2009

Mid-Cayman Rise study area.

Overview

This October a renowned team of oceanographers and astrobiologists will explore one of the deepest points in the Caribbean Sea, searching for life in extreme seafloor environments. Using the new hybrid underwater robotic vehicle Nereus, these scientists will extend their investigations beyond the reach of other research submersibles to the bottom of the Mid-Cayman Rise, whose maximum depth is just over 6,800 meters (4.2 miles) deep.

The study area, also known as the Mid-Cayman Spreading Center, is one of Earth’s deepest and slowest-spreading mid-ocean ridges—regions where two of Earth’s tectonic plates are ripped apart and new material wells up from the Earth’s interior. There, scientists will search for hydrothermal vent systems—natural, seafloor plumbing systems where cold seawater circulates down into the hot, freshly-formed oceanic crust releasing heat and mineral-rich fluids at the seafloor that support complex ecosystems of exotic organisms.

By exploring this extreme and previously uninvestigated section of the Earth’s deep seafloor, this research seeks to extend our understanding of the limits (in terms of extreme environments) to which life can exist on Earth and to help prepare for future efforts to explore for life on other planets.

A detailed bathymetric base map of the Mid-Cayman Rise study area.  The 32 round targets show locations at which scientists plan to stop and sample the water column using the CTD—every 5 miles along and across axis, to complete a thorough survey for hydrothermal activity.

Where is the Expedition?

The Mid-Cayman Rise lies in the middle of the Cayman Trough (or Cayman Trench) which is located in the western Caribbean Sea, south of Cuba and Jamaica and close to the Cayman Islands. In the middle of the East-West trending Cayman Trough lies the Mid-Cayman Spreading Center—approximately 110 kilometers (68 miles) long and spreading apart at an ultra-slow rate of less than 20 millimeters (0.9 inches) per year.

Why Study this Area
Ultra-slow spreading ridges such as the Mid Cayman Spreading Center make up about 25 percent of the 60,000-kilometer (40,000-mile) long system of mid-ocean ridges that encircle the globe. Until recently, these ultra-slow ridge systems remained almost completely overlooked, because of an early hypothesis that their slow spreading rates would make hydrothermal activity rare or absent. This hypothesis has since been disproved and surveys along ultra-slow ridges in the Southwest Indian Ocean and the Arctic have shown that, on average, at least one vent site occurs approximately every 100 kilometers (60 miles) along the axis of these ridges.

While no hydrothermal exploration of the Mid-Cayman Spreading Center has previously been carried out, dredging and submersible studies along the walls of the rift valley have identified locations where rocks have been extensively altered hydrothermally. The discovery of these rocks, as well as the hydrothermal activity found on similar spreading centers, makes researchers optimistic that they will discover active hydrothermal vents in the Cayman Trough.

If the science team does find hydrothermal systems at such great depths, their discovery will likely extend the known limits to life on our planet in terms of pressure, temperature, and vent fluid chemical compositions. And because hydrothermal circulation can arise on any planet that currently has, or has experienced, liquid water and a source of heat, this new research along the Mid-Cayman Rise can provide new insights into the possible origins and evolution of Earth’s biosphere, as well as the conditions that might have given rise to comparable life-forming chemicals and/or life on other worlds.

R/V Cape Hatteras

The 41-meter (135-foot ), steel-hulled research vessel Cape Hatteras is owned by the National Science Foundation and operated by the Duke/University of North Carolina Oceanographic Consortium. It has a cruising speed of 10 knots and can stay out at sea for up to 25 days.
» Learn more about the R/V Cape Hatteras

Take an Interactive Tour of Nereus to learn more.
"> » Take an Interactive Tour of Nereus to learn more.

HROV Nereus

HROV Nereus, built and operated by Woods Hole Oceanographic Institution engineers, is an unmanned vehicle that operates in two complementary modes.  It can swim freely as an autonomous underwater vehicle (AUV) to survey large areas of the depths, map the seafloor, and give scientists a broad overview.  When Nereus has located something interesting (for example, on this cruise we hope to find completely new and unexplored vent-sites) it can be brought back on board the ship and transformed into a remotely operated vehicle (ROV) tethered to the ship via a microthin, fiber-optic cable. Through this tether, Nereus can transmit high-quality, real-time video images back to skilled pilots on the ship, who can send commands to the vehicle to collect samples or conduct experiments with a manipulator arm.

For this expedition, Nereus will first operate in AUV mode.  After using the CTD to survey the area for hydrothermal plumes, researchers will deploy the AUV to locate, map, and photograph hydrothermal vents, at the seafloor. To do this, the Nereus operation team will first relocate each plume and home in to its source. The AUV will then descend close to the seafloor to obtain detailed bathymetry of the target site and intercept buoyant plumes from any high-temperature vents present.  Lastly, the vehicle will be programmed to photo-mosaic individual vent sites and any ecosystems they host.

After operations in AUV mode, the vehicle will be converted into ROV mode for the last phase of the expedition.  By this stage (Leg 2 of the cruise) we will also be ready to welcome a whole new set of specialist scientists on board.  In ROV mode, Nereus will have up to eight hours of sampling per deployment at any vent site we have found – or other areas of interest.  The vehicle will perform a combination of geochemical and biological sampling of vent fluids, minerals, hydrothermally altered rocks, large volume filtration (to sample chemicals or microbial life in the vent fluid) and extensive sampling of any megafauna.
» Learn more about Nereus

Conductivity, Temperature, and Depth (CTD) Sensor

The first phase of the expedition will be to search for the plumes that rise up above hydrothermal vent sites using a Conductivity, Temperature, and Depth (CTD) sensor.  Buoyant, high-temperature plumes of fluid emanating from hydrothermal vents contain high concentrations of iron, manganese, and methane and rise hundreds of meters above the seafloor before being dispersed laterally by deep-ocean currents. It is the CTD’s job to detect temperature and other physical signals generated from the plumes and to collect water samples that will be analyzed on-board the ship as well as back in the lab after the cruise.

The CTD instrument package hangs from a conducting cable that is lowered vertically beneath the ship.  Arranged around this instrument pack in a rosette are a series of 24 sampling bottles that are open top and bottom with snap-shut caps.  As the instrument package is lowered to the seafloor, the various sensors send readings back, in real time, to a computer on the ship. Scientists monitor how the composition of the ocean changes at increasing depth from the surface to just above the seafloor and use the data sent back to the ship to map hydrothermal signals detected in the water column above the seafloor.  Then, as they haul the instrument package back up through the water column, they can choose where to take samples by using the top-side computer to send an electrical pulse down the same conducting cable that brings the data to the surface.  Each pulse triggers a sample bottle on the CTD frame, one bottle at a time, so that the end-caps snap shut and a water sample is collected at exactly the depth required.  When the CTD and water sample bottles are hauled back on the ship, the scientists transfer the water samples to the ship’s laboratory where they perform analyses to identify hydrothermal chemicals.
» Learn more about CTD's

Dates

October 7 - October 26: First leg of expedition.  CTD and Nereus AUV operations
October 27 - October 28: Port call, Georgetown, Cayman Islands.  Nereus switches to ROV mode
October 29 – November 6: Second leg of expedition.  Nereus ROV operations

Funding

This expedition is funded by NASA’s Astrobiology Science and Technology for Exploring Planets (ASTEP) program.

Dr. Christopher R German

Chief Scientist for Deep Submergence, Woods Hole Oceanographic Institution

My interests are three-fold. First, from a geological perspective, I am interested in where hydrothermal vents occur on the seafloor and why. Second, I am interested in the impact that hydrothermal systems have on ocean chemistry. Finally, I am interested in how the settings of hydrothermal vents and their global-scale distributions, along with those of other chemosynthetic habitats, have given rise to the patterns we observe today in the distributions of fauna that inhabit vents around the world.

On this expedition I am the Chief Scientist and lead PI for the NASA proposal that brought the team together.  As well as having led a series of cruises in the past using "established" techniques to find vents—using both CTD-rosette systems and deep-tow geophysical instruments equipped with in situ hydrothermal sensors, I have pioneered the use of using AUVs to drill down even further from finding first plume signals to the point where we can actually locate and photograph hydrothermal fields in previously unexplored ocean basins.  To-date we have found approx 16 different hydrothermal fields using this approach over 5 expeditions, including the first vents ever found in the southern Atlantic Ocean and the first vents to be identified on the ultra-slow spreading SW Indian Ridge.

During Leg 1 of the cruise my role will be to run one of the two watches conducting 24 hour operations with the CTD and to work with the Nereus AUV team if any evidence of a hydrothermal plume is detected.  During Leg 2, I will be overseeing dive operations and work with the Leg 2 scientists to identify priorities for what sampling equipment gets carried to the seafloor by Nereus and what sampling gets done.

Dr. Julie Huber

Assistant Scientist, Marine Biological Laboratory

My lab studies the microbiology of deep-sea hydrothermal systems and focuses on the distribution, diversity, and physiological adaptations of microbial groups at hydrothermal systems. Microorganisms from this environment offer opportunities to study many exciting aspects of marine microbial ecology, including molecular evolution, astrobiology, microbial diversity, and biogeography.

I am leading the microbiological portion of the ASTEP program. The MCSC is an ideal natural laboratory in which to examine two key understudied aspects of vent microbiology: ultramafic-hosted microbial communities and those at great depth (>3500m). We will do microbiology on any and every sample that comes on deck: water from CTD casts, rocks, sediments, microbial mat, vent fluids, even animal surfaces. All samples will be analyzed using a suite of molecular, microscopic and enrichment-based techniques to examine the adaptation of microbes to their geologic and chemical habitat.

Mr. Andrew Bowen

Research Specialist, Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution

Andy has been involved in the development, design and operation of unmanned underwater robotics. He also manage the National Deep Submergence Facility, based at Woods Hole. This facility is made up of the human occupied submersible Alvin, the tethered vehicle Jason and the autonomous vehicle Sentry. I continue to be involved in the development of new submersible vehicles like Nereus.

Andy is on the expedition to help keep Nereus operating. In particular, He will work with the science team to help plan how we can best use Nereus to achieve the goals of the expedition. He will help on deck and work with the other members of the team to ensure Nereus is ready to go.

Dr. Max Coleman

Senior Research Scientist, NASA Jet Propulsion Laboratory, Caltech

Max looks for Life outside the Earth. His research focuses on identification of minerals that formed as result of, or in the presence of, biological activity and developing instruments that could detect them. He is on the expedition because he is a card carrying ASTROBIOLOGIST and the Mid-Cayman Trough location is the best terrestrial analogue for the deep hydrothermal vents believed to exist (under thick ice at the bottom of a salty ocean) on the moon of Jupiter, Europa. It will allow us to develop the protocols for autonomous search for hydrothermal vents on Europa and subsequent detection of Life associated with them.

Max's roles on the expedition are to use mineral compositions to understand present and past fluid compositions as sources of energy for living organisms and to quantify the amount of life such energy could support. He will try to ensure that appropriate mineral samples are recovered, curate them and analyze them subsequently at JPL.

Dr. Douglas P Connelly

National Oceanography Centre, Southampton, UK

Doug is a geochemist from NOCS who spends a lot of time at sea looking for exciting new vent sites. When he is not at sea he helps to develop chemical noses to sniff out the signals of vents over very long distances. In the past few years he has been to the Atlantic, Pacific and Indian Oceans hunting for sites but this is his first time hunting in the Caribbean.

I will be running the CTD with Chris and hunting the vent sites using the LSS. We will collect samples for the onboard analysis of dissolved methane and return samples back to our lab in the UK for the analysis of manganese and iron, important tracer species for hydrothermal vent inputs.

Mr. Phil Forte

Mechanical Engineer, Deep Submergence Lab, Woods Hole Oceanographic Institution

Phil's area of expertise is mechanical design for crewed and uncrewed submarines such as Alvin and Jason. Previously, he was an Alvin pilot and currently participates in at-sea operations with Jason. Phil is on the expedition to support all mechanical aspects of the vehicle, launch and recovery, and watch standing as a pilot.

Mr. Daniel Gomez-Ibanez

Engineer, Woods Hole Oceanographic Institution

Daniel studies underwater engineering, especially vehicle batteries and propulsion. During the cruise, he will endeavor to make everything work, and to streamline the flow of matter and information, transforming Nereus from a promising idea into an operational vehicle. Daniel will be part of the team operating Nereus, managing battery charging and energy use, and supporting a variety of sensors and samplers integrated with the vehicle He will be on both the AUV and ROV legs.

Mr. David Honig

Graduate Student, Marine Laboratory, Nicholas School of the Environment, Duke University

I study the role invertebrates play in the transfer of energy from geosphere to biosphere at deep-sea hydrothermal vents. Only microbes can build biomass via chemosynthesis, so invertebrates exploit the energy available at vents by either directly or indirectly consuming microbial primary production. I will work with Dr. Van Dover and Dr. Coleman to answer the following questions: How do feeding strategies of Cayman Rise invertebrates reflect evolutionary history and underlying geology? How do these invertebrates influence cycling and dispersal of chemosynthetically-fixed carbon? I will spend the second leg of this cruise either glued to the Nereus video stream or dissecting and preserving invertebrates brought back to the surface.

Dr. Mike Jakuba

Post-doctoral fellow, Australian Centre for Field Robotics, Sydney, Australia.

Dr. Jakuba's research interests revolve around deep sea robotics. Of particular relevance to the present cruise, he designed the AUV-configuration flight controllers for Nereus; and as a graduate student developed novel mapping algorithms for the autonomous localization of hydrothermal venting. He will be on board during the first leg to tune flight controllers and terrain-following algorithms used by Nereus to fly above the seafloor. He also hopes to improve the chances of rapidly finding seafloor vent sites by employing real-time data-driven search strategies to modify the vehicle's flight path when water-column chemical data suggests proximal venting.

Ms. Jill McDermott

MIT WHOI Joint Program Student, Woods Hole Oceanographic Institution

I study the chemistry of deep-sea hydrothermal vents and am a graduate student working with Dr. Seewald and Dr. German. I am interested in the inorganic, organic, and dissolved gases in these fluids, and in how they support thriving ecosystems. I will be working with fluid samples on leg two of this cruise, conducting time-sensitive measurements on-board the ship and preparing the samples for further analysis in the shore-based laboratory.

Dr. Ko-ichi Nakamura

Senior Research Scientist, IGG, Seafloor Geoscience Research Group, National Institute of Advanced Industrial Science and Technology (AIST), Japan

Ko-ichi studies marine geology and hydrothermal and gas hydrate studies in various settings. In other words, fluids emission from subseafoor, cause, process and results, which includes fluid behavior in the water column as well as on the seafloor. He is on the expedition because he has been interested in the Caribbean geology and the Cayman Trough tectonic process since 1978. He is expecting the discovery of new type of hydrothermal system in one of the most deepest and slowest-spreading ridge in the world. On the trip Ko-ichi will chase the hydrothermal plume by electrochemical sensor (Eh sensor) both on CTD and the Nereus. He will also maintain the electrode and interpret data for the chasing efforts.

Dr. Carla Sands

National Oceanography Centre, Southampton, UK

I study the chemistry of hydrothermal plumes. In particular I'm interested in the fate of iron and other metals that tend to be closely associated with iron in hydrothermal plumes. I'll be on the 1st leg of the cruise, helping to collect water samples from the CTD casts. On board ship, I'll be measuring the dissolved methane in these samples and later back in the lab, determining the dissolved iron and manganese concentrations.

Dr. Jeffrey Seewald

Senior Scientist, Woods Hole Oceanographic Institution

Jeff studies vent fluid chemistry. He is on the expedition to understand geochemical processes that regulate the organic and inorganic chemistry of axial hot-springs. Jeff will be collecting hydrothermal vent fluids and analyzing theme onboard ship for a variety of dissolved gases and pH. Other chemical species will be analyzed in shore based laboratories.

Dr. Julie Smith

Postdoctoral Scientist, Marine Biological Laboratory

I am a marine microbial ecologist interested in how microorganisms respond to and interact with their environment and how environmental stressors shape microbial genomes and transcriptomes. On this expedition, I will be assisting Dr. Huber in the investigation of microbial communities found in any samples retrieved from the Mid Cayman Spreading Center. We will be looking at the community DNA to find out "who" is there and looking at the community RNA to find out "what" they are doing in terms of the genes that they are using. In addition, we will perform enrichments of samples from the sea floor to try to grow some of these microorganisms in the lab.

Mr. Sean Sylva

Research Associate III, Woods Hole Oceanographic Institution

Sean's research mainly focuses on novel approaches to measure the stable isotopes of light hydrocarbons found in hydrothermal vent fluids. He is part of the CTD team on this expedition and is in charge of the Gas Chromatograph instrument that will be used to measure the concentrations of methane in all water column samples brought aboard ship to help locate any hydrothermal vent fields that may occur along the Mid-Cayman Rise.

Mr. Chris Taylor

Research Engineer, Woods Hole Oceanographic Institution

Chris's interests are underwater vehicle systems engineering and technology. He is part of the Nereus design team, responsible for overall electrical system design and integration. During this expedition, his focus is to operate, analyze, test and troubleshoot Nereus electrical and fiber optic systems and sensors. As well as any troubleshooting needed at sea, Chris will also be part of the watch team that monitors, navigates, and pilots Nereus during dive missions in both AUV and ROV mode.

Ms. Tina Thomas

R/V Cape Hatteras Marine Technician

Dr. Cindy Lee Van Dover

Director, Marine Laboratory, Nicholas School of the Environment, Duke University

This is my dream expedition.

Dr. Louis Whitcomb

Professor, Departments of Mechanical Engineering and Computer Science Director, Laboratory for Computational Sensing and Robotics Johns Hopkins University
Adjunct Scientist, Woods Hole Oceanographic Institution

Robotics. Louis is an engineering professor. His research is the development of novel robotic underwater vehicle systems and technology to enable new methods of ocean science that are presently considered impractical or infeasible.

Louis is Co-Principal Investigator (with Andy Bowen and Dana Yorger) on the development of the Nereus hybrid underwater vehicle. The goal of the Nereus project is to provide the U.S. oceanographic community with the first capable and cost effective vehicle for routine scientific survey, sea floor and water-column experimentation, and sampling to the full depth of the ocean of 11,000 m—significantly deeper than the depth capability of all other present-day operational vehicles. I am also a co-PI on the Oases expedition, where we plan to utilize Nereus to perform large-area survey and fine-scaled sampling at depths to about 7,000 m the Mid-Cayman Trough.

Louis's focus on this expedition is to work withour engineering/science team to develop and test Nereus’s capabilities of performing autonomous scientific survey missions. Nereus operates in two different modes. For broad-area survey, the vehicle can operate untethered as an autonomous underwater vehicle (AUV) capable of exploring and mapping the sea floor with sonars and cameras. Nereus can be converted at sea to become a remotely operated vehicle (ROV) to enable close-up imaging and sampling. The ROV configuration incorporates a lightweight fiber-optic tether for high-bandwidth, real-time video and data telemetry to the surface enabling high quality teleoperation. The first leg of the Oases expedition will employ Nereus to perform surveys in AUV mode. The second leg will employ Nereus to perform sampling and close-up observation on the sea floor in ROV mode.

Dr. Dana Yoerger

Senior Scientist, Woods Hole Oceanographic Institution

Dana has been working on remotely and autonomous vehicle since coming to WHOI in 1984. Working with Chris German, Ko-ichi Nakamura, Doug Connelly and others, theye made the first discoveries of hydrothermal vents using an autonomous vehicle (the Autonomous Benthic Explorer, ABE) in 2004 in the Eastern Lau Spreading Center near Fiji and Tonga. They also made the first vent discoveries on the Southern Mid-Atlantic Ridge (2005) and the Southwest Indian Ridge (2007) using ABE. Dana will be working on the mission programming, control system, navigation, and map-making for Nereus. Finding vents in the mid-Cayman Rise represents their biggest challenge yet.