Current Postdoctoral Researchers

Angelee Pavanee Annasawmy

PhD, Oceanography, University of Montpellier (France) and University of Cape Town (South Africa), 2019. Dr. Annasawmy is working with Professor John Horne, Dr. Christian Reiss (NOAA Southwest Fisheries Science Center) and Dr. Gavin Macaulay on a project that aims to investigate the spatio-temporal variability in krill distribution and aggregation structures in the Bransfield Strait, Antarctica. The project is multi-faceted with ecological, scientific, fishery/management and technological perspectives and represents a comprehensive and collaborative effort to develop methodologies for long-term observations of ocean and coastal processes and marine ecosystems. The Antarctic krill, Euphausia superba, is a major component of the Southern Ocean’s ecosystem and is one of the main resources exploited by commercial fishing vessels in the area. The absence of updated high-resolution krill distribution data constitutes a major obstacle in determining the status of local krill stock and its response to fishing pressure and melting sea ice. New technologies are required for long-term observations of marine resources due to increasing costs of research at sea. This postdoctoral project therefore represents a first step in the validation of acoustic data acquired from new-generation echo sounders mounted on moorings that were deployed over a month at Nelson and Deception Islands. The main objectives are to develop an analysis method to compare the performance of the Kongsberg WBAT echo sounder vs. the Nortek Signature 100 profiler, and to investigate the aggregation structures and predator-prey interactions at Nelson and Deception Islands (two environmentally contrasting sites of the Southern Ocean).

Ellie Bors

PhD, Biological Oceanography, MIT-WHOI Joint Program, 2017. Dr. Bors is collaborating with Dr. Lorenz Hauser (UW School of Aquatic and Fisheries Science) and Dr. Ingrid Spies (NOAA Alaska Fisheries Science Center) on a project that aims to describe the population genetic consequences of climate-driven distributional shifts for fish in the Bering Sea. Focusing on Walleye pollock, which is the most valuable groundfish species in Alaska, Dr. Bors is using new genomic techniques to describe the spawning stock structure in the region, determine if genetic structure varies between warm and cool periods, and identify which fish stocks are moving into the Northern Bering Sea in response to recent anomalously warm temperatures. In addition to developing a rigorous molecular ecology research program, Dr. Bors has accrued substantial experience in marine policy as a 2017 Sea Grant Knauss Marine Policy Fellow and a 2018-2019 Fulbright Arctic Initiative Scholar. She hopes to engage in the dynamic interdisciplinary community at the UW and NOAA during her time as a JISAO postdoc.

headshot of CaseyCasey Clark

PhD, University of Alaska Fairbanks, 2019. Dr. Clark is working with Dr. Kristin Laidre to develop a method for estimating age at sexual maturity in Arctic mammals using concentrations of zinc and lead in teeth. The ability to estimate age at maturity is important for tracking changes in the status of wildlife populations, and this parameter is a key piece of information for many population models, which allow for projections of population status into the future. This information is currently difficult to obtain for many species, particularly those that live in remote and difficult to access locations such as the Arctic. The primary goal of this research is to generate a new tool for researchers and wildlife managers to more effectively monitor and manage populations of Arctic mammals, which represent critical subsistence resources for many northern communities and are key players in Arctic food webs.

Brian Green headshotBrian Green

PhD, Climate Science, Massachusetts Institute of Technology, 2018. With David Battisti, I am studying the interaction of regional tropical rainfall with the global tropical energy balance. Tropical rainfall provides water to billions of people, and connecting its regional distribution and dynamics to the global climate is one of the central challenges of climate science. The global tropical energy balance places strong constraints on the pattern and dynamics of tropical rainfall averaged across longitudes, explaining the location of the tropical rainfall maximum, for example, but has relatively little power to describe regional rainfall dynamics. Nonetheless, regional rainfall patterns are tied to their local energy and water vapor budgets; my research seeks to better understand how these regional patterns interact and are organized in response to larger-scale climate boundary conditions, such as the seasonal distribution of sunlight.

Colleen headshotColleen Hoffman

PhD, Earth Sciences, University of Minnesota, 2018. Dr. Hoffman is working with Dr. Randelle Bundy, UW School of Oceanography, and Dr. Jospeh Resing, JISAO-NOAA, to examine the mechanisms and kinetics of how diffuse flow hydrothermal iron in the Southern Pacific Ocean is stabilized and potentially upwelled in the Southern Ocean, fueling phytoplankton primary production. Phytoplankton are key players in the global carbon cycle but are often growth limited due to iron-poor surface waters. Hydrothermal vents could, therefore, be a previously unrecognized nutrient source to the surface ocean and play an important role in the global carbon cycle. Currently, two mechanisms, nanoparticles and organic complexation, are hypothesized to be responsible for basin-scale transport of hydrothermal iron. Dr. Hoffman will investigate iron-ligand (e.g. organics) relationships, ligand characterization, and kinetics of these reactions in hydrothermal plumes. The results from this research will advance our current understanding of how hydrothermal vents influence global geochemical cycles, and impact phytoplankton growth in the surface waters.

Sarah's headshotSara Sanchez

PhD, Oceanography (specialization Climate Science), Scripps Institution of Oceanography, 2018. Dr. Sanchez is interested in paleo-climate variability, tropical climate dynamics, and the development of geochemical archives to interpret past change in Earth’s climate system. Dr. Sanchez is working with Dr. Greg Hakim, UW Atmospheric Sciences, and Dr. Casey Saenger, JISAO, on a coral-based paleoclimate data assimilation project aiming to reconstruct climate variability in the tropical oceans. Climate models indicate that the tropics host some of the most robust responses to climate change, but monitoring low frequency change in the tropical oceans is difficult given the sparsity of observations prior to the satellite era. This work offers a new means of assessing of tropical climate variability; the results of this work will improve understanding of historical hydroclimate and surface temperature variations, the response of the tropics to forced change, and coral geochemistry- instrument calibration.

 

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