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Kristen N. Buck
Kristen N. Buck

Dr. Kristen Buck

Research in the Buck lab is geared toward investigating the biogeochemical cycling of trace metals in the oceans and, in particular, the role of organic ligands in the bioavailability and cycling of the bioactive trace metals iron and copper.  Buck’s research in the Southern Ocean is directed primarily at improving understanding of the chemistry of iron, which serves as a limiting nutrient to phytoplankton in these waters. An ongoing collaboration with Bethany Jenkins (URI) and Dreux Chappell (ODU) is designed to investigate the feedback interactions between phytoplankton communities, nutrient conditions, and the physicochemical speciation of iron in the open waters of the Antarctic Circumpolar Current, as compared to the coastal waters of the West Antarctic Peninsula. This current work is funded by the National Science Foundation and employs a combination of field sampling, shipboard incubation experiments, and laboratory-based manipulation experiments. Contact Dr. Kristen Buck

Don P. Chambers
Don P. Chambers

Dr. Don Chambers

Dr. Chambers, his students, and research staff study several aspects of the changing physical state of the Southern Ocean and Antarctica, including: sea level contribution from Antarctica ice sheet melting, changes in the circulation of the Antarctic Circumpolar Current over time-periods of several years to a decade or longer, long-term changes in the eddy kinetic energy throughout the Southern Ocean, and identification of fronts and jets in the Southern Ocean. They mainly use satellite data (altimetry, gravity, winds, and sea surface temperature), but also use data from in situ observations including the Argo array, CTDs, tide gauges, and bottom pressure sensors. Contact Dr. Don Chambers

 

Tim Conway
Tim Conway

Dr. Tim Conway

Research in Tim Conway’s group aims to understand the geochemistry of trace metals in the marine and earth system, and the role they play as micronutrients and/or toxins in marine biogeochemical cycles, with effects on the global carbon cycle. Researchers working with Dr. Conway employ isotopic techniques including measurement of trace metal (Fe, Zn, Ni, Cd, Cu) isotope ratios by multi-collector HR-ICPMS in a range of materials including aerosol dust, rocks, sediments rain, seawater, ice-cores, marine particles and biological materials. We work closely with national and international collaborators as part of the International GEOTRACES program, working on seawater and other samples collected from all over the world. Our current Southern Ocean work focuses on the importance of margin and hydrothermal sources in supplying Fe to the vast Fe-limited Southern Ocean, and also how biological processes, mixing and physical upwelling in the region impart distinctive preformed signatures on the trace metals isotope signatures to newly formed water masses such as Antarctic Surface Water and Antarctic Intermediate Water. These water masses then carry these signatures north to the low-latitude oceans. We have recently participated in the Swiss-led Antarctic Circumnavigation Expedition and also Japanese GEOTRACES cruise GP19. Contact Dr. Tim Conway

Kendra L. Daly
Kendra L. Daly

Dr. Kendra Daly

Dr. Daly has investigated questions related to polar marine ecosystems for more than three decades.  Her group seeks to improve understanding of the ecology and physiology of polar marine organisms, including their role in biogeochemical cycles, their interactions within the marine food web, and community dynamics in relation to their environment. For example, studies include the overwintering physiology and survivorship of Antarctic krill in relation to sea ice and the role of bottom-up and top-down forcing on the marine food web in McMurdo Sound, which is one of the few places on the planet with relatively undisturbed top predator populations. These investigations have addressed questions related to the response of Antarctic ecosystems to human activity and climate change in the Scotia-Weddell seas, Antarctic Peninsula, Bellingshausen Sea, Ross Sea, and McMurdo Sound using a variety of ship-based, shore-based, and remote sensing technologies, such as satellites, acoustic and camera imaging systems, and remotely operated vehicles (ROVs). Contact Dr. Kendra Daly

Alastair Graham
Alastair Graham

Dr. Alastair Graham

Dr. Graham is a marine scientist, studying the link between ice sheets and the geological record. His research interests are focused on uncovering the histories, mechanisms, and drivers of past glacial and environmental change as recorded by high-latitude ocean floors and marine sedimentary records, as well as improving knowledge of the physical processes that govern the evolution of glacial and marine environments. Working from the glacier front to the deep sea, Dr Graham’s current research agenda is motivated by a set of questions steered towards the grand challenges faced by environmental and Antarctic science in the 21st century: how quickly, by how much, through what processes, and in response to what triggers do ice sheets and glaciers change over timescales not captured by observational records? An ongoing major objective of his work is to produce records of past ice‐sheet change at the poles that are significantly longer than satellite observations, providing the critical centennial to millennial context for changes to our warming planet and rising seas. Another key aspect is to study the processes of glacial environments using geophysical and geological tools to provide insight into modern and future ice-sheet behaviour. Dr Graham works routinely with glaciologists, oceanographers, and biologists to connect modern and palaeo processes in ice-sheet settings and increasingly looks to bridge ancient and contemporary systems in his research. Contact Dr. Alastair Graham

Brad E. Rosenheim
Brad Rosenheim

Dr. Brad Rosenheim

Dr. Rosenheim is a geochemist with interest in improving Antarctic sediment chronology and developing cold-water paleothermometers.  He has developed a pyrolysis separation method to more accurately date organic matter in sediments of the last deglaciation, enabling a regional approach to chronicling the last deglaciation.  Prior to the development of the Ramped PyrOx approach, cores were primarily dated using seldom present carbonates, in Antarctic margin sediments.  By developing a method that dates the organic matter in the sediment by separating old, contaminant organic matter, researchers can now make better use of cores that contain the glacial-deglacial sequence of sediment facies even if they do not contain calcium carbonate microfossils to date.  Dr. Rosenheim recently led an effort to retrieve sediments from Mercer Subglacial Lake, 1100 m beneath the Mercer Ice Stream draining both East and West Antarctica.  The expertise of his group is being used to constrain the carbon cycle and ice cover history of this unique environment. Contact Dr. Brad Rosenheim

Amelia Shevenell
Amelia Shevenell

Dr. Amelia Shevenell 

Ongoing interdisciplinary geochemical research in the Shevenell laboratory seeks to understand oceanic drivers of Antarctic ice dynamics on decadal to million year timescales, using marine sediment archives from both the deep Southern Ocean (ice-distal) and from Antarctica’s continental margins (ice-proximal). Our group employs inorganic and organic geochemical and micropaleontologic (foraminifera) paleoceanographic proxies for ocean temperature, ice volume, bottom water oxygen, and nutrients to determine both the evolution of the Southern Ocean system and to track the past influence of warm, nutrient-rich Circumpolar Deep Water on Antarctica’s marine terminating ice sheets during climatic warmings (e.g. the Miocene Climatic Optimum, the last deglaciation, and during the Holocene). Our work demonstrates a persistent link between Southern Ocean temperatures and Antarctic ice mass balance on geologic timescales. We are particularly interested in understanding the influence of the Southern Hemisphere Westerly Winds and tropical Pacific Ocean-Antarctic climate teleconnections on the rapid retreat of West and East Antarctic ice streams during the last deglaciation. Contact Dr. Amelia Shevenell

Nancy L. Williams
Nancy L. Williams

Dr. Nancy Williams

Dr. Williams studies the ocean’s role in the modern global carbon cycle with the ultimate goal of improving future projections of ocean carbon uptake. To accomplish this she makes ocean observations using a variety of tools ranging from discrete and underway water sampling methods to autonomous platforms equipped with biogeochemical sensors. Dr. Williams also analyzes publicly-available output from fully-coupled Earth System Models to understand how these new ocean observations can inform model development.  Dr. Williams’ past work has focused specifically on the Southern Ocean around Antarctica as part of the SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) project but the tools she uses can be employed to study any ocean region. She is also interested in ocean acidification, or how increasing ocean carbon dioxide content is changing ocean chemistry and affecting marine organisms, and data she collects can inform biological ocean acidification studies. The Southern Ocean is particularly susceptible to ocean acidification due to it’s naturally-high carbon dioxide content. Contact Dr. Nancy Williams

Courtesy Faculty

Xinfeng Liang
Xinfeng Liang

Dr. Xinfeng Liang

As a physical oceanographer, Dr. Liang is interested in using a combination of observations, numerical models and theory to understand how the ocean works and how the ocean is affected by and responds to the changing climate. In particular, Dr. Liang is interested in how the heat, salt, carbon and other biogeochemical tracers are transported in the global ocean. Another of Dr. Liang’s current research interests is the dynamic processes that can supply energy to ocean mixing, and these processes mainly include internal tides, near-inertial oscillations and mesoscale eddies. Dr. Liang has extensive seagoing experience, primarily in acquiring and processing data from Lowered/Vessel-mounted Acoustic Doppler Current Profiler (ADCP). Furthermore, he is familiar with the system of ocean state estimation (e.g. ECCO), which is powerful and has huge potential in addressing fundamental oceanographic questions. Contact Dr. Xinfeng Liang

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