Current Lab Team
Gordon Holtgrieve – PI
I have wide-ranging interests, including how animals control ecosystem functioning, terrestrial-aquatic linkages, global biogeochemical cycles, fisheries conservation, and links between food and freshwater. My research uses a combination of field-based empirical science and statistical modeling of data to better understand how ecosystems function. A large component of my research involves using geochemical tracers to gain insight into how nutrients and energy flow at local to global scales. See my Google Scholar profile and my UW College of the Environment page.
Thomas Pool – Post Doc
Freshwater, estuarine, and marine systems contain an amazing diversity of flora and fauna that is often hidden from our view. I am a aquatic community ecologist who studies food web interactions within those systems. My research interests include studying the impacts of dams, invasion ecology, biogeography and conservation biology. To explore these topics, I use a combination of empirical experiments, field surveys, and spatial modeling methods. I am also interested in exploring alternative teaching approaches to communicate science at the university level. Please look at my ResearchGate page to see my most recent work.
Elizabeth (Liz) Elmstrom – M.S. Student
My major research interest focuses on the cycling of elements through the environment, specifically the biogeochemistry of carbon and nitrogen in aquatic ecosystems. My previous work has focused on the impacts of watershed deforestation, urbanization and large scale global change on carbon and nitrogen dynamics in New England stream and estuaries and in mangrove-estuary systems of Trinidad and Panama. My current work focuses impacts of altered hydroclimatic conditions in Puget Sound rivers on nitrogen cycling in the context of climate change. More specifically, I am interested in using stable isotopes as tools to identify nitrogen sources and understand riverine nitrogen dynamics from headwaters out to sea.
Megan Feddern – M.S. Student
I am interested in understanding how these changes alter ecosystem structure with regards to prey and nutrient availability. My previous work looked at mitigation of disease in endangered fauna and population monitoring of commercially important species. My current work assesses how climatic regime shifts and prey availability are related to trophic position of top predators in Puget Sound and coastal Washington. While my current research primarily consists of compound specific stable isotope analyses, I am also interested in using compartment models and integrative assessments to improve applications of stable isotope data to ecosystem based management strategies.
Lilian (Lily) McGill – M.S. Student
Broadly, I’m interested in using quantitative methods to promote conservation of freshwater systems. My current research focuses on assessing climate risk to stream flows in Puget Sound rivers. In collaboration with Ashely E. Steel (USDA Forest Service), I am utilizing network models of water isotopes and air-water correlations to produce fine-scale spatial estimates of current and future water sources across the Snoqualmie River basin.
Ben Miller – Ph.D. Student
My research seeks to identify the sources and fates of carbon in lake, river, and stream ecosystems. Previously, this has included studying terrestrial-aquatic linkages in arctic streams, spatial variations in carbon gas fluxes throughout hydropower complexes on the Snake and Columbia Rivers, and temporal variations in carbon gas fluxes in the Three Gorges Reservoir. I am continuing my study of how hydropower alters riverine carbon biogeochemistry with the USGS and NOAA following dam removal on Washington’s Elwha River. I am particularly interested in how dynamic physical and chemical conditions in aquatic ecosystems enable different pathways for microbial oxidation of carbon. My primary research interest is determining the importance of methane production and oxidation to the food web in Tonle Sap Lake, Cambodia.
Rebekah (Beka) Stiling – M.S. Student
My research project is in the early stages of development focusing on the ecology of high-elevation lakes and exploring the role that stocked trout play in lake ecosystems. Broadly, my interests are in the freshwater realm and exploring watershed function; I am particularly interested in the intersection of physical processes and biological communities. Historically I have focused more on river hydrology and community ecology. Here in the Holtgrieve Lab I am excited about growing my skills and knowledge to include the use of biogeochemical tracers to understand the flow of nutrients and energy through ecological communities. I am co-advised by Julian Olden.
Hyejoo Ro – SAFS undergraduate
I am an undergraduate student in SAFS. I joined the Holtgrieve lab with interests in food web dynamics and the use of stable isotopes to help determine these kinds of interactions. The current project I am working on looks into the fatty acid signatures of microbial communities in soil. Identifying major groups of microbe communities will give insight to how nitrogen is getting used and converted through the ecosystem. This study will hopefully supplement a broader scale study looking into marine derived nutrients to freshwater and terrestrial systems.
Nick Ulacia – SAFS undergraduate
I am interested in food web ecology of freshwaters. Through the collection of water samples and trout specimens from alpine lakes throughout the Pacific Northwest, I am creating a primary assessment of food chain length in these understudied lakes using amino acid stable isotope analysis. I hope to determine whether or not there is a significant difference between fish populations on the West and East slopes of the Cascade mountain range. In addition, we plan to test for the effects of industrial pollution in these “pristine” lake systems.
As our first lab member Sydney will always be HEEL royalty. During her time at UW she worked on everything from salmon ecology in Alaska to nitrate isotopes in Puget Sound rivers. She also plays a mean uke. Sydney is now pursuing a Ph.D. at Brown University with Meredith Hastings.
Jordan Lee – B.S. 2015
I graduated from SAFS in 2015. For my capstone project I studied lipid metabolism in Alaskan sockeye salmon. Generally speaking, my research examined how partitioning of fatty acid energy reserves translates to overall survival and reproductive success. I used fatty acid composition data to characterize changes in sockeye salmon lipids as they migrate to natal streams for reproduction.
Rachel is an undergraduate student majoring in Biology and minoring in Spanish. For almost two years she was a lab assistant in the Holtgrieve Lab and widely known as “The Rock” (resemblance is obvious). In 2014, she helped with field research in Olympic National Park and worked on a project using stable nitrogen isotopes from Cambodia fishes. While interested in conservation ecology in the Pacific Northwest, she has decided to focus her research on physiology.
Mike Vlah – M.Sc. 2017
I am interested in the ways in which nutrients and energy move through food webs, including those that are not obviously connected. My work seeks to quantify linkages that are known, identify those that are unknown, and determine the environmental conditions that govern food web dynamics. I use primarily elemental and compound-specific isotope analyses in my experimental approaches, but I believe a solid foundational knowledge of natural history is essential to good ecological work, and I strive continually to build my own. Spirit animal: Black lab