Impacts of Ocean Acidification on Pteropod Physiology
Ann Tarrant, Amy Maas, Gareth Lawson
Dissolution of excess CO2 produced by humans into the ocean is causing the marine environment to decrease in pH. This ‘ocean acidification’ is predicted to threaten a broad variety of marine taxa, particularly calcifying animals such as the thecosome (shelled) pteropods. Pteropods, commonly referred to as sea butterflies or pelagic snails, are a group of gastropods that are found throughout the world’s oceans and are important contributors to the biogeochemical cycle of carbon and marine food webs. To predict the effects of hypercapnia (high CO2) on pteropods,
We must understand the physiological mechanisms through which pteropods can respond to high CO2 and the natural variability in pteropod exposure to this environmental stressor. It is our goal to expose pteropods from the North Atlantic and North Pacific Oceans to conditions mimicking predicted CO2 levels at the end of the century and to compare physiological responses of pteropods from these different ocean environments. The hydrographic profile of these two ocean basins provides a natural experiment, with low CO2 concentrations at depth in the Atlantic, and elevated CO2 concentrations conditions at depth in the Pacific. Using metabolic assays and sensitive molecular indicators we will determine how exposure to elevated CO2 differentially affects acid-base balance and metabolism between closely related thecosomatous pteropods from the two ocean basins.
Sentry-mounted Sidescan Sonar Imaging of Kermadec Arc Volcanoes
Volcanic arcs are the surface expression of subduction related magmatism. Intraoceanicarcs – those built upon oceanic crust – with a submarine component total 22,000 km inlength, ~1/3 the length of the global mid-ocean ridge (MOR) system. Submarine arcsproduce isolated volcanoes/seamounts with greater potential for explosive eruptions thanMOR volcanoes. The shallow depth and sediment-free summits of many arc volcanoesmake them important oases for chemosynthetic and benthic animal communities andfisheries. In addition, submarine arc volcanoes host long-lived and robust hydrothermal circulation that produces the largest mineral deposits preserved in the rock record. Arcmineral deposits are richer in precious metals (Gold, Silver) than those on MORs, and with their shallow depths and position along the margins of the ocean basins, mining of these deposits is likely to become economically viable in the coming decades.
This proposed work seeks to evaluate the relationship between explosive and effusive volcanic eruptions, regional and local faulting, and hydrothermal discharge to volcano development and seafloor mineralization at three Kermadec Arc volcanoes. To do so, I will utilize the first near-bottom sidescan sonar data ever collected on arc volcanoes. These sidescan sonar data, along with co-located subbottom profile data and seafloor photographs, will allow me to identify the size, type (explosive/effusive), and relative age of volcanic deposits, sedimentary deposits, and faulting on the volcano summits and flanks. The level of detail (sub-meter resolution) and coverage (volcano summits and flanks) provided by these data are unique for arc volcanoes and fill a crucial gap in our knowledge between large-scale arc volcano morphology and highly localized submersible observations. Construction of detailed geologic maps will allow me to test hypotheses regarding volcano growth, caldera development, and subsequent hydrothermal discharge localization proposed for arc volcanoes that have significant implications for the modes of mass and heat transfer and chemical exchange at convergent margins.
This proposal will facilitate my collaboration with NDSF on the development of processing and acquisition best-practices for the new AUV-based sidescan sonar system. Several proposals, including one of my own, were submitted to the most recent NSF panel to use this pending capability of Sentry. The success of theses and future proposals for Sentry-based sidescan sonar mapping will depend on a demonstration of the effective use of these sensors in real-world settings, which is an important goal of this research.
This work also represents collaboration with Institute of Geological and Nuclear Science (GNS - New Zealand) scientists with whom WHOI has recently (2010) signed a memorandum of understanding and who have strong scientific and national interests in the Kermadec Arc. This project will investigate a small, but important data set that will open new avenues of seafloor exploration for arc volcanoes and lead to future proposal development with GNS colleagues for investigating magmatic and hydrothermal processes in the Kermadec Arc.
A Cable-free Mooring Platform for Imaging FlowCytobot
Continuous, extended time series are needed to investigate the responses of marine ecosystems to environmental changes on different time scales, so Heidi Sosik and I have developed an automated submersible flow cytometer, Imaging FlowCytobot (IFCB), which is capable of longduration, high-resolution analyses of nano- and microplankton cells such as ciliates, diatoms and dinoflagellates. Cells in this size range often have distinctive morphology that allows them to be identified to genus or even species by our automated image processing/classification system. For the past several years IFCBs have been deployed at the Martha’s Vineyard Coastal Observatory (MVCO) and at the entrance to an estuary on the Texas Gulf Coast, and the near-continuous stream of data and images of individual cells is providing an unprecedented view of the plankton (as well as timely warnings of several blooms of toxic dinoflagellates).
IFCB currently uses a cable from shore for power and communications. We would like to enable IFCB to be deployed at non-cabled sites as well; our ultimate goal is deployment on buoys being developed for the Pioneer Array of the Ocean Observing Initiative (OOI). As a step towards this goal, we propose a non-cabled, moored deployment of IFCB in Salt Pond (Nauset, MA), where D. Anderson and others have been studying bloom dynamics of the toxic dinoflagellate Alexandrium tamarense. The development and testing of the proposed mooring will serve 2 purposes: It will help identify problems in operation of the instrument on a mooring as opposed to a fixed structure, and in power and communications for non-cabled operation; and it will provide a detailed record of plankton diversity in Salt Pond, which will enhance current work by other WHOI scientists studying this system.
Unmanned Aerial Systems for Oceanographic Applications
Hanumant Singh, Stephanie Jenouvrier
Aircraft and helicopters continue to play vital roles in the oceanographic sciences. However, there are a number of oceanographic applications where these large, expensive, loud, and hydrocarbon fuel based platforms can be replaced with far simpler, cheaper and cleaner unmanned airborne assets.
This proposal is aimed at demonstrating a proof of concept for an Unmanned Aerial System (UAS) specifically designed for scientific oceanographic applications. In particular we aim to outfit an inexpensive large scale model aircraft with navigation, attitude and other sensors to enable a variety of diverse oceanographic applications including surveying penguin colonies in Antarctica; looking at very shallow water coral reefs in Puerto Rico; atmospheric measurements of CO2 at the air sea interface and for marine mammal surveys in the New England area.
While the airframe has been successfully deployed and tested locally in Woods Hole, this proposal will demonstrate the two components that are critical for the types of applications outlined above. Firstly, that the UAS can be deployed and recovered from very confined spaces such as the deck of the R/V Tioga and secondly, that the UAS can be successfully operated by non-specialist scientific personnel with minimal flight training.
Enhancement of MVCO Ocean Observing System Web Services
New standards-based technologies (OGC/W3C) have enabled the delivery of observational data through web services. A well-described system of interdisciplinary sensors can demonstrate best practices in providing sufficient information to assess shared data quality. With funding from a NOAA-IOOS award, the MVCO ADCP waves system is now being offered through an OGC Sensor Observation Service, fully-described for quality assessment. This work demonstrates best-practices in serving standards-based observational data through web services. Through support from this award, SensorML profiles will be developed that can be used as a template by anyone serving CTD, in situ current profiles, wind, air temperature, air pressure and relative humidity data. These will be integrated into the SensorML MVCO ocean observatory profile, making WHOI the only standards-based web service offering access to complete operational observatory profile. Currently, other implementations of web services provide only basic information about the data (format, units of measure, data provider), they do not provide integrated metadata nor is there description of the complete observatory platform. Support requested here will be used to develop and promote the implementation of well-described observational systems adding value to the data beyond the original intended use and providing a means to enable dynamic quality assessment of archived and real-time observations, making WHOI a leader in the development of methods to enable QA/QC integration in the nation’s observing systems.
Measuring Ocean Waves Remotely from a Moving Underwater Vehicle
Surface waves are a central player in a wide range of ocean processes of scientific, engineering and societal importance. Examples are air-sea interaction, where they mediate the fundamental mechanical coupling between the wind and the interior water column, and the suspension and alongshore transport of sand and sediment, which drive changes in coastal morphology. Knowing the heights, periods and directions of the longer (energetic) waves also is important for the control of underwater vehicles, such as submarines – for example, when coming to and operating at, periscope depth (the latter application is of particular interest to the 2nd author of this proposal who is an active duty submariner in the U.S. Navy and has experienced the control problem firsthand).
However, despite their importance, ocean waves have been notoriously difficult to measure, typically requiring specialized instrumentation costing many tens of thousands of dollars. This has tended to discourage investigators from measuring waves, except in special circumstances, and as a consequence they are not routinely measured, even in the coastal ocean where they are particularly important. Over the past decade, however, there has been considerable progress in developing a new method of measuring wave height and direction using acoustic Doppler current profilers (ADCPs). These instruments, originally developed to profile currents remotely, are widely used in coastal oceanography, and several vendors now offer relatively inexpensive extensions to enable ADCPs also to measure waves. At present, however, the latter application requires that the instrument be rigidly fixed to the bottom, pointing upward, and hence limits the approach to relatively shallow, near-shore regions.
Consequently, there is considerable interest in extending the technique to enable the measurement of ocean waves remotely from subsurface moorings and underwater vehicles. The technical impediment to this is that the subsurface float (or vehicle) will move in a wave-correlated way in response to the wave forcing, and hence the velocities measured by the ADCP will be biased. Underwater vehicles present an additional difficulty in that the waves are Doppler shifted by the forward motion of the vehicle.
In conjunction with the 2nd author's thesis work, we are developing new algorithms to overcome these problems and to enable estimation of the frequency-direction spectrum of surface waves using ADCP measurements from a moving underwater platform. Somewhat surprisingly, we have not been able to discover a set of observational data, including ground-truth measurements of the waves, suitable for testing them. Consequently the focus of this proposal is to carry out an experiment to generate such a data set, and to test and validate the performance of our algorithms on it. The field experiments will use a REMUS-100 autonomous underwater vehicle equipped with upward- and downward-looking ADCPs and a high quality inertial motion-sensing package. We will operate the REMUS around the 12 m underwater node at the Martha's Vineyard Coastal Observatory. This node has an upward-looking ADCP that will provide comparison measurements against a fixed instrument (the REMUS and node ADCPs are essentially identical). Ground truth will be provided by a conventional moored wave directional buoy. We plan 5 days of field observations in order to capture a range of wave conditions. This experiment is expected to generate a unique data set for testing approaches to measuring waves from moving subsurface platforms using ADCPs, and will be a central part of S. Haven's MS Thesis.
Mechanical Properties and Seismicity of East Coast Submarine Landslides
John Collins, Jeffrey McGuire, Uri Ten Brink
The Atlantic continental margin is an area with relatively few earthquakes, but there is still the possibility of significant damages. For instance, the M7.2 1929 earthquake along the continental slope of Nova Scotia, caused a large-area landslide (22,700 km2), which generated a devastating tsunami (up to 8 m in amplitude and 13 m of runup). The Atlantic coast is vulnerable to tsunamis because of the large infrastructure and population concentrations along the coast, including on barrier islands and estuaries. The primary potential tsunami sources for the U.S. Atlantic coast are likely submarine landslides. ~90% of landslide-generated tsunamis worldwide are associated with earthquakes. Recently we have shown that the observed size distributions of landslides along the Atlantic margin can be generated if we assume that the landslides were generated by earthquakes with magnitudes 4.5-7.5. In 2012, the USGS Woods Hole group led by ten Brink will conduct an ocean bottom seismometer experiment using WHOI instruments to study the microseismicity of the slope and upper rise in a region of mapped landslides south of Martha’s Vineyard and downslope of the Pioneer Array. This project will aim to characterize the physical properties of the landslide material via the innovative use of ambient noise recorded on the OBS and to locate microseisms from active faulting that may trigger slides. This DOEI/Access-to-the-sea proposal requests funds to allow Collins and McGuire to participate in the cruises and data analysis from this project.