmful?

May 28, 2020

Marine life has been naturally producing toxic chemicals well before chemical companies were manufacturing PCBs. But are these naturally-produced compounds as harmful as man-made environmental pollutants, and do those pose a human health threat?

Working from Home: Matt Long

May 7, 2020

A marine chemist spends his time at home tinkering on a high-tech buoy in the basement, proving that being homebound doesn’t mean you can’t think big.

Our Radioactive Ocean: Ken Buesseler

April 30, 2020

Ken Buesseler joins the hosts of Future Hindsight Podcast to talk about the safety of the Pacific Ocean, the natural occurrence of radioactivity in our environment, and a citizen scientist project for oceanic testing.

Why Sunlight Matters for Marine Oil Spills

April 30, 2020

A decade of research since the Deepwater Horizon disaster has revealed how sunlight—its importance long understated in oil spill science—substantially alters petroleum floating at the sea surface.

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Finding medical answers in the ocean

March 19, 2020

The test being used to diagnose the novel coronavirus—and other pandemics like AIDS and SARS—was developed with the help of an enzyme isolated from a microbe found in marine hydrothermal vents as well as freshwater hot springs.

News Releases

Climate Change Can Destabilize the Global Soil Carbon Reservoir, New Study Finds

March 23, 2021

The vast reservoir of carbon that is stored in soils probably is more sensitive to destabilization from climate change than has previously been assumed, according to a new study by researchers at WHOI and other institutions.

The study found that the biospheric carbon turnover within river basins is vulnerable to future temperature and precipitation perturbations from a changing climate.

Although many earlier, and fairly localized, studies have hinted at soil organic carbon sensitivity to climate change, the new research sampled 36 rivers from around the globe and provides evidence of sensitivity at a global scale.

“The study results indicate that at the large ecosystem scale of river basins, soil carbon is sensitive to climate variability,” said WHOI researcher Timothy Eglinton, co-lead author of the paper in the Proceedings of the National Academy of Sciences of the United States of America. “This means that changing climate, and particularly increasing temperature and an invigorated hydrological cycle, may have a positive feedback in terms of returning carbon to the atmosphere from previously stabilized pools of carbon in soils.”

The public is generally aware that climate change can potentially destabilize and release permafrost carbon into the atmosphere and exacerbate global warming. But the study shows that this is true for the entire soil carbon reservoir, said WHOI researcher Valier Galy, the other co-lead author of the study.

The soil carbon reservoir is a key component in keeping the atmosphere in check in terms of how much carbon dioxide is in the air. The amount of carbon stored in terrestrial vegetation and soils is three times more than how much the atmosphere holds, and it consumes more than a third of the anthropogenic carbon that is emitted to the atmosphere.

To determine the sensitivity of terrestrial carbon to destabilization from climate change, researchers measured the radiocarbon age of some specific organic compounds from the mouths of a diverse set of rivers. Those rivers—including the Amazon, Ganges, Yangtze, Congo, Danube, and Mississippi—account for a large fraction of the global discharge of water, sediments and carbon from rivers to the oceans.

Terrestrial carbon, however, is not so simple to isolate and measure. That’s because carbon in rivers comes from a variety of sources, including rocks, organic contaminants such as domestic sewage or petroleum that differ widely in their age, and vegetation. To determine what’s happening within the rivers’ watersheds, and to measure radiocarbon from the terrestrial biosphere, researchers focused on two groups of compounds: the waxes of plant leaves that serve a protective function for the plants’ leaf surface and lignin, which is the woody “scaffolding” of land plants.

Taking these measurements showed a relationship between the age of the terrestrial carbon in the rivers and the latitude where the rivers reside, researchers found. That latitudinal relationship prompted researchers to infer that climate must be a key control in the age of the carbon that is exported from the terrestrial biosphere to these rivers, and that temperature and precipitation are primary controls on the age of that carbon.

“Why this study is powerful is because this large number of rivers, the wide coverage, and the wide range of catchment properties give a very clear picture of what’s happening at the global scale,” said Galy.  “You could imagine that by going after lots of rivers, we would have ended up with a very complicated story. However, as we kept adding new river systems to the study, the story was fairly consistent.”

“In many respects, Earth scientists see rivers as being a source signal that is sent to sedimentary records that we can interpret,” said Eglinton. “By going to sedimentary records, we have the opportunity to look at how the terrestrial biosphere has responded to climate variability in the past. In addition, by monitoring rivers in the present day, we can also use them as sentinels in order to assess how these watersheds may be changing.”

New observation network will provide unprecedented, long-term view of life in the ocean twilight zone

February 8, 2021

The ocean twilight zone, a dimly lit region roughly 200–1000 meters (650–3200 feet) below the surface, contains the largest amount of fish biomass on Earth—yet it remains largely unexplored by scientists. A new observation network under development by the Woods Hole Oceanographic Institution (WHOI) seeks to change that. Encompassing 250,000 square kilometers (roughly 155,300 square miles) of the northwest Atlantic Ocean, the network will collect around-the-clock data about the twilight zone over months or even years, offering unprecedented insight into this little-known, yet vitally important region of the sea.

“It will cover a really huge piece of the ocean,” says WHOI ocean ecologist Simon Thorrold, a Principal Investigator for the network. “We’re used to going out for several weeks on a research vessel to study just a small area, and returning there maybe once or twice a year if we’re lucky,” Thorrold says. “Now, we’ll be able to get continuous measurements from a large chunk of the ocean twilight zone over significant periods of time. It’s very exciting.”

The network will give scientists a comprehensive view of the twilight zone, or mesopelagic, using several different technologies including moored buoys equipped with acoustic survey systems; a swarm of optical and geochemical sensors; and new fish-tracking tags that will continuously record the position of major predators such as sharks and tuna. All of these components will connect to the network’s buoys using acoustic signals underwater and an Iridium satellite link at the surface.

The information provided by the network will improve estimates of the density and distribution of fish and invertebrates in the twilight zone, reveal new insights about their interactions and daily migrations to and from the surface—and help fuel new strategies for conservation and policy making. The network will also help researchers better understand how the twilight zone affects carbon cycling and global climate, says WHOI marine radiochemist Ken Buesseler.

“Plankton—tiny plant-like organisms—at the surface remove carbon dioxide from the atmosphere as they grow,” Buesseler says. “When animals from the twilight zone migrate up to feed on those plankton and then return back to deeper waters, they take that carbon with them. The question is, how much does that natural cycle of life and death affect the amount of carbon that is sequestered in the deep ocean? And if humans start removing large numbers of fish from the twilight zone, how could that change?”

Buesseler compares the new observation network to a “field of dreams.”

“You build something like it, and all kinds of researchers will come and use it, because they’ve just never had the opportunity or infrastructure in place for them to be able to do these sorts of observations,” Buesseler says.

Also collaborating on the project are WHOI scientists Andone Lavery and Dana Yoerger, and Melissa Omond from the University of Rhode Island.

Former WHOI President and Director Mark Abbott says it would be challenging to fund this kind of multidisciplinary, large-scale, long-term marine infrastructure through federal sources. Abbott was instrumental in planning the observation network during his tenure. Instead of going through traditional funding channels, he turned to German philanthropist Otto Happel, whose interest in WHOI’s work in the ocean twilight zone led to a generous gift from the Happel Foundation.

“I think what’s really exciting about Otto is his deep appreciation and understanding and curiosity about the science, the engineering, and how this informs ocean policy,” Abbott says. “He’s concerned about all the changes we’re seeing in the marine environment, and he wants to fund work that enables people to make better decisions about the ocean.”

The Happel Foundation’s support will enable WHOI’s ocean twilight zone research team to turn their plans for an observation network into a reality. Work is already underway on sensors and other network components.

“The ocean always has been my passion, in many respects,” Happel says. “I’m thrilled that with a relatively small amount of funding, we can start to answer questions about it that may be vital to changing how we operate and how we live in this world.”

The Woods Hole Oceanographic Institution (WHOI) is a private, non-profit organization on Cape Cod, Massachusetts, dedicated to marine research, engineering, and higher education. Established in 1930, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate an understanding of the ocean’s role in the changing global environment. WHOI’s pioneering discoveries stem from an ideal combination of science and engineering—one that has made it one of the most trusted and technically advanced leaders in basic and applied ocean research and exploration anywhere. WHOI is known for its multidisciplinary approach, superior ship operations, and unparalleled deep-sea robotics capabilities. We play a leading role in ocean observation, and operate the most extensive suite of data-gathering platforms in the world. Top scientists, engineers, and students collaborate on more than 800 concurrent projects worldwide—both above and below the waves—pushing the boundaries of knowledge and possibility. For more information, please visit www.whoi.edu

 

New study takes comprehensive look at marine pollution

December 3, 2020

Paper finds ocean pollution is a complex mix of chemicals and materials, primarily land-based in origin, with far-reaching consequences for environmental and human health, but there are options available for world leaders

 

For centuries, the ocean has been viewed as an inexhaustible receptacle for the byproducts of human activity. Today, marine pollution is widespread and getting worse and, in most countries, poorly controlled with the vast majority of contaminants coming from land-based sources. That’s the conclusion of a new study by an international coalition of scientists taking a hard look at the sources, spread, and impacts of ocean pollution worldwide.

The study is the first comprehensive examination of the impacts of ocean pollution on human health. It was published December 3 in the online edition of the Annals of Global Health and released the same day at the Monaco International Symposium on Human Health & the Ocean in a Changing World, convened in Monaco and online by the Prince Albert II de Monaco Foundation, the Centre Scientifique de Monaco and Boston College.

“This paper is part of a global effort to address questions related to oceans and human health,” said Woods Hole Oceanographic Institution (WHOI) toxicologist and senior scientist John Stegeman who is second author on the paper. “Concern is beginning to bubble up in a way that resembles a pot on the stove. It’s reaching the boiling point where action will follow where it’s so clearly needed.”

Despite the ocean’s size—more than two-thirds of the planet is covered by water—and fundamental importance supporting life on Earth, it is under threat, primarily and paradoxically from human activity. The paper, which draws on 584 peer-reviewed scientific studies and independent reports, examines six major contaminants: plastic waste, oil spills, mercury, manufactured chemicals, pesticides, and nutrients, as well as biological threats including harmful algal blooms and human pathogens.

It finds that ocean chemical pollution is a complex mix of substances, more than 80% of which arises from land-based sources. These contaminants reach the oceans through rivers, surface runoff, atmospheric deposition, and direct discharges and are often heaviest near the coasts and most highly concentrated along the coasts of low- and middle-income countries. Waters most seriously impacted by ocean pollution include the Mediterranean Sea, the Baltic Sea, and Asian rivers. For the many ocean-based ecosystems on which humans rely, these impacts are exacerbated by global climate change. According to the researchers, all of this has led to a worldwide human health impacts that fall disproportionately on vulnerable populations in the Global South, making it a planetary environmental justice problem, as well.

In addition to Stegeman, who is also director of the NSF- and NIH-funded Woods Hole Center for Oceans and Human Health, WHOIbiologists Donald Anderson and Mark Hahn, and chemist Chris Reddy also contributed to the report. Stegeman and the rest of the WHOI team worked on the analysis with researchers from Boston College’s Global Observatory on Pollution and Health, directed by the study’s lead author and Professor of Biology Philip J. Landrigan, MD. Anderson led the report’s section on harmful algal blooms, Hahn contributed to a section on persistent organic pollutants (POPs) with Stegeman, and Reddy led the section on oil spills. The Observatory, which tracks efforts to control pollution and prevent pollution-related diseases that account for 9 million deaths worldwide each year, is a program of the new Schiller Institute for Integrated Science and Society, part of a $300-million investment in the sciences at BC. Altogether, over 40 researchers from institutions across the United States, Europe and Africa were involved in the report.

In an introduction printed in Annals of Global Health, Prince Albert of Monaco points out that their analysis, in addition to providing a global wake-up, serves as a call to mobilize global resolve to curb ocean pollution and to mount even greater scientific efforts to better understand its causes, impacts, and cures.

“The link between ocean pollution and human health has, for a long time, given rise to very few studies,” he says. “Taking into account the effects of ocean pollution—due to plastic, water and industrial waste, chemicals, hydrocarbons, to name a few—on human health should mean that this threat must be permanently included in the international scientific activity.”

The report concludes with a series of urgent recommendations. It calls for eliminating coal combustion, banning all uses of mercury, banning single-use plastics, controlling coastal discharges, and reducing applications of chemical pesticides and fertilizers. It argues that national, regional and international marine pollution control programs must extend to all countries and where necessary supported by the international community. It calls for robust monitoring of all forms of ocean pollution, including satellite monitoring and autonomous drones. It also appeals for the formation of large, new marine protected areas that safeguard critical ecosystems, protect vulnerable fish stocks, and ultimately enhance human health and well-being.

Most urgently, the report calls upon world leaders to recognize the near-existential threats posed by ocean pollution, acknowledge its growing dangers to human and planetary health, and take bold, evidence-based action to stop ocean pollution at its source.

“The key thing to realize about ocean pollution is that, like all forms of pollution, it can be prevented using laws, policies, technology, and enforcement actions that target the most important pollution sources,” said Professor Philip Landrigan, MD, lead author and Director of the Global Observatory on Pollution on Health and of the Global Public Health and the Common Good Program at Boston College. “Many countries have used these tools and have successfully cleaned fouled harbors, rejuvenated estuaries, and restored coral reefs. The results have been increased tourism, restored fisheries, improved human health, and economic growth. These benefits will last for centuries.”

The report is being released in tandem with the Declaration of Monaco: Advancing Human Health & Well-Being by Preventing Ocean Pollution, which was read at the symposium’s closing session. Endorsed by the scientists, physicians and global stakeholders who participated in the symposium in-person and virtually, the declaration summarizes the key findings and conclusions of the Monaco Commission on Human Health and Ocean Pollution. Based on the recognition that all life on Earth depends on the health of the seas, the authors call on leaders and citizens of all nations to “safeguard human health and preserve our Common Home by acting now to end pollution of the ocean.”

“This paper is a clarion call for all of us to pay renewed attention to the ocean that supports life on Earth and to follow the directions laid out by strong science and a committed group of scientists,” said Rick Murray, WHOI Deputy Director and Vice President for research and a member of the conference steering committee. “The ocean has sustained humanity throughout the course of our evolution—it’s time to return the favor and do what is necessary to prevent further, needless damage to our life planetary support system.”

Funding for this work was provided in part by the U.S. Oceans and Human Health Program (NIH grant P01ES028938 and National Science Foundation grant OCE-1840381), the Centre Scientifique de Monaco, the Prince Albert II of Monaco Foundation, the Government of the Principality of Monaco, and Boston College.

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The Woods Hole Oceanographic Institution (WHOI) is a private, non-profit organization on Cape Cod, Massachusetts, dedicated to marine research, engineering, and higher education. Established in 1930, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate an understanding of the ocean’s role in the changing global environment. WHOI’s pioneering discoveries stem from an ideal combination of science and engineering—one that has made it one of the most trusted and technically advanced leaders in basic and applied ocean research and exploration anywhere. WHOI is known for its multidisciplinary approach, superior ship operations, and unparalleled deep-sea robotics capabilities. We play a leading role in ocean observation, and operate the most extensive suite of data-gathering platforms in the world. Top scientists, engineers, and students collaborate on more than 800 concurrent projects worldwide—both above and below the waves—pushing the boundaries of knowledge and possibility. For more information, please visit www.whoi.edu

 

First Detailed Oil Sample Analysis Completed from Mauritius Oil Spill

October 29, 2020

When the Japanese bulk carrier MV Wakashio struck a coral reef off the coast of Mauritius on July 25, 2020, and began leaking fuel oil two weeks later, local residents and the international community sprang into action to protect the pristine habitats that fringe the Indian Ocean nation. But they did so without insight from careful chemical analysis, which is customary after spills to help guide short and long-term response plans and protects the health of people facing such a spill.

Now the first ultra-high-resolution analysis of an oil sample from Mauritius shows that the material is a complex and unusual mix of hydrocarbons—and even though some of the components in it may have already degraded or evaporated, what remains still gives it the ability to persist in the environment. That is the conclusion of marine oil spill experts Chris Reddy and Bob Nelson at the Woods Hole Oceanographic Institution (WHOI), who are collaborating with Professor Kliti Grice, Director of the Western Australian Organic Isotope Geochemistry Centre (WA-OIGC) and Associate Professor Monique Gagnon and Alan Scarlett at Curtin University in Perth, Australia. Both teams analyzed a sample of floating residue collected August 16.  They subjected it to many of the same analytical techniques used to “fingerprint” samples from other large spills around the world.

The two teams use comprehensive two-dimensional gas chromatography (GC×GC), complemented by compound-specific isotope analyses to identify compounds specific to spilled oils. The analyses performed by the two laboratories provide some of the most highly advanced analytical services and scientific support to oil spill responders. They found their results were consistent with what they would expect from a sample of fuel oil, which is a non-standardized mix of petroleum products that ships often use to run their engines. In recent years, calls to improve air quality around ports has driven the industry to adopt new low-sulfur formulations that reduce emissions. At the same time, however, the potential is rising for spills of this type, but the scientific community has yet to see what happens to these new low-sulfur fuels when they enter the environment.

Key Takeaways

  • Marine oil spill experts from Woods Hole Oceanographic Institution recently provided one of the first detailed oil sample analysis from the July 25 Mauritius oil spill.
  • WHOI worked with experts from the Western Australian Organic Isotope Geochemistry Centre (WA-OIGC) and Curtin University in Perth, Australia.
  • Their analysis shows that the material is a complex and unusual mix of hydrocarbons.
  • This type of analysis is the gold standard in oil spills—it’s not only used to fingerprint the oil, but also to positively identify the constituent parts of an oil to figure out how to best fight a spill and guide short and long-term response plans while protecting the health of people facing such a spill.

A comprehensive two-dimensional gas chromatography (GCxGC) of the fuel oil collected in Mauritius after the wreck of the ship Wakashio reveals (A) a relatively low ratio of aromatic hydrocarbons relative to saturated hydrocarbons, likely a result of the de-sulfurization process the fuel underwent; and (B) a high concentration of secohopanes compared to hopanes, which can be used to help “fingerprint” the sample and potentially identify the source of future samples. (Image by Bob Nelson, ©Woods Hole Oceanographic Institution) A comprehensive two-dimensional gas chromatography (GCxGC) of the fuel oil collected in Mauritius after the wreck of the ship Wakashio reveals (A) a relatively low ratio of aromatic hydrocarbons relative to saturated hydrocarbons, likely a result of the de-sulfurization process the fuel underwent; and (B) a high concentration of secohopanes compared to hopanes, which can be used to help “fingerprint” the sample and potentially identify the source of future samples. (Image by Bob Nelson, ©Woods Hole Oceanographic Institution)

“Fuel oils, are arguably the most challenging petroleum products to analyze and investigate following marine-based spills,” said Reddy. “There is no single recipe or set of ingredients, and it gets even more complicated with these new low-sulfur fuel oils that require more steps in their manufacture. We don’t know if this was a low-sulfur material, but it’s unlike anything we’ve seen spilled before—that alone demands a closer look.”

Analysis by WA-OIGC at Curtin and also confirmed by WHOI’s Organic Geochemistry Analysis Lab showed that the sample contained relatively low levels of polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens in humans and animals. Although low, the levels of PAHs might accumulate in certain parts of the marine environment. In addition, Reddy found a relatively high concentration and variety of secohopanes and surprisingly low levels of hopanes, both of which are “biomarkers” that will help connect future samples of oil to the Wakashio ship. These substances were present in minute amounts, but still detectable thanks to the technology available in the collaborating laboratories. Only comparison to a “fresh” sample taken from the ship would allow researchers to determine what has already been lost from the oil as a result of evaporation, dilution, photodegradation, and other effects.

“This was just a first step,” said Grice. “Our limited view of what spilled only reinforces the need for long-term monitoring, access to samples from the ship, and a more in-depth analysis that officials can incorporate into detailed plans to help Mauritius and its environment recover from this.”

The sample was acquired by Associate Professor Monique Gagnon at Curtin University. If members of the public have photos of oil and oiled material or other information, including photos of unoiled beaches and reefs, that might help Reddy and Grice and their research teams better understand the nature of the spill, they are welcome to email oilsamples@whoi.edu.

The Woods Hole Oceanographic Institution (WHOI) is a private, non-profit organization on Cape Cod, Massachusetts, dedicated to marine research, engineering, and higher education. Established in 1930, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate an understanding of the ocean’s role in the changing global environment. WHOI’s pioneering discoveries stem from an ideal combination of science and engineering—one that has made it one of the most trusted and technically advanced leaders in basic and applied ocean research and exploration anywhere. WHOI is known for its multidisciplinary approach, superior ship operations, and unparalleled deep-sea robotics capabilities. We play a leading role in ocean observation, and operate the most extensive suite of data-gathering platforms in the world. Top scientists, engineers, and students collaborate on more than 800 concurrent projects worldwide—both above and below the waves—pushing the boundaries of knowledge and possibility. For more information, please visit www.whoi.edu

 

New multi-institutional grant will support a fleet of robotic floats

October 29, 2020

On October 29, 2020, the National Science Foundation approved a $53 million grant to a consortium of the country’s top ocean-research institutions to build a global network of chemical and biological sensors that will monitor ocean health. Scientists at the Monterey Bay Aquarium Research Institute (MBARI), Woods Hole Oceanographic Institution (WHOI), University of Washington, Scripps Institution of Oceanography, and Princeton University will use this grant to build and deploy 500 robotic ocean-monitoring floats around the globe.

This new network of floats, called the Global Ocean Biogeochemistry Array (GO-BGC Array), will collect observations of ocean chemistry and biology between the surface and a depth of 2,000 meters (6,562 feet). Data streaming from the float array will be made freely available within a day of being collected, and will be used by scores of researchers, educators, and policy makers around the world.

These data will allow scientists to pursue fundamental questions about ocean ecosystems, observe ecosystem health and productivity, and monitor the elemental cycles of carbon, oxygen, and nitrogen in the ocean through all seasons of the year. Such essential data are needed to improve computer models of ocean fisheries and climate, and to monitor and forecast the effects of ocean warming and ocean acidification on sea life.

Although scientists can use Earth-orbiting platforms and research vessels to monitor the ocean, satellites can only monitor near-surface waters, and the small global fleet of open-ocean research ships can only remain at sea for relatively short periods of time. As a result, ocean-health observations only cover a tiny fraction of the ocean at any given time, leaving huge ocean regions unvisited for decades or longer.

A single robotic float costs the same as two days at sea on a research ship. But floats can collect data autonomously for over five years, in all seasons, including during winter storms, when shipboard work is limited.

Funding for the GO-BGC Array is provided through the NSF’s Mid-scale Research Infrastructure-2 Program (MSRI-2). The GO-BGC Array is the National Science Foundation’s contribution to the Biogeochemical-Argo (BGC-Argo) project. It extends biological and chemical observing globally, and builds on two ongoing efforts to monitor the ocean using robotic floats, both of which have been highly successful.

The first of these programs, the Argo array, consists of 3,900 robotic floats that drift through the deep ocean basins, providing information on temperature and salinity in the water column. Since its inception in 1999, Argo data have been used in 4,100 scientific papers. As the first global, subsurface ocean observing system, the Argo array has done an incredible job of measuring the physical properties of our ocean, but Argo floats do not provide information about the ocean’s vital chemical and biological activity.

Starting in 2014, the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program deployed a large array of robotic “biogeochemical” floats, based on the Argo design, but carrying sensors to monitor the chemical and biological properties of the ocean. SOCCOM floats have operated for nearly six years in the remote, stormy, and often ice-covered Southern Ocean—arguably one of the harshest marine environments on Earth. These floats have already provided critical new information about how the Southern Ocean interacts with the Earth’s atmosphere and winter sea ice.

Similar to the SOCCOM floats, the new GO-BGC floats will carry a number of sensors in addition to the core Argo sensors for temperature, depth, and salinity. These include instruments to measure oxygen concentration, pH (ocean acidity), nitrate (an essential nutrient for microscopic algae), sunlight (required for algal growth), chlorophyll (an indicator of algal populations), and particles in the water (including microscopic algae). Over the last few years, researchers have been testing, refining, and calibrating these sensitive instruments as part of the SOCCOM program and other international efforts.

The instruments on these floats will allow researchers to monitor the health of the ocean, including the growth and respiration of phytoplankton (drifting algae and microbes that use sunlight as a source of energy) and the nutrients and light that control these processes. In addition to supporting most of life in the ocean, including commercial fisheries, phytoplankton supply oxygen to and remove carbon dioxide from the ocean and the atmosphere. These microscopic plankton have huge impacts on our climate through their control on carbon dioxide. The new floats will also provide first-hand data on long-term changes in the ocean, including ocean acidification and the expansion of low-oxygen zones.

This five-year effort involves five research institutions. MBARI will coordinate the project, refine the sensors, take the lead in processing data from the floats, and perform outreach for the program. WHOI, the University of Washington, and the Scripps Institution of Oceanography,  will build and deploy floats in collaboration with commercial partners. Researchers at Princeton University will contribute to the array design and project management, and ensure that the data are linked to global computer models of the Earth’s ocean and climate. This program will also have a significant impact on the ocean technology industry, including a number of commercial suppliers of ocean sensors and profiling floats.

A broad public-outreach program, including workshops, web-based curricula, and hands-on activities, will help scientists, teachers, students, and others use these data. In an expansion of the existing SOCCOM Adopt-A-Float program, the floats will be adopted by elementary- to college-level classes. Student activities will be developed through a partnership with the national Marine Advanced Technology Education program. In addition, courses based on GO-BGC technology will be offered through the The Sandbox, a makerspace at the Scripps Institution of Oceanography.

The researchers hope that GO-BGC will inspire other countries to contribute similarly instrumented floats, as part of the new global biogeochemical ARGO effort. Ideally, this expanded network would grow to a sustained array of 1,000 biogeochemical floats uniformly distributed around the world ocean, and spaced about 1,000 kilometers (620 miles) apart.

“Vast swaths of the Atlantic remain unmonitored with respect to ocean health, except for sporadic, infrequent research ship visits and widely spaced moored instruments,” added Susan Wijffels, WHOI senior scientist and co-principal investigator of GO-BCG. “Based on what we know about the Atlantic’s critical role in Earth’s climate and other key planetary systems, we need to fill in those gaps.”

“The GO-BGC Array will provide the scientific community with the unprecedented ability to take the pulse of ocean ecosystems and monitor the health of underlying chemical cycles on a global scale,” said David “Roo” Nicholson, WHOI associate scientist and co-lead of GO-BCG at WHOI. “Such observations are critical to understanding how the ocean will respond to multiple, broad-scale stressors such as warming, acidification, and deoxygenation.”

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit www.whoi.edu.

Key Takeaways

  • A five-year, $53 million grant from the National Science Foundation to a consortium of ocean-research institutions will build a global network of 500 robotic biochemical sensors.
  • The GO-BGC (Global Ocean Biogeochemistry) Array will be led by the Monterey Bay Aquarium Research Institute and include WHOI, the University of Washington, Scripps Institution of Oceanography, and Princeton University.
  • The array will measure critical indicators of ocean health, including temperature, salinity, oxygen concentration, pH, nitrate concentration, chlorophyll, and light levels from the surface to 2,000 meters depth.
  • WHOI’s role will focus on the construction and deployment of floats in the Atlantic Ocean with academic and commercial partners.
SOCCOM float The GO-BGC array will be based on floats used in the SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) project like the one here being deployed in 2016. (Image courtesy of SOCCOM. SOCCOM is supported by the National Science Foundation under NSF Award PLR-1425989 and OPP-1936222) WHOI engineer Bill Dullea with one of the autonomous profiling floats that WHOI will help deploy in the Atlantic Ocean as part of the GO-BGC Array. (Photo by Ken Kostel, ©Woods Hole Oceanographic Institution) WHOI engineer Bill Dullea with one of the autonomous profiling floats that WHOI will help deploy in the Atlantic Ocean as part of the GO-BGC Array. (Photo by Ken Kostel, ©Woods Hole Oceanographic Institution) Illustration showing the operation of a typical Argo profiling float. (Image by Kim Fulton-Bennett, © 2020 MBARI) Illustration showing the operation of a typical Argo profiling float. (Image by Kim Fulton-Bennett, © 2020 MBARI) Configuration of a GO-BGC autonomous profiling float. (Illustration by Kelly Lance, © 2020 MBARI)

Configuration of a GO-BGC autonomous profiling float. (Illustration by Kelly Lance, ©2020 MBARI)

Additional Information

GO-BGC Array website

Wijffels

Susan Wijffels

Nicholson_David-e1532392918773-320x366

David “Roo” Nicholson

Porites coral

Ocean acidification causing coral ‘osteoporosis’ on iconic reefs

August 27, 2020

Scientists have long suspected that ocean acidification is affecting corals’ ability to build their skeletons, but it has been challenging to isolate its effect from that of simultaneous warming ocean temperatures, which also influence coral growth. New research from the Woods Hole Oceanographic Institution (WHOI) reveals the distinct impact that ocean acidification is having on coral growth on some of the world’s iconic reefs.

In a paper published Aug. 27, 2020, in the journal Geophysical Research Letters, researchers show a significant reduction in the density of coral skeleton along much of the Great Barrier Reef—the world’s largest coral reef system—and also on two reefs in the South China Sea, which they attribute largely to the increasing acidity of the waters surrounding these reefs since 1950.

“This is the first unambiguous detection and attribution of ocean acidification’s impact on coral growth,” says lead author and WHOI scientist Weifu Guo. “Our study presents strong evidence that 20th century ocean acidification, exacerbated by reef biogeochemical processes, had measurable effects on the growth of a keystone reef-building coral species across the Great Barrier Reef and in the South China Sea. These effects will likely accelerate as ocean acidification progresses over the next several decades.”

Roughly a third of global carbon dioxide emissions are absorbed by the ocean, causing an average 0.1 unit decline in seawater pH since the pre-industrial era. This phenomenon, known as ocean acidification, has led to a 20 percent decrease in the concentration of carbonate ions in seawater. Animals that rely on calcium carbonate to create their skeletons, such as corals, are at risk as ocean pH continues to decline. Ocean acidification targets the density of the skeleton, silently whittling away at the coral’s strength, much like osteoporosis weakens bones in humans.

“The corals aren’t able to tell us what they’re feeling, but we can see it in their skeletons,” said Anne Cohen, a WHOI scientist and co-author of the study. “The problem is that corals really need the strength they get from their density, because that’s what keeps reefs from breaking apart.  The compounding effects of temperature, local stressors, and now ocean acidification will be devastating for many reefs.”

Key Takeaways

  • An innovative numerical model developed by researchers at the Woods Hole Oceanographic Institution demonstrates the distinct impact of ocean acidification—separate from ocean warming—on coral growth.
  • The model shows that ocean acidification has caused a 13 percent decline in the skeletal density of Porites corals in the Great Barrier Reef, and a 7 percent decline in the South China Sea since 1950.
  • Pollution and land runoff can exacerbate the effects of ocean acidification, causing corals in local reefs to weaken more quickly than those located farther away from human settlements.
  • A global-scale investigation of coral CT scans could help to target protections for vulnerable reefs.
MIT-WHOI Joint Program student Nathaniel Mollica (left) and WHOI scientist Weifu Guo examine a core extracted from a coral skeleton. Photo by Anne Cohen Lab, ©Woods Hole Oceanographic Institution MIT-WHOI Joint Program student Nathaniel Mollica (left) and WHOI scientist Weifu Guo examine a core extracted from a coral skeleton. Photo by Anne Cohen Lab, ©Woods Hole Oceanographic Institution

In their investigation, Guo and his co-authors examined published data collected from the skeletons of Porites corals—a long-living, dome-shaped species found across the Indo-Pacific— combined with new three-dimensional CT scan images of Porites from reefs in the central Pacific Ocean. Using these skeletal archives, which date back to 1871, 1901, and 1978, respectively, the researchers established the corals’ annual growth and density. They plugged this information, as well as historical temperature and seawater chemistry data from each reef, into a model to predict the corals’ response to constant and changing environmental conditions.

The authors found that ocean acidification caused a significant decline in Porites skeletal density in the Great Barrier Reef (13 percent) and the South China Sea (7 percent), starting around 1950. Conversely, they found no impact of ocean acidification on the same types of corals in the Phoenix Islands and central Pacific, where the protected reefs are not as impacted by pollution, overfishing, runoff from land.

While carbon dioxide emissions are the largest driver of ocean acidification on a global scale, the authors point out that sewage and runoff from land can exacerbate the effect, causing even further reductions of seawater pH on nearby reefs. The authors attribute the declining skeletal density of corals on the Great Barrier Reef and South China Sea to the combined effects of ocean acidification and runoff. Conversely, reefs in marine protected areas of the central Pacific have so far been shielded from these impacts.

“This method really opens a new way to determine the impact of ocean acidification on reefs around the world,” said Guo. “Then we can focus on the reef systems where we can potentially mitigate the local impacts and protect the reef.”

Co-authors of the paper include Rohit Bokade (Northeastern University), Nathaniel Mollica (MIT-WHOI joint program), and Muriel Leung (University of Pennsylvania), as well as Russell Brainard of King Abdullah University of Science and Technology and formerly at the Coral Reef Ecosystem Division of the Pacific Islands Fisheries Science Center.

Funding for this research was provided by the National Science Foundation, the Robertson Foundation, The Tiffany & Co. Foundation, the Atlantic Donor Advised Fund, and WHOI’s Investment in Science Fund.

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit www.whoi.edu.

New paper addresses the mix of contaminants in Fukushima wastewater

August 6, 2020

Nearly 10 years after the Tohoku-oki earthquake and tsunami devastated Japan’s Fukushima Dai-ichi Nuclear Power Plant and triggered an unprecedented release radioactivity into the ocean, radiation levels have fallen to safe levels in all but the waters closest to the shuttered power plant. Today, fish and other seafood caught in waters beyond all but a limited region have been found to be well within Japan’s strict limits for radioactive contamination, but a new hazard exists and is growing every day in the number of storage tanks on land surrounding the power plant that hold contaminated wastewater. An article published August 7 in the journal Science takes a look at some of the many radioactive elements contained in the tanks and suggests that more needs to be done to understand the potential risks of releasing wastewater from the tanks into the ocean.

“We’ve watched over the past nine-plus years as the levels of radioactive cesium have declined in seawater and in marine life in the Pacific,” said Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institution and author of the new paper. “But there are quite a few radioactive contaminants still in those tanks that we need to think about, some of which that were not seen in large amounts in 2011, but most importantly, they don’t all act the same in the ocean.”

Since 2011, Buesseler has been studying the spread of radiation from Fukushima into and across the Pacific. In June of that year, he mobilized a team of scientists to conduct the first international research cruise to study the early pathways that cesium-134 and -137, two radioactive isotopes of cesium produced in reactors, were taking as they entered the powerful Kuroshio Current off the coast of Japan. He has also built a network of citizen scientists in the U.S. and Canada who have helped monitor the arrival and movement of radioactive material on the Pacific coast of North America.

Now, he is more concerned about the more than 1,000 tanks on the grounds of the power plant filling with ground water and cooling water that have become contaminated through contact with the reactors and their containment buildings. Sophisticated cleaning processes have been able to remove many radioactive isotopes and efforts to divert groundwater flows around the reactors have greatly reduced the amount of contaminated water being collected to less than 200 metric tons per day, but some estimates see the tanks being filled in the near future, leading some Japanese officials to suggest treated water should be released into the ocean to free up space for more wastewater.

One of the radioactive isotopes that remains at the highest levels in the treated water and would be released is tritium, an isotope of hydrogen is almost impossible to remove, as it becomes part of the water molecule itself. However, tritium has a relatively short half-life, which measures the rate of decay of an isotope; is not absorbed as easily by marine life or seafloor sediments, and produces beta particles, which is not as damaging to living tissue as other forms of radiation. Isotopes that remain in the treated wastewater include carbon-14, cobalt-60, and strontium-90. These and the other isotopes that remain, which were only revealed in 2018, all take much longer to decay and have much greater affinities for seafloor sediments and marine organisms like fish, which means they could be potentially hazardous to humans and the environment for much longer and in more complex ways than tritium.

“The current focus on tritium in the wastewater holding tanks ignores the presence other radioactive isotopes in the wastewater,” said Buesseler. “It’s a hard problem, but it’s solvable. The first step is to clean up those additional radioactive contaminants that remain in the tanks, and then make plans based on what remains. Any option that involves ocean releases would need independent groups keeping track of all of the potential contaminants in seawater, the seafloor, and marine life. The health of the ocean—and the livelihoods of countless people—rely on this being done right.”

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit www.whoi.edu.

Key Takeaways

  • Concentrations of radioactive material released into the Pacific from the Fukushima Dai-ichi nuclear power plant and found in the Pacific Ocean or in fish have largely declined to safe levels.
  • A larger problem exists in the form of more than 1,000 tanks full of contaminated, but treated, wastewater stored on the grounds of the power plant and that have been suggested need to be emptied into the ocean to free up space for more untreated water.
  • Current focus on tritium levels overlooks the much larger problem presented by other radioactive isotopes in the treated water, not all of which have been made public.
  • Many of these other isotopes emit more dangerous forms of radiation, and act in more complex ways in the environment, accumulating in seafloor sediments and in marine life, more readily than tritium.

Ken Buesseler

Cafe Thorium

Ocean Topic

Fukushima Radiation

Benjamin Van Mooy

WHOI receives $2.7M from Simons Foundation to study nutrients, microbes that fuel ocean food web

July 23, 2020

The Simons Foundation has awarded Woods Hole Oceanographic Institution (WHOI) scientists Dan Repeta and Benjamin Van Mooy two grants totaling $2.7 million to study key processes that help fuel the health of our ocean and planet.

Repeta’s research will focus on phosphorus, iron and nitrogen, the trinity of nutrients that fuel microbial cycles in the ocean. Van Mooy’s research centers on understanding carbon and energy flow through the microbial food web. His lab uses lipidomics—the comprehensive analysis of a cell or organism’s lipid profile, to learn how ocean microbes harvest, store, and use chemical energy from light. Both research projects are focused on samples and data collected at Station ALOHA—a 6-mile radius circle in the Pacific Ocean north of Hawaii, a hub for oceanographic research projects that is yielding a remarkable collection of observations about Earth’s dynamic oceans and atmosphere.

The Simons Foundation funding will also support research on the inner workings of the mesopelagic zone (aka the twilight zone), a little understood part of the ocean with a major role in sequestering carbon.

Ocean microbes capture solar energy, catalyze biogeochemical transformations of important elements, produce and consume greenhouse gases, and fuel the marine food web. “Microbes sustain all of Earth’s habitats, including its largest biome, the global ocean,” said Marian Carlson, director of life sciences at the Simons Foundation. “It’s critical that we know more about these important processes.”

“We are grateful for the generous support of the Simons Foundation for basic research that is the fundamental underpinning of our knowledge of the ocean, said Richard Murray, WHOI Deputy Director and Vice President for Research. “Understanding elemental ocean processes is the equivalent of understanding the human body’s basic workings. Without this information, we cannot understand, or protect, our ocean’s and planet’s health.”

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit www.whoi.edu.

About the Simons Foundation

The Simons Foundation’s mission is to advance the frontiers of research in mathematics and the basic sciences. We sponsor a range of programs that aim to promote a deeper understanding of our world. For more information, go to www.simonsfoundation.org

WHOI Scientists Make Woods Hole Film Festival Appearance

July 17, 2020

Woods Hole Oceanographic Institution (WHOI) scientists appear in two shorts and a feature film at this year’s Woods Hole Film Festival (WHFF). In addition, scientists will also participate in Q&A sessions connected to three of the festival’s feature-length, ocean-themed entries.

The short films, “Divergent Warmth” and “Beyond the Gulf Stream” are part of a program titled “The Blue Between Us,” offered on-demand from July 25 to August 1 as part of the festival’s virtual program.

In “Divergent Warmth,” producer-director Megan Lubetkin gives viewers a behind-the-scenes look at the synchronized ballet aboard a research vessel during a recent expedition to the East Pacific Rise. Experimental music provides rhythm to imagery of deck operations, launch and recovery of the human-occupied submersible Alvin, and other-worldly views of seafloor hydrothermal vents and lava flows. Interwoven throughout is an evocative reading of Adrienne Rich’s poem, “Diving into the Wreck.”

Dan Fornari, a WHOI emeritus research scholar, acted as associate producer of the 10-minute film. As one of the scientists on the December 2019 expedition, he invited Lubetkin, herself a scientist and the creative exhibits coordinator with the Ocean Exploration Trust, to assist with subsea camera operations and video data management on board. Lubetkin spent her free time shooting additional video, which she edited together while still on the ship to produce a first draft of “Divergent Warmth.”

“I was blown away. It was just fabulous,” Fornari said of his first viewing. “It captures the spirit of going out to sea and being involved in this exploratory effort in the alien realm, where very few people get to go.”

The complex winter currents that collide off the coast of Cape Hatteras are the focus of “Beyond the Gulf Stream,” a short documentary by the Georgia-based production company MADLAWMEDIA. Filmed aboard the WHOI-operated research vessel Neil Armstrong, the 10-minute film features WHOI physical oceanographers Magdalena Andres, Glen Gawarkiewicz, and graduate student Jacob Forsyth as they share their perspectives on the challenges and rewards of doing scientific research at sea, often in difficult conditions.

“I think we have a responsibility to communicate science and the process of doing of science to the public,” said Andres about the film, which was produced in collaboration with WHOI and the Skidaway Institute of Oceanography at the University of Georgia. “It does a really nice job of capturing life at sea in the wintertime.”

As a scientist who uses video to capture data from the ocean depths, Fornari is highly attuned to the impact that visual media can have in capturing the public’s imagination about the ocean.

“These kinds of artistic expressions help open doors to people’s minds.” he said. “That’s crucial for getting the public to understand how critically important the oceans are. Then maybe more students will say, ‘I want to be an ocean scientist when I grow up.’”

In addition to the shorts program itself, WHOI scientists, staff, and students will also participate in “Filmmaker Chats” open to the public and broadcast via Zoom, as well as the WHFF Facebook and YouTube channels. Maddux-Lawrence will take questions about “Beyond the Gulf Stream” on Sunday, July 19, beginning at 9:00 a.m. On Friday, July 31 at 9:00 a.m., Lubetkin will appear with Fornari, as well as Alvin pilot Drew Bewley, MIT-WHOI Joint Program graduate student Lauren Dykman, and Texas A&M graduate student Charlie Holmes II to discuss the making of and science behind “Divergent Warmth.” Recordings of both sessions will also be available for viewing afterward on the festival website.

In addition to the short films, WHOI whale biologist Michael Moore appears in the feature-length documentary “Entangled,” which looks at the intertwined plights of the critically endangered North Atlantic right whale and coastal fishing communities in New England and eastern Canada. After being hunted for centuries, the whales face new challenges in the form of climate change and increased fishing and shipping activity, and Moore has been an outspoken proponent of the need for increased protections to stave off their slide to extinction within the next 20 years.

WHOI scientists will also add their perspective to Q&A sessions following several ocean-themed, feature-length films selected for the festival:

  • Thursday, July 30, at 10:00 p.m.: Research specialist Hauke Kite-Powell will answer questions related to aquaculture and seafood in relation to the film “Fish & Men.
  • Saturday, August 1, from 4:00 to 5:00 p.m.: Marine chemist Chris Reddy will answer questions about microplastics in relation to the film “Microplastics Madness.”
  • Saturday, August 1, from 7:00 to 8:00 p.m.: Marine biologist Simon Thorrold will answer questions about marine protected areas and fishing in connection with the film “Current Sea.”

Key Takeaways

  • Films featuring WHOI scientists will be screened as part of “The Blue Between Us” shorts program at the virtual Woods Hole Film Festival, which may be viewed online by festival passholders and individual ticketholders during the festival, which runs from Saturday, July 25, to Saturday, August 1. Tickets and more information is available here.
  • Whale biologist Michael Moore will appear in the feature-length film “Entangled” about the plight of critically endangered North Atlantic right whales.
  • WHOI scientists will also participate in Q&A sessions associated with several ocean-themed, feature-length festival films.
  • More information is available on the festival website.

What did scientists learn from Deepwater Horizon?

April 20, 2020

Paper reviews major findings, technological advances that could help in next deep-sea spill. 

Ten years ago, a powerful explosion destroyed an oil rig in the Gulf of Mexico, killing 11 workers and injuring 17 others. Over a span of 87 days, the Deepwater Horizon well released an estimated 168 million gallons of oil and 45 million gallons of natural gas into the ocean, making it the largest accidental marine oil spill in history.

Researchers from Woods Hole Oceanographic Institution (WHOI) quickly mobilized to study the unprecedented oil spill, investigating its effects on the seafloor and deep-sea corals and tracking dispersants used to clean up the spill.

In a review paper published in the journal Nature Reviews Earth & Environment, WHOI marine geochemists Elizabeth Kujawinski and Christopher Reddy review what they— and their science colleagues from around the world—have learned from studying the spill over the past decade.

“So many lessons were learned during the Deepwater Horizon disaster that it seemed appropriate and timely to consider those lessons in the context of a review,” says Kujawinski. “We found that much good work had been done on oil weathering and oil degradation by microbes, with significant implications for future research and response activities.”

“At the end of the day, this oil spill was a huge experiment,” adds Reddy. “It shed great light on how nature responds to an uninvited guest. One of the big takeaways is that the oil doesn’t just float and hang around. A huge amount of oil that didn’t evaporate was pummeled by sunlight, changing its chemistry. That’s something that wasn’t seen before, so now we have insight into this process.”

Released for the first time in a deep ocean oil spill, chemical dispersants remain one of the most controversial debates in the aftermath of Deepwater Horizon. Studies offer conflicting conclusions about whether dispersants released in the deep sea reduced the amount of oil that reached the ocean surface, and the results are ambiguous about whether dispersants helped microbes break down the oil at all.

“I think the biggest unknowns still center on the impact of dispersants on oil distribution in seawater and their role in promoting—or inhibiting—microbial degradation of the spilled oil,” says Kujawinski, whose lab was the first to identify the chemical signature of the dispersants, making it possible to track in the marine environment.

Though the authors caution that the lessons learned from the Deepwater Horizon release may not be applicable to all spills, the review highlights advances in oil chemistry, microbiology, and technology that may be useful at other deep-sea drilling sites and shipping lanes in the Arctic. The authors call on the research community to work collaboratively to understand the complex environmental responses at play in cold climates, where the characteristics of oil are significantly different from the Gulf of Mexico.

“Now we have a better sense of what we need to know,” Kujawinski says. “Understanding what these environments look like in their natural state is really critical to understanding the impact of oil spill conditions.”

Additional authors of the review are chemist Ryan P. Rodgers (Florida State University), and microbiologists J. Cameron Thrash (University of Southern California, Los Angeles), David L. Valentine (University of California Santa Barbara), and Helen K. White (Haverford College).

 

Funding for this review was provided by the Gulf of Mexico Research Initiative, the Henry Dreyfus Teacher-Scholar Award, the National Academies of Science, Engineering, and Medicine Gulf Research Program, and the National Science Foundation.

Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit www.whoi.edu.

Key Takeaways

  • Some coastal ecosystems around the Gulf of Mexico recovered, but in areas such as deep-sea coral communities, the oil, gas and dispersants combined with other stressors to create long-lasting impacts.
  • Gene analysis tools, used on a wide scale for the first time, provided unprecedented insights into which microbes consumed oil, gas and dispersants in marine ecosystems.
  • Advanced chemical analysis showed for the first time that weathering on the ocean surface, particularly by sunlight and oxygen (photo-oxidation), changed the composition of oil but reduced the effectiveness of dispersants applied to the surface.
  • The spill science community can be most effective by working collaboratively across academia, industry and government in the event of future oil releases in the deep sea and high latitudes.

Oceanus Magazine

While Oil Gently Seeps from the Seafloor

While Oil Gently Seeps from the Seafloor

May 14, 2009

I investigate what happens to oil spilled into the ocean—with an eye toward finding better ways to “engineer” cleanups. But the brass ring has always hung out of my reach. When oil hits the water, chemical changes start occurring fast. It’s not like I can predict where or when an accidental spill is going to occur, so I usually can’t get to spills fast enough. I literally and figuratively miss the boat.

When the M/V Cosco Busan struck the San Francisco-Oakland Bay Bridge in November 2007 and spilled 58,000 gallons of heavy fuel oil, for example, I had to mobilize singlehandedly to get plane tickets, transport scientific gear, outline a plan to take samples, and arrange for a boat.

In the immediate aftermath of an oil spill, rapid response teams have their hands full with their primary mission of preventing more spillage and mitigating the damage. They aren’t in the business of sampling and studying oil. It took me a week to get on the scene, and during those precious seven days, nature already had moved the oil and changed its chemical composition. What happened to the oil in those seven days?

“Oil,” you see, is actually a motley stew made up of thousands of different compounds—each with distinctive chemical structures that give them distinct properties. When oil spills into the ocean, some compounds evaporate, while others break down in sunlight, or dissolve in seawater, or get eaten by microbes, or sink and stick to sediments. By the time I arrived, I had missed half the action. I could not explain what happened and why with much certainty.

An oil spill every day

But I got a break in January 2005. I was aboard a 20-foot motorboat a mile offshore from the campus of the University of California at Santa Barbara (UCSB) with my colleague, Dave Valentine, a UCSB marine geochemist. The water was calm and flat—dampened by a widespread, iridescent film of oil on the surface. Big oil patties floated about. The air smelled like diesel fuel.

By any definition, it was a classic oil spill. But we were the only boat in the area—no Coast Guard, no oil booms, no throngs of cleanup crews in white Tyvak suits, no helicopters, no media, and no shipwreck.

Why? Because this oil spill was entirely natural. The oil had seeped from reservoirs below the seafloor, leaked through cracks in the crust about 150 feet (45 meters) under water. Lighter than seawater, the escaped oil floated to the ocean surface.

It was one of those days in your career that you never forget. Adrenaline raced through my body, and my brain was in overload, thinking about the research that could be done at this site. Nature was offering an ongoing experiment that was impossible (not to mention illegal) for me to perform. Off Santa Barbara, there’s an oil spill every day, allowing us to take a close look at a process that previously eluded our grasp.

I vividly remember standing on the boat and calling my lab manager, Bob Nelson, telling him to book a plane ticket and pack a long list of gear. We returned days later to start investigating the fate of oil in the coastal ocean, using this readily accessible natural laboratory.

Following an oily trail

I had learned about natural oil seeps in graduate school, and I knew that they account for about 50 percent of oil that ends up in the coastal environment. That’s five times as much oil as is delivered by accidental spills.

The Santa Barbara seeps, for example emit 5,280 to 6,600 gallons (nearly 20 to 25 tons) of oil per day, and natural seeps have been active for hundreds to thousands of years. Local Native Americans used the oil to waterproof their boats. But I just didn’t appreciate how spectacular they were and what a powerful opportunity they provided to study oil spills.

In our initial research, Dave and his scuba-diving team collected bubbles of oil that trail out in a line from a seafloor seep (we call these “stringers”). We compared this oil with samples extracted from a nearby offshore drill rig, which tapped into the same reservoir that leaked oil out of the seafloor seeps.

We analyzed the specimens using a technique called “comprehensive two-dimensional gas chromatography (GC×GC).” The instrument reveals distinct chemical “biomarkers” in the oil, which like genetic markers allow us to track the oil’s source and lineage. It also lets us identify and differentiate the thousands of compounds that oil is composed of.

To our surprise, we discovered for the first time that on the oil’s journey up to the seafloor, approximately 1,000 compounds in the oil were devoured by microbes living in the rocks beneath the sea floor. Some ate the oil and created intermediate byproducts. These were subsequently eaten by other microbes that likely converted the oil into natural gas.

We also compared the compounds in oil seeping out of the seafloor with those in oil at the sea surface. We discovered that about 10 percent of the remaining compounds in the oil evaporated within seconds or minutes after it had floated to the surface. That was something we had never been quick enough on the scene to measure before in accidental spills.

With UCSB graduate student George Wardlaw as lead author and three other co-authors, we reported our findings in the October 2008 issue of Environmental Science & Technology.

Then it was on to the next steps—tracking how much oil at the surface sank back into the mud atop the seafloor.

The fallout from the seeps

In the summer of 2007, we brought in a boat quite a bit bigger than the little motorboat we used in 2005—Woods Hole Oceanographic Institution’s (WHOI) 274-foot-long research vessel Atlantis, the mother ship for the research submarine Alvin. The two usually work in the deep ocean, but this time Alvin dove to only a fraction of its 4,500-meter depth capacity, allegedly setting a record for its shallowest science dive ever.

We used Alvin to observe spectacular shows of oil and gas seeping and bubbling up from cracks at the ocean bottom. And one evening after Alvin surfaced for the night, I, Dave, and Chris Farwell, a UCSB undergraduate student at the time (and my cabin mate aboard Atlantis) began collecting samples of sediments starting 2.2 nautical miles (4 kilometers) downstream of the oil seeps.

We sampled 16 locations with various water depths over a 35-square-mile (90-square-kilometer) grid, with an additional comparison sample obtained from within the seep field itself. I tip my hat to Capt. A.D. Colburn, the Atlantis crew, and shipboard technician Dave Sims for making this sampling effort so seamless in shallow coastal waters in which they don’t typically work. We finished as the sun was rising and the Alvin group was preparing the submarine for another dive.

After the cruise, under Dave’s (and occasionally my) direction, Chris began a thorough study on these samples. He came to Woods Hole for a week, staying with me and my wife Bryce and working in my lab. (To earn his keep, I made him scrape wallpaper in our house.)

Chris found plenty of oil in the samples to keep him busy. Once again, biomarkers revealed by GC×GC showed that the oil in the sediments matched the oil floating on the sea surface, the oil leaking out of the seeps, and the oil extracted from the subseafloor reservoir. We could say with confidence that the oil we found in the sediments came from the oil reservoir and not from an accidental spill or runoff from land.

In collaboration with Libe Washburn, a physical oceanographer at UCSB, Dave and Chris estimated that oil on the surface stayed in the water from about 10 hours to five days before settling back into the sediments. Chris’s study revealed that the oil content was highest in sediments closest to the seeps and gradually diminished over distance as it was dispersed by currents—much the way smoke trails away in the wind.

At WHOI, Bob Nelson and Emily Peacock found that the composition of the oil in the sediments had changed significantly from what we had found floating in the ocean surface; only a few, very large chemical compounds remained in the sediments. Our findings were published in the May 2009 issue of Environmental Science & Technology.

Munching microbes

Nature had done an amazing job on the oil, but nature appears to have a limit on its capacity to break down oil. Why this happens is one of my keen research interests. We think the compounds in the sediments have remained because their bulky structures make them hard to evaporate, insoluble in water, and more difficult for microbes to digest.

Microbes are astonishing and voracious little critters. They can eat almost anything, but our research at the Santa Barbara oil seeps shows they do it systematically: They select compounds whose size and shape are the easiest for them to degrade. So they will chow down on a simple, straight-chained alkane, but will avoid a hopane with twice as many carbon and hydrogen atoms bonded in rings that offer difficult access for enzymes. If they were at a buffet, they would devour the pudding, soup, and rice first and eschew the chewy corned beef and stale crusty bread.

Another result of our study is that for the first time, we can quantify the amount of oil residue that ends up in seafloor sediments after a “natural” oil spill. To compare the amount the oil in the Santa Barbara sediments with a figure people might understand, it’s equivalent to 8 to 80 times the oil spilled in the Exxon Valdez accident. But our study by no means is a direct comparison on the overall fate and impacts of the Exxon Valdez spill and the Santa Barbara seeps.

That estimate is as close as we could get, since we don’t know how thick the layer of sediments is. But before this research, for all we knew, it could have been the equivalent of 0.0001 or 10,000 Exxon Valdez spills.

Many people in the Santa Barbara region still believe that oil found in the ocean and on nearby beaches comes from oil rigs, but our research points the finger at the natural oil seep. At the same time, this natural oil seep is teaching us many extraordinary lessons about how oil responds in our ecosystem. And that offers better strategies for people to respond to the oil they spill accidentally into our ecosystems.

This research was funded by the National Science Foundation, the U.S. Minerals Management Service, the California Toxic Substance Research and Training Program, the Department of Energy, the WHOI Coastal Ocean Institute, and the Seaver Institute.

Tracking Nitrogen's Elusive Trail in the Ocean

Tracking Nitrogen’s Elusive Trail in the Ocean

December 12, 2008

Humans often seem to be unable to fix a problem without creating a new one. We invented DDT to kill mosquitoes and stop the spread of malaria, but almost caused the extinction of bald eagles and other birds. For industry and transportation, we developed fossil fuels, whose greenhouse gas emissions are now causing global climate change. And we invented a way to extract nitrogen from the air to make fertilizers that bolstered agriculture and helped feed hungry populations. But ultimately that has upset the balance of nitrogen, especially in the oceans, causing a rash of new dilemmas that we now confront.

Fertilizers have leaked into the oceans through wastewater and runoff from farms and lawns, loading coastal waters with excess nitrogen that fertilizes the rampant growth of marine plants. The decomposition of these multitudes of phytoplankton removes oxygen from seawater, creating oxygen-poor “dead zones” where fish cannot live. The situation also may be leading to the increased production of nitrous oxide, a gas that traps heat 300 times more efficiently than carbon dioxide and also destroys ozone. (See Another Greenhouse Gas to Watch: Nitrous Oxide.)

Any attempt to restore the nitrogen balance on our planet requires far more understanding than we now have of how nitrogen moves through the environment. To find solutions to these problems, we first need to determine how much nitrogen is entering the ocean, what happens to it once it gets there, and how much eventually gets removed or recycled back to the atmosphere. But tracking nitrogen—as it gets incorporated into various chemical compounds in the air, in the ocean, and in organisms—has been a daunting challenge.

Nitrogen’s journey through the oceans is largely mediated by microbes. To live and grow, a variety of microbes use nitrogen in different ways, metabolically transforming it into diverse chemical compounds. They cycle it quickly and often concurrently in the same places in the vast ocean, so that we humans can’t easily measure the chemical processes that are taking place.

But we’re trying. As a graduate student in the MIT/WHOI Joint Program, I am working on a new method using a natural tag to follow nitrogen’s trail. The tag that I measure can record nitrogen’s chemical life history: where it came from, what chemical reactions it has undergone, and how and where it ends up.

Fixing nitrogen and food shortages

Nitrogen gas (N2) makes up 78 percent of our atmosphere, but most organisms cannot utilize this source of nitrogen to grow, because the nitrogen atoms are held together by a tight triple bond so strong that it requires extreme temperatures and pressures to break.

In the early 20th century, German scientist Fritz Haber won the Nobel Prize for inventing a method to rip this bond apart and create other nitrogen-containing compounds that are more available for industrial use. He needed to use temperatures of 932° to 1,832°F (500° to 1,000°C) and pressures 100 to 250 times atmospheric pressure to break the triple bond.

The Haber process starts with so-called “non-fixed” forms of nitrogen, which aren’t easily usable—nitrogen gas (N2), for example, or other nitrogen-containing gases such as nitrous oxide (N2O) and nitric oxide (NO). The process converts them into easily usable “fixed” forms of nitrogen, such as ammonia (NH3), nitrate (NO3), or nitrite (NO2), which are essential nutrients for organisms to grow.

The Haber process provided a new supply of “fixed” nitrogen to make fertilizers that are now responsible for sustaining one-third of the world’s population. In the future, however, with rising population and demands for food and energy, human-made sources of nitrogen in the environment are projected to double the natural input to the environment, reported two of the world’s leading nitrogen cycle experts, Nicolas Gruber of the Swiss Federal Institute of Technology and James N. Galloway of the University of Virginia, in the journal Nature in 2008.

Which brings us to our current predicament.

Agricultural runoff can overload coastal waters with nitrogen. Every year, for example, a mother lode of nitrogen drains into the Mississippi River, mostly from agricultural lands, and pours into the Gulf of Mexico. It stimulates a phytoplankton bloom and then an oxygen-depleted dead zone covering an area almost the size of New Jersey.

Nutrient-rich, oxygen-poor waters like these support a frenzy of nitrogen cycling, in which certain bacteria use nitrates as an energy source. As they eat the nitrates, they form nitrites as an intermediate chemical byproduct. What happens to the nitrites is key. They can either be converted back to nitrates and reused as food by other microbes. Or they can be converted to nitrogen gas and released back to the atmosphere. How can we follow what happens to the nitrites?

Isotopes to the rescue

With the help of my Ph.D. advisor, Karen Casciotti, I’m developing a way to use isotope ratios to track different chemical transformation processes involving nitrogen. Isotopes are atoms of the same element that have different weights. In my case, I study 14N and the heavier 15N, as well as two isotopes of oxygen: 16O and 18O. The key is that in chemical reactions, atoms with different weights behave a little differently.

Imagine your mom asks you to move 20 bricks from a pile of 100 bricks in the driveway to the basement. Some weigh 14 pounds, let’s say, and the others weigh 15 pounds. Which bricks will you choose to move? The light ones, of course! After you are done moving your 20 bricks, the pile in the basement will have a larger ratio of light to heavy bricks than the pile in the driveway.

Similarly, microbes moving nitrogen around with their biochemical reactions usually pick lighter or heavier isotopes of nitrogen. So different microbes using different chemical reactions will produce end products with different ratios of heavy and light isotopes. We call this phenomenon an “isotope effect,” and if we can measure these isotope effects, we can distinguish the reactions that produce them.

Sorting out the nitrogen cycle

In the Watson Laboratory at Woods Hole Oceanographic Institution, I’m conducting experiments with marine nitrite-oxidizing microbes first discovered in the 1970s by Stanley Watson (after whom the building is named) and John Waterbury, a scientist emeritus on the floor below me. Waterbury became an expert at culturing marine microbes like these and maintains a “library” of microbes in the Watson Lab that other scientists can use in their experiments. Nitrite-oxidizing microbes convert nitrite back into nitrate, and they are the only natural source of nitrate to the oceans.

In my experiments, I measured the isotope ratios of nitrogen and oxygen atoms in nitrate produced by these microbes from nitrite. We’ve discovered something unique about these bacteria—they actually prefer to move the heavy isotopes, 15N. That’s unexpected and interesting, but more important, it reveals something new about the oceanic nitrogen cycle. This information helps us track chemical pathways and determine how much nitrite is recycled naturally back into nitrate, which is reused by other microbes in the ocean, and how much is converted into nitrogen or nitrous oxide gas, which is released back into the atmosphere.

Our experiments offer the promise that we can perform similar isotopic analyses of other chemical reactions that are going on in the ocean and begin to reveal exactly what is happening to the extra nutrients we are adding to our oceans. Can we continue to “fix” nitrogen into fertilizers without disrupting the natural environment? We won’t know until we better understand exactly how human activities are affecting the nitrogen cycle. And that’s where I can help.

Carly Buchwald was supported by the J. Seward Johnson Fund and an MIT Presidential Fellowship. The research is funded by the National Science Foundation. This article was written during a science writing course for graduate students at WHOI, supported by funds from The Henry L. and Grace Doherty Professor of Oceanography.

Listening In As Bacteria 'Talk' to Each Other

Listening In As Bacteria ‘Talk’ to Each Other

November 3, 2008

The 27th of January, at the entrance of the vast Bay of Bengal … about seven o’clock in the evening, the Nautilus … was sailing in a sea of milk. … Was it the effect of the lunar rays? No: for the moon … was still lying hidden under the horizon. … The whole sky, though lit by the sidereal rays, seemed black by contrast with the whiteness of the waters. “It is called a milk sea,” I explained.
—20,000 Leagues Under the Sea, Jules Verne, 1870

Throughout the vast oceans, silent conversations are regularly taking place among the Earth’s most primordial life forms. The multitudes of single-celled bacteria that inhabit the oceans have evolved a way to communicate with each other, come together, and coordinate their behavior. Bacteria talk, and in our lab at Woods Hole Oceanographic Institution, we are trying to eavesdrop on their chatter.

The process bacteria use has been dubbed “quorum sensing.” You can think about it this way: In Congress or a corporate boardroom, you need to muster a minimum number of individuals—a quorum—to conduct business or accomplish something together; the same is true in the microscopic realms of the ocean.

One example is collective defense: A bacterium, alone and floating in the ocean, is an easy target for a marauding protist. But itinerant bacteria have evolved ways to aggregate into tightly packed, highly organized, and usually slimy communities called “biofilms,” which attach to hard surfaces. Like walled cities, these biofilms protect the individuals living within them from assaults.

The good, the bad, and the slimy

Biofilms are everywhere, and they have wide-reaching impacts. If you have ever felt the plaque on your teeth, slipped on a slimy rock at the beach, or been frustrated by ugly green slime on the hull of your boat, you have had a close encounter with a biofilm.

In the human body, bacteria that cause dental cavities, ear infections, and fatal lung diseases in cystic fibrosis patients, for example, all forge biofilms. These act as a fortress to protect the bacteria from the body’s immune response or antibiotic treatments while they build their ranks and prepare to attack their host.

Similarly, biofilms serve as a refuge for disease-causing bacteria in the ocean. Biofilms transported on ships, the shells of marine animals such as lobsters, or on microscopic copepods can help spread and transmit pathogens such as cholera.

Biofilms are detrimental in other ways. They foul and clog water pipes. They form the substrate on which nuisance organisms such as barnacles settle on ship hulls. The U.S. Navy spends more than $100 million every year on fuel to overcome biofilm-induced drag on their vessels. In fact, much of the information we have about the structure and function of biofilms has been discovered by scientists interested in controlling and eradicating them. These include ways to prevent biofilm-forming infectious bacteria from building their biofilm fortress in the first place, leaving them susceptible to more traditional antibiotic approaches.

But biofilms also play essential, positive roles in a variety of critical natural processes and provide innumerable crucial ecoogical services. They provide habitat for beneficial bacteria, algae, and higher organisms. Swarms of bacteria detoxify pollutants in lakes, rivers, and oceans. By decomposing and recycling organic material, they help keep nutrients circulating in the food chain like money in financial markets.

Via behaviors regulated by quorum sensing, bacteria play a significant role in determining what happens to carbon in the ocean: whether it sinks to the depths and is buried as detritus on the seafloor, or converted into the greenhouse gas carbon dioxide and released back to the atmosphere.

How bacteria talk the talk

Bacteria communicate via “chemical” conversations. The “words” they use are small molecules. One variety of chemical “words” particularly common in the marine environment are modified amino acids called acylated homoserine lactones or AHLs, for short.

The basic process of quorum sensing is pretty simple. Bacteria are constantly producing a few AHLs, which diffuse through bacterial cell membranes into the environment. If no other AHL-producing bacteria are out there, the AHLs will diffuse away and quickly degrade, and bacterial “silence” will prevail.

But if enough AHL-producing bacteria are in the vicinity, the concentration of AHLs outside the bacteria will eventually rise. That’s the chemical signal to each bacterium that they’ve got a lot of buddies in the area. In this way, the bacteria sense that they have sufficient density, that they have achieved a quorum.

The communal buildup of AHLs triggers the production of more AHLs by individual bacteria, which keeps the process going—something called an autoinduction response. The AHLs bind to protein receptors, which interact with bacterial DNA and help to turn on genes inside all the bacteria throughout the quorum. The genes activate behaviors that would not have been worthwhile for an individual bacterium but are now collectively advantageous: They produce enzymes, secrete toxins, or produce the biochemical building blocks that will fortify the biofilm.

Ready, set, glow

In some bacteria, quorum sensing triggers the production of enzymes that catalyze light-producing reactions. The bacteria appear to glow! Swarms of bioluminescent bacteria are the presumed source of the “milky seas” that many sailors have periodically observed over the centuries and that Jules Verne described in 20,000 Leagues Under the Sea.

In fact, the phenomenon of bioluminescence sparked the discovery of quorum sensing 40 years ago,  when researchers were studying how Hawaiian bobtail squids glow. They found that a bacterium, Vibrio fischeri, aggregates in the squids’ light organs in a symbiotic relationship. In exchange for a protected, nutrient-rich environment to live in, the bacteria do something as a community that they wouldn’t do as individuals: They glow.

The benefit that the bacteria get from bioluminescencing is still under debate, but we do know what’s in it for the squid. It counter-illuminates and camouflages their shadows when they are active on moonlit nights, so they aren’t as easily detectable by predators.

Quorum sensing research at WHOI

As it turns out, quorum sensing is a ubiquitous process in the types of bacteria that dominate marine microbial communities. With my research advisor, Ben Van Mooy, I have been using novel analytical approaches to try and home in on the fleeting chemical “words” used by marine bacteria.

I sample biofilms from all manner of marine environments in hopes of catching these conversations in action. I scrape slime from rocks I find on Vineyard Sound beaches, from ship hulls in local waters, and from sediments in the Chesapeake Bay. I isolate bacteria from seawater in the Indian Ocean and from the backs of marine organisms.

I bring these natural samples back to the lab, where we extract any AHLs present in the samples into organic solvents, just as you might make a cup of tea by extracting tea leaves with hot water. We then subject the extract to liquid chromatography, a process that can tease apart all the different molecules in the extract.

We then use a mass spectrometer to bombard the molecules with high energy, which smashes them into smaller pieces (think about what happens if you drop a ceramic dish onto the floor). By examining the size of each of these pieces, we can put them back together like a puzzle and identify the exact chemicals that were in the original extract.

Quorum-sensing bacteria are very sensitive to AHLs and so the molecules are usually present in very low concentrations. In the lab, scientists can cultivate very large batches of bacteria and isolate very large quantities of AHLs. However, in the environment, bacterial populations are so much smaller and dispersed over much wider areas. Both of these factors make it much more challenging for us to obtain detectable quantities of natural AHL.

But this isn’t the only obstacle that has limited scientists’ ability to eavesdrop on natural bacterial communities. AHLs are very sensitive to the acidity or alkalinity of seawater, and they degrade quickly in the ocean. In our lab, we have been measuring how quickly; it turns out that, on average, each AHL molecule self-destructs in just a few hours. So we have to make our measurements soon after we collect our samples from the ocean.

‘It is called a milk sea’

Our pot of gold would be a large-scale bacterial quorum in the ocean. Indeed, a recent and tantalizing observation suggests that large-scale, conspicuous bacterial quorums do exist.  In 2005, scientists at the Naval Research Laboratory, Monterey Bay Research Institute, and the National Geophysical Data Center reported a “milky sea” that had occurred a decade earlier. It covered an area of 5,946 square miles in the Indian Ocean.

The Indian Ocean bioluminescence had all the characteristics that it was produced by bacteria. A huge bloom of phytoplankton had blanketed the ocean surface. Hordes of bacteria in the area massed onto the phytoplankton like swimmers on a fleet of rafts. When they sensed they had achieved a quorum, they signaled each other to glow, collectively bright enough to be seen by satellite.

To produce that much light, more than a billion trillion (1022, or 1 with 22 zeroes after it) cells would have had to be present in that 5,946 square miles. That’s quite a large quorum.

Now it is just a matter of time before we catch the ocean’s most conspicuous bacterial quorum in action. We hold out hope that we may be at the right place at the right time during research cruises we have planned over the next two years.

Meanwhile, our lab continues to make progress in deciphering the chemical conversations of bacteria within less spectacular, though no less significant, biofilms on marine particles and phytoplankton. Ultimately, our work may reveal how decisions made in tiny bacterial boardrooms have impacts that are felt throughout the vast oceans and atmosphere.

Laura Hmelo has been supported by a National Science Foundation graduate fellowship and the J. Seward Johnson Fund. The research was funded by the Office of Naval Research. This article was written during a science writing course for graduate students at WHOI, supported by funds from The Henry L. and Grace Doherty Professor of Oceanography.

Researchers Band Together to Create a Band

Researchers Band Together to Create a Band

October 27, 2008
How Does Nature Deal with Persistent Pollutants?

How Does Nature Deal with Persistent Pollutants?

October 22, 2008

Why would I choose to spend my years in graduate school up to my elbows in foul-smelling whale blubber? To explore how some of the most notorious man-made pollutants reach dangerous concentrations in large predators, even when concentrations of these pollutants in seawater are low and considered “safe.”

When I entered graduate school I knew that some man-made pollutants could be concentrated in large predators. I had heard how DDT caused the collapse of bald eagle populations, and I was aware that eating a lot of swordfish was a bad idea because of mercury contamination. But I was surprised and intrigued when my Ph.D advisor, Christopher Reddy, explained that researchers have recently discovered a few naturally produced chemicals that also accumulate with each link up the food chain—a process called biomagnification.

These natural biomagnifying compounds have existed in the environment for eons, far longer than their man-made counterparts, with no apparent harm to the environment.  Ecosystems have evolved with these compounds and seem to be able to deal with their presence. So, if we can better understand how naturally produced biomagnifying compounds travel through—and eventually exit—ecosystems, we can better predict the pathways and fates of man-made biomagnifying pollutants now littering the oceans.

When I explained my research to my father, he had his own take on it: “Very interesting theory,” he said, “Learning from Mother Nature to help clean up the kids’ messes.”

The ins and outs of ecosystems

Biomagnification occurs when contaminants that don’t easily degrade increase with each link of a food chain. And they don’t go away—they can stick around for decades, and maybe even centuries. That is why most of the world has banned or restricted their use.

Here is what happens. In seawater these persistent molecules stick to small particles and phytoplankton. Small fish eat the phytoplankton, but the contaminants can’t be broken down and are absorbed, intact, by the fish. When small fish are eaten by larger predators, the process repeats—again and again, up the food chain. Each subsequent predator receives a higher dose than the previous one. Animals at the top of the food chain, such as dolphins, receive the most concentrated dose of these contaminants with every meal.

Biomagnification has been well known among some man-made pollutants but not for natural products. Until Chris introduced me to biomagnifying natural compounds, natural compounds had all sorts of good connotations in my mind: therapeutic, gentle, miracle drugs. But I should not have been surprised to have this worldview overturned. After all, brevetoxin, the naturally produced red tide poison, graces the cover of my college organic chemistry textbook.

But even after grappling with the concept of potentially harmful natural products, I was still captivated by the idea that some natural products could biomagnify. Why? Basically, because nature usually balances its checkbook. Whatever enters an ecosystem eventually gets processed back out. Over time, the incoming and outgoing amounts should be equal.

The Cape Cod Stranding Network

Studying these long-lived natural products requires analyzing marine animals. To make my job easier, I start with samples rich in biomagnified contaminants—blubber!

But how do you get your hands on pounds and pounds of blubber? Whales, dolphins and seals are protected; we can’t hunt them or take their lives in the name of science. As a child, I was enthralled by these magnificent animals, and I still am. I wouldn’t want to harm them for any purpose, scientific or otherwise.

Fortunately, my lab works with the Cape Cod Stranding Network (CCSN), which strives to help the hundreds of animals stranded each year on the beaches of Cape Cod. Rescuers push some back out to sea, and bring others into aquariums for rehabilitation and release.  But, unfortunately, some animals just don’t make it.

The CCSN ensures that these losses benefit living animals by performing necropsies (the animal equivalent of autopsies) and distributing tissues to researchers for studies on diseases, boat/motor-collisions, and, for me, chemical analyses.

Make mine a whale smoothie

From the large slabs of frozen blubber that I receive from the CCSN, I make a viscous, brilliantly yellow, and very fragrant oil. Unlike the whalers of previous generations, I do not “cook” the oil out of the blubber, because that might alter its chemical signature.  Instead, I use a blender to make a blubber “smoothie.”

It is really quite gross. However, simply by filtering this pungent “smoothie,” I end up with clear, banana-yellow oil that those long-ago whalers would envy.

All the compounds that I analyze are floating around in this oil. To separate them from the oil, I take advantage of the size difference between the oil molecules, which are very large, and my compounds, which are very small.

I pass the oil through a long glass column packed with particles that have tiny cavities.  The small molecules go in and out of these cavities. They take their time and pass through every nook and cranny. The larger oil molecules can’t fit in the crevices, so the bright yellow oil rushes straight through. I discard the oil and collect the interesting molecules all by themselves.

I still need to purify my extract further. I repeat the process using different columns that separate molecules by different properties, such as volatility (how easily they escape into the air) or polarity (how electrons are arranged in a molecule). As molecules emerge from the final column, I can determine their identities and how much was present in the original blubber.

Natural cousins of pollutants

In my four years as a graduate student, I’ve established that a new class of natural compounds is widespread in the blubber and livers of marine mammals in the North Atlantic. The impossible-to-pronounce name for these chemicals is the halogenated 1’methyl-1,2’-bipyrroles, commonly abbreviated MBPs.

We don’t yet know where MBPs come from, what function they might provide, or why they accumulate in marine mammals. But we can tell that MBPs are remarkably similar to many man-made pollutants that biomagnify. Both turn up in similar amounts in my blubber and liver samples. This suggests that MBPs biomagnify as well.

To confirm that MBPs biomagnify, my next step is to analyze lots of fish, squid, crustaceans and plankton from the Northwestern Atlantic—creatures representing other links within this food chain. By measuring MBP concentrations in these samples, I’ll see if MBPs really do magnify at each level.

Now, I just have to get my hands on lots of fish. As far as I know, there is no “Fish Stranding Network.” But the National Marine Fisheries is just down the road from my lab, and I hear they take requests.

Kristin Pangallo’s research was funded by the National Science Foundation, The Seaver Institute, the J. Seward Johnson Fund, and The Virginia Walker Smith Fund. This article was written during a science writing course for graduate students at WHOI, supported by funds from The Henry L. and Grace Doherty Professor of Oceanography.

The Spiral Secret to Mammal Hearing

The Spiral Secret to Mammal Hearing

September 17, 2008
For Graduate Student, Research Is a Gas

For Graduate Student, Research Is a Gas

July 24, 2008

When you spend 40 days on a ship in the South Atlantic, enduring equipment failures, icebergs, and the occasional surly shipmate, you should at least get to see a few penguins for your trouble.

But when Naomi Levine went to sea in the winter of 2005—her second cruise as a graduate student in the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution (MIT/WHOI) Joint Program—she missed her chance.

As researchers aboard the Ronald H. Brown collected samples early each morning in the chill air, penguins would gather alongside the ship in the dawn rays, said Scott Doney, a WHOI marine chemist and Levine’s Ph.D. co-advisor.

It would have been a thrilling sight—if Levine ever got to see it. But she had to work each morning in the computer room, only coming on deck once the penguins had scattered.

“She thought we were pulling her leg about the penguins,” Doney recalled. “She never actually got to see them in the open ocean on that cruise.”

Levine, though, took the whole experience—seven-week cruise, cold weather, 12- to 14-hour workdays, no penguin sightings—with her usual good humor. “She almost always has a smile on her face,” Doney said.

“Conducting research at sea is mentally, physically, and emotionally taxing,” she said. “I would have loved to see the penguins, but that was the least of my worries.”

Legislation versus the lab

Growing up outside Boston, Levine said she was drawn to earth science by a great teacher in high school. “He showed us how you could use clues from the Earth to figure out what happened millions of years ago.”

So at Princeton University, Levine took geology courses and studied deep-Earth geochemistry. But she was also interested in environmental policy and climate, which led her to the oceans.

“I wanted to work on something more immediately relevant to society,” Levine said. “There’s so much we don’t know about the oceans and their effect on climate that it seemed like a perfect fit.”

After graduation, Levine got a job at the nonprofit organization Environmental Defense, exploring her interest in environmental policy. She worked on reports showing how climate change could affect different parts of the country. Those reports were used to encourage clean car legislation and to build congressional support for reducing carbon dioxide emissions.

She enjoyed the work, but “I wasn’t doing scientific research,” she said. “I was only reading other people’s research, and I missed being in the lab.”

The experience convinced her, however, that she wanted to focus on climate, which led her to WHOI and Doney’s lab in 2004.

Researchers have been sampling the oceans since the 1980s, on cruises like the one Levine was on in 2005, to measure the buildup of human-produced carbon in the oceans. Using computer models, Levine is evaluating the accuracy of those calculations and identifying regions of the oceans where current methods may not be very accurate.

“Ultimately, our goal is to get a better picture of how much manmade carbon dioxide is ending up in the ocean, which lets us better predict changes in Earth’s climate,” she said. (See How Long Can the Ocean Slow Global Warming?)

From CO2 to DMS

With her other Ph.D. co-advisor, WHOI marine chemist Dierdre Toole, Levine is now studying dimethylsulfide, or DMS, a naturally produced gas that influences Earth’s climate. It encourages the formation of clouds that reflect solar radiation back into space and, as a result, cool the Earth’s surface. DMS is made from a larger chemical compound called dimethylsulfoniopropionate, or DMSP, which is made by tiny marine plants, or phytoplankton. Levine’s research focuses on how DMSP is broken down by bacteria and other phytoplankton to form the DMS that eventually gets into the atmosphere. (See DMS: The Climate Gas You’ve Never Heard Of.)

In 2007, Levine went on seven 5-to-10-day research cruises from Bermuda to the Sargasso Sea, where she measured DMS concentrations and the rates of DMS formation. She will do 10 more cruises in 2008. She developed a method to measure the activity of bacterial enzymes that break down DMSP into DMS. That gives scientists the ability for the first time to figure out who’s responsible for the critical DMSP-to-DMS conversion—phytoplankton or bacteria.

“In large regions of the ocean, like the Sargasso where I am doing my field research, we believe that bacteria are the primary DMS producers,” Levine said. “However, there are other regions of the ocean, like the Southern Ocean around Antarctica, where phytoplankton appear to be the primary DMS producers.”

It gets more complex. The bacteria that she’s studying don’t break DMSP apart the same way every time. Scientists call it the “bacterial switch,” which sends DMSP down one of two biochemical pathways. Sometimes bacteria split DMSP to produce DMS and a carbon compound—“a good carbon food source for them, which they need to grow,” Levine said. But at other times, the bacteria break down DMSP to get at the sulfur to make amino acids and proteins, a process that doesn’t generate DMS. Some bacteria do one or the other, and some do both.

“The bacteria have to make two different enzymes to go either for the sulfur or for the carbon,” Levine said. By tracking these enzymes—and the bacterial RNA and DNA that make the enzymes—Levine can track the “bacterial switch” and investigate what factors influence the bacteria to make DMS versus processing the sulfur.

“It might be as simple as when there’s a lot of other sources of carbon around, they go after the sulfur in DMSP instead,” she said.

“Understanding when and why bacteria make DMS will allow us to better predict DMS production, and better estimate how DMS will affect the global climate in the future,” Levine said. “Global warming most likely will have significant impacts on the surface ocean and the phytoplankton and bacteria that live there. If, under new climate conditions, more DMS is produced, it will act to cool the Earth, thereby counteracting global warming. We do not know exactly how much this effect might be, but some estimates are that it could be significant. However, a decrease in DMS production will act to augment global warming.”

Levine is Toole’s first graduate student, and she says that working with Levine may be spoiling her. “I could not imagine a better student,” Toole said. “You tell her to try A, B, C and D, and she’ll come back at eight the next morning and say, ‘Done.’ ”

Sometimes that means missing the penguins.

Levine’s research is supported by the National Science Foundation; a National Defense Science and Engineering Graduate Fellowship; the MIT Scurlock Fund; and the J. Seward Johnson Fund, the Seth Sprague Educational and Charitable Foundation Fund, and the Ocean Ventures Fund—all at WHOI.

 
DMS: The Climate Gas You've Never Heard Of

DMS: The Climate Gas You’ve Never Heard Of

July 17, 2008

For generations of mariners, a tangy, almost sweet odor served as a signal that land was nearby. What sailors called “the smell of the shore” had the opposite meaning to landlubbers, who would catch the same sweet scent wafting over the waves and think of it as “the smell of the sea.” Seabirds probably don’t have a name for it, but the odor means something to them, as well: the opening of an all-you-can-eat buffet.

Part of what they’re all smelling is a little-studied gas known as dimethylsulfide, or DMS. Some seabirds, possessing a keen olfactory sense, use the scent to track down its source: blooms of algae floating near the ocean’s surface, where the microscopic animals, krill, and other crustaceans that gather to graze on algae provide the birds with a hearty meal. (See Seabirds Use Their Sense of Smell to Find Food.)

DMS does far more than ring the birds’ dinner bell, though. Scientists believe it represents a large source of sulfur going into the Earth’s atmosphere. As such, it helps drive the formation of clouds, which block solar radiation from reaching the Earth’s surface and reflect it back into space.

If DMS production is speeded up by global climate change, as many scientists believe it will be, then it could provide a cooling effect. That means DMS could help offset greenhouse warming.

That hopeful claim has been made for more than two decades. In 1987, British chemist James Lovelock and several colleagues popularized an idea first proposed by others that algae might play a vital role in regulating the Earth’s climate.

Lovelock is famed as the originator of the Gaia hypothesis, which suggests that the Earth functions as a single living organism and maintains the conditions necessary for its own survival. By encouraging cloud formation, Lovelock theorized, DMS might help keep the Earth’s thermostat at a fairly constant temperature.

But scientists still understand very little about how and why marine algae make DMS, how it moves through the food web in the upper ocean, or how much of it gets into the lower atmosphere. Despite its potential impact on climate, the amount of attention focused on DMS remains relatively small, and scientists continue to be uncertain whether it can make a major difference in global climate change.

John Dacey, a biologist at Woods Hole Oceanographic Institution (WHOI), is one of the few marine scientists who have devoted a great deal of time to studying oceanic DMS over the past few decades. He says he’s amazed and dismayed that carbon dioxide receives so much research funding right now at the expense of other basic science, when other gases may have critical roles to play in countering or augmenting warming.

“Environmentally, understanding DMS is incredibly important,” said Dierdre Toole, a marine chemist at WHOI. “DMS just isn’t fashionable, but I think it could have a hugely important role to play—more important than a lot of things that are fashionable right now.”

Critical but difficult measurements

Dacey has long investigated the processes that control how environmentally important gases are exchanged between Earth, ocean, organisms, and the atmosphere. He explored the little-understood role that plants play in influencing greenhouse gases. Dacey was the first to show how vegetation transferred methane to the atmosphere, and he demonstrated that DMS is emitted from the leaves of certain species of marsh grass. Scientists had previously thought the gas was coming from the sediment around the grass.

For the ocean, Dacey has also developed ways to track the exchange of DMS from sea to air. He is also studying how a molecule called dimethylsulfoniopropionate, or DMSP—the source of DMS—concentrates in organisms in the marine food web.

These are critical but difficult measurements to make. Dacey’s work over the decades on the dynamics of dissolved gases has required him to develop better measuring tools, including automated devices that allow researchers to sample repeatedly in order to detect changes.

In Dacey’s ongoing efforts to find better ways to measure DMS, he had collected three years’ worth of measurements on DMS concentrations in the Sargasso Sea off Bermuda. But this unique set of open-ocean data remained unanalyzed until scientists such as Toole recognized its potential.

DMS attracted Toole precisely because so little was known about it. With degrees in chemistry, geography, and marine science, Toole wanted a specialty that spanned her many interests. DMS offered all of that, and the sweet smell of mystery, too.

In frigid waters, a great bloom

When spring comes to the Ross Sea, just off Antarctica’s largest ice shelf, the ice begins to melt, and sunlight reaches nutrient-rich waters that have welled up from the ocean’s depths to the surface. The result: One of the largest, most predictable algal blooms in the world.

“You get a huge explosion of phytoplankton,” Toole said. Phytoplankton are tiny, single-celled floating plants that live near the ocean’s surface where enough light reaches to support photosynthesis. They’re the base of the ocean’s food web.

Toole and several colleagues have sought out the Ross Sea algal bloom for the past three years aboard an icebreaking ship. For a couple of weeks, the scientists have the phytoplankton all to themselves. “It’s almost like working in the lab,” Toole said.

Every morning, Toole took samples from the ocean, snapping the tops on bottles at different depths to collect the algae. In their cells, the phytoplankton synthesize DMSP. Physiologists aren’t sure why the algae need DMSP, but they speculate that it could have something to do with regulating salinity or temperature inside algal cells. In cold environments, DMSP may act as a cryoprotectant, keeping the cell from freezing. Some researchers have guessed that DMSP acts as a chemical repellant that helps deter predators.

Toole is more convinced that light—particularly ultraviolet light—explains why the algae produce DMSP. Working with David Siegel, a professor of geography at the University of California, Santa Barbara, Toole found that phytoplankton appear to convert DMSP into DMS when they’re stressed by ultraviolet radiation from the sun. The DMS flushes out chemically reactive molecules that cause cellular damage, in much the same way that our bodies use antioxidants to bind to free radicals.

“Phytoplankton respond dramatically to UV radiation stresses,” Siegel said. “This response is incredibly rapid.” Siegel and Toole documented their research in May 2004 in the journal Geophysical Research Letters.

As long as the algae are left alone, the DMSP stays relatively intact inside their cells, although some DMS leaks out and begins to make that DMS smell. Soon enough, though, once the algae in the Ross Sea have reached full bloom, zooplankton arrive and begin chowing down on them. DMSP spills out of munched-on algae into the ocean.

This in turn provides a feast for bacteria, some of which split the DMSP into components such as DMS, said Naomi Levine. A graduate student in the MIT/WHOI Joint Program, Levine is studying how bacteria send DMSP down a divergent biochemical pathway, something called the “bacterial switch.”

DMS dissolved in seawater begins to waft into the air and register on seabirds’ and researchers’ nostrils. “The entire place reeks of DMS,” Toole said. The odor may be pleasant enough in small quantities (“it has actually been described as a ‘positive flavor component’ in Pacific oysters,” Dacey said), but large doses of it make Toole gag. “I think I’ve brushed my teeth enough in DMS water that it just turns my stomach.”

A global thermostat?

Once DMS has moved from the ocean to the air, it starts to play an entirely different role: cloud maker.

DMS is chemically reactive and can’t last long in the atmosphere. It quickly gets converted into a variety of sulfur compounds that serve as aerosols. They allow water vapor to condense around them. This is how clouds are made.

Clouds, of course, have a major impact on the Earth’s climate. They deflect solar radiation back into space, preventing sunlight from heating the Earth’s surface and providing a cooling effect. Clouds are even more important over oceans, which are both more extensive and darker than land and so absorb a majority of the heat hitting the planet, Toole said. So the question becomes, can algae produce enough DMS to increase cloud cover and keep the planet’s temperature from rising?

“DMS is undoubtedly part of the system of checks and balances that keeps the climate from taking wild swings,” said Ron Kiene, a professor of marine sciences at the University of South Alabama and one of the world’s leading DMS researchers. Putting sulfur in the atmosphere, as with DMS emissions, is a more efficient way of cooling the atmosphere than removing carbon dioxide. So it might be possible for the natural feedback mechanisms of the biosphere to use DMS to limit global warming, he said.

Recently, Dacey spent a week in Barrow, Alaska, calibrating an automatic system for measuring very low volumes of DMS in the air. He hopes the measurements made at Barrow will reveal whether a scenario that starts with melting sea ice and leads to more open water, more phytoplankton, more DMS in the atmosphere—and hence greater cloud cover—will offset an increase in solar radiation absorbed by dark open water, rather than reflected by white ice.

DMS also comes into play in less natural, more intrusive proposals to remedy greenhouse warming. Proponents of ocean iron fertilization—seeding the oceans with iron to increase the growth of marine plants that absorb the greenhouse gas carbon dioxide—could have a potentially beneficial side effect. (See Fertilizing the Ocean with Iron). More phytoplankton could produce more DMS and more clouds.

In the July 2007 issue of the journal Atmospheric Environment, scientists from Los Alamos National Laboratory, the University of California Irvine, and New Mexico Tech suggested that fertilizing two percent of the Southern Ocean could result in a cooling of 2°C and “set back the tipping point of global warming from about 10 years to about 20 or more years.”

Lovelock also continues to promote the potential benefits of DMS as a check on global warming. Last year he and Chris Rapley, director of London’s Science Museum, proposed building arrays of giant pipes that would suck nutrient-rich water from the deep ocean and promote algal growth, producing more DMS as a side effect. (See Proposals Emerge To Transfer Excess Carbon to the Ocean.)

Toole and Siegel’s research into the role of UV radiation could potentially strengthen the case for algae’s role in climate control. “Based on what we’ve seen and our research, there will be more DMS,” Toole said.

As the oceans warm, the upper layer of the ocean is expected to get shallower. That means phytoplankton will be trapped closer to the surface, where they’re exposed to more UV light, stimulating more DMS. “The shallower the layer they’re trapped in, the more DMS they’re going to make,” Toole said.

Toole and some of her colleagues are currently inputting their data from the Ross Sea and Bermuda into climate models to see if an increase in DMS production is enough to affect global temperatures. But the answers are anything but straightforward, because simply adding more clouds sends complex ripples through the entire system, she says.

“If you make more clouds, you get less UV radiation in the upper ocean, perhaps leading to less DMS production by phytoplankton,” Toole said. “You get less heat, which makes the ocean less stratified, changes wind patterns, and reduces mixing. That brings fewer nutrients to the surface for phytoplankton to grow. You might get different species of phytoplankton. If we don’t fully understand the DMS cycle, it’s hard to make predictions.”

Toole, Dacey, Levine, and others will continue to ask the questions, though. One thing that’s sure about DMS: There’s still a lot to learn.

Funding for this research came from the National Science Foundation grant OCE-0425166.

Earth, Wind, and Fire in Antarctica

Earth, Wind, and Fire in Antarctica

June 25, 2008

From a windy, isolated camp in southern Victoria Land, Antarctica, three scientists from Woods Hole Oceanographic Institution explore how the waterless, lifeless, volcanic terrain formed and evolved. Read the story and watch the video.

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When you get off the plane at McMurdo Station, Antarctica, you realize what people mean by the White Continent. You, your 60 fellow passengers, and the C-17 jet that brought you here are resting on 10 feet of fresh, flat sea ice—ice that had been open water at the end of last summer. Great mountains lounge in the distance like big game on a white savannah, a flat plain of ice streaked with the gray shadows of clouds.

But you don’t really feel alone until a helicopter drops you at a field camp and leaves 10 minutes later in a cloud of blowing lava shards. When it dropped us on the slopes of Mount Morning, on Dec. 10, 2007, a stillness settled in that lasted for three days. We were five people, four tents, three working snowmobiles, two Coleman stoves, and a jackhammer, all heaped on a square of volcanic rubble the size of a basketball court. Beyond that stretched Antarctica, white to every horizon.

On the fourth day, the wind began.

In a sense, the wind was why we were there—that and the cold weather and the scrabble of young lava flows we were camping on. We were a team of three geologists from Woods Hole Oceanographic Institution (WHOI)—plus a writer and a photographer keen for a good story. We had come to this newly made ground to measure how quickly the elements tear it back down again. Our leader was geochemist Mark Kurz, the only Antarctic veteran among us; also along were volcanologist Adam Soule, a young researcher whose two favorite tools are a $10 hand lens and a $100,000 instrument called a LIDAR; and MIT/WHOI graduate student Andrea Burke, six years out of high school and 9,500 miles from her Connecticut hometown.

Much wind, no water

The volcanic landscape of Mount Morning is a story written by the wind and the cold. It doesn’t rain here, so water never runs over the rocks. And Mount Morning and the adjacent Dry Valleys region get very little snowfall, so glaciers haven’t touched most of the mountain, either. Its slopes are an angular patchwork of snowfields, lava-strewn plains, basalt pinnacles, and looming cinder cones.

“Look at this fantastic landscape,” Kurz said. “You wouldn’t have this here if there was running water.”

Just a half-mile from camp was the site of Mount Morning’s most recent eruption: Emperor Cone, a 150-meter-high pucker of cinders that never failed to remind me of a proud baboon surveying its domain.

Emperor’s latest eruption, 25,000 years ago, had rained down brick-red nuggets in sizes ranging from gumball to golf cart. Most of it had landed on the 150,000-year-old lava flow we were camped on. This older eruption had been sedate by comparison, a toothpaste-like outpouring of basalt rock colored the somber gray of a Mercedes Benz. Wind had been sculpting it ever since, chiseling pencil-sized grooves into the heavier rocks and sweeping away the lighter ones. Cold temperatures and blown snow had penetrated the porous lava, forming regular, roughly hexagonal cracks almost like frost heaves on asphalt. Seen from the air, the 20-foot-wide shapes had the look of huge reptilian scales spread across the slopes.

Kurz, Soule, and Burke were here to study the development of these “patterned ground” cracks. They were on the trail of some of the most basic questions a geologist can ask: How old is this land? How fast does it change? Isolated from the confounding effects of water erosion, these lava flows might give a clearer picture of the time it takes for wind and cold to break apart the rocks.

If Kurz’s team could estimate that, they’d have a ruler by which they could measure the age of the landscape here and in the Dry Valleys.

“And one of the reasons we want to know that,” Kurz said, “is to help settle the question of how stable the East Antarctic Ice Sheet has been.” Containing roughly half the planet’s freshwater, the 3-mile-thick East Antarctic Ice Sheet is the largest body of ice on Earth. It’s in no current danger of melting, but geologists disagree on how stable it has been in the distant past. If it has held steady for the last 15 million years, as many think, the evidence might be inscribed in the patterned ground.

A Tolkienesque landscape

That first day we set up camp in the 20ºF evening air: three teepee-like Scott tents, a kitchen tent shaped like a 7-foot tall loaf of bread, and a half-sized tent for our 5-gallon bucket of a latrine. Our lava-chunk campground proved impervious to stakes, so we guyed out our tents and anchored the lines under precarious piles of rock. We raided snow from a nearby drift to melt water, and settled in for a spaghetti dinner. Camp was only half set up, but we weren’t worried about daylight. Sunset wouldn’t come until late February.

Over the next few days we brought out the sampling equipment: First the rock hammers—sort of an extra appendage for a geologist. Kurz deployed his with no reticence. Three or four curt bashes broke off a chunk of rock, and he grabbed it for inspection without breaking rhythm. Often he found the rock dotted with tiny green crystals of olivine. Back at WHOI, he could hand-pick 100 milligrams (about four-thousandths of an ounce) of the crystals from a sample, analyze it for helium-3—a rare, light isotope of the element—and use that to determine the rock’s age.

Next, Soule brought out his LIDAR (Light Detection And Ranging), a laser scanning device used to make high-resolution, 3-D measurements over large areas. The microwave-oven-sized device mounts on a heavy-duty tripod with a motorized swiveling head. A laser, guided by precisely rotating mirrors, shoots out from the device. An equally accurate clock measures how fast the beam returns, using the elapsed time to calculate distance and elevation.

From a perch atop a lava promontory, the device (quickly dubbed the “All-Seeing Eye of Sauron” given our site’s resemblance to Mordor) can measure the size of every rock and pebble out to a distance of about 400 meters, staying accurate to less than a centimeter. After 80 minutes the LIDAR had collected some 30 million data points.

“When I was doing my Ph.D.,” Soule said, “I would walk a line over the lava and pick up every rock and measure it by hand. It took about a week.” Back home, Soule will analyze patterns in the rock sizes to complement the findings from Kurz’s age estimates.

Vibrating jackhammers and tents

To understand how the cracks form, Kurz and Soule wanted to look below the surface for evidence of churning: rocks moving gradually up and down as temperatures change day by day, season by season, decade by decade. So Soule and Burke dragged out the Wacker, our 60-pound jackhammer. Over the next four days we excavated a waist-deep trench, teaming up to hold the jittery beast steady.

This whole time the weather held, but we knew the wind was coming. For a place called Hurricane Ridge, Antarctica, it’s just a matter of time. By the fourth day all the clouds in the sky had been whisked hurriedly northward in a single creamy layer. Down on the dark rock it was still calm, sunny and warm. But over the higher ridges, quarter-mile-long plumes of snow snaked downwind.

When it came, the wind battered our tents so hard the walls knocked us off our seats. It was as if the tent itself was a film played on a jerky old projector, its outline flickering back and forth from moment to moment. Steam curled from our pot of snowmelt, then suddenly shifted 6 inches left, then back, in time with the vibrating tent walls.

Now I understood why every crack in the lava had a line of rocks arranged along it, and every crevice was jammed full of pebbles. Their varying colors—brick-red, orange-red, gray, and dark brown—suggested the volcanic plains they’d blown in from. The wind was painstakingly sorting the loose parts of the landscape like a clerk sorting letters.

Exit via helicopter

By this time it was Monday, day 8, and time for writer and photographer to leave. The wind had been steadily increasing for three days and was now a physical presence that we leaned against as we walked. The day before, during a foray over the lava, a single gust had briefly swept Kurz, Soule, and me off our feet and backwards. We probably looked like we were line dancing, badly.

Despite the weather, helicopter Zero Eight Hotel was on schedule. We gathered our things as it crept toward us from the ice shelf below. Shoving in our gear was like packing away the week itself: the stumbling over lava, wrestling with the Wacker, poring over maps, the ringing of rock hammers and the battering of tent sides, the hot breakfast cereal and cold lunches of nibbled chocolate, the rock, ice, and sky, the sun stubbornly circling our campsite. In the end, everything disappeared into the back seat, and then it was time to pack ourselves in.

We said goodbye under the rotor wash. The geologists had another 26 days ahead of them, here and at another camp nestled by the Taylor Glacier in the Dry Valleys proper. The next day was too windy for work, Kurz later told me. The day after that, gusts snapped a 2-inch-thick pole on the kitchen tent, necessitating a slapdash takedown and a scramble to batten down its contents. And the following day, after an unrelenting week of wind, the weather finally settled.

The three geologists dusted themselves off and picked up the Wacker. Over the next three weeks, they dug an astounding 11 more pits. Their rock samples are still in transit home from the ice. Back at Mount Morning, now entering a dark and bitter winter, the patterned ground is still buckling, and the wind is still scraping away at the mountain.

This research was funded by the National Science Foundation.

Popular Way to Assess Oil Spills Can Be Misused

Popular Way to Assess Oil Spills Can Be Misused

May 28, 2008

Environmental assessment teams increasingly may be using a method to assess oil spill contamination in situations where it doesn’t work well and are in danger of reaching false conclusions, a scientist at Woods Hole Oceanographic Institution has warned

In a letter published online April 30 in the Marine Pollution Bulletin, marine chemist Christopher Reddy issued what he called “a cautionary tale” about using the “pom-pom” method as a universal practice for assessing oil contamination in ocean- or river-bottom sediments. The method uses long strands of absorbent polypropylene swabs, which look like cheerleaders’ pom-poms, dragged along bottom sediments. The method is in demand because it offers a rapid, low-cost way to locate large areas where oil has sunk to the sediments. But that doesn’t mean it can effectively identify lesser amounts of oil that can have harmful impacts on ecosystems and public health, Reddy said.

Reddy pointed to the spill of 58,000 gallons of heavy fuel oil after the M/V Cosco Busan struck the San Francisco-Oakland Bay Bridge in November 2007. In late December, the pom-pom method was used to assess whether sediments dredged near the Port of Oakland could be safely used to help restore a tidal wetlands.

“The problem may stem from an unfortunate misinterpretation of research following a spill of the M/T Athos I in the Delaware River in 2004,” Reddy wrote. In that case, responders used a boat to drag several beams with pom-poms across sediments on the riverbed. Back on deck, personnel could see whether the pom-poms came up white and clean or black and oil-stained and could quickly determine the locations of large oil patches on the river floor. The information proved valuable for putting together the best emergency response and cleanup, Reddy said.

“But the method was never intended to assess contamination at much lower, but still significant levels,” Reddy wrote. “A great tool for the circumstances of the Delaware River oil spill does not translate to the conditions in San Francisco Bay.”

In the Port of Oakland, the U.S. Army Corps of Engineers used the pom-pom method to look for evidence of tar balls that may have sunk to the sediments after the M/V Cosco Busan spill. Finding none, the Corps declared the dredged material safe and used it in the restoration project.

“This approach is flawed,” Reddy wrote. “It relies on the assumption that the lack of visible oil on the (pom-poms) … indicates a total lack of oil contamination in the sediment.”

Without any detailed testing to determine the pom-pom method’s ability and sensitivity to attract oil under various conditions and circumstances, “it is not possible to determine that the  (Port of Oakland) sediment was not contaminated with oil at unacceptable levels,” Reddy said in an interview. “The absence of evidence is not evidence of absence.”

“Before this approach becomes standard practice for determining whether sediments have been contaminated at levels that may impact ecosystems, prudence dictates much more rigorous testing of the test itself,” Reddy wrote in Marine Pollution Bulletin. “When considering analytical methods used following any oil spill, the selectivity and sensitivity should match the objectives and required information.”

In a reply to Reddy article in Marine Pollution Bulletin, Robert Lawrence, chief of dredged material management for the Army Corps’s San Francisco District, acknowledged that Reddy is correct that “the (pom-pom) test is not meant to be looking for low levels of contaminants.”

“It’s meant for gross contamination,” Lawrence said. “The swabbing test needs to be tested further if it is to be incorporated as a be-all” used to assess various oil-spill situations.

In the specific case of the Port of Oakland, Lawrence said, the spilled oil was light enough to float atop the water. Analysts for the Corps believed the oil would sink to the sediments only if it coagulated into larger, heavier tar balls, so that the probability of finding less-than-gross oil contamination was unlikely. Further, if oil had sunk to the sediments, the Corps’s analysts thought it was too soon after the spill for the oil to break down and get into the sediments at lower levels, he said.

The research was funded by the Richard and Rhoda Goldman Fund and the Coastal Ocean Institute at WHOI.