Scientists & Staff

Speaking to visitors at the Marcell Experimental Forest

Stephen Sebestyen

Research Hydrologist
1831 Hwy 169 East
Grand Rapids, MN, 55744-3399
Phone: 218-326-7108

Contact Stephen Sebestyen

Resume (191 KB PDF)

Current Research

My scientific interests focus on determining how hydrological and biogeochemical processes interact in ecosystems. I study how source variation and landscape processes affect the flow of water and solutes through the environment.

I am a research hydrologist with the USDA Forest Service in Grand Rapids, MN. I devote portions of my time to research at the Marcell Experimental Forest (MEF) and national-scale syntheses of data from catchment studies on Experimental Forests and Ranges of the USDA Forest Service. At the MEF, I co-lead research planning and research on hydrological and biogeochemical research. I have developed a research program that builds upon the 50-year legacy of research at this site. The MEF was established to study the ecology and hydrology of peatlands and uplands along the southern fringe of the boreal zone. I pursue research related to the effects of nitrogen pollution on ecosystem functions, carbon cycling in peatlands, understanding effects of climate variability, interactions of dissolved organic matter with mercury and other trace metals, and quantifying effects of landscape disturbance on water and solutes yields. I am an investigator in the SPRUCE Experiment (Spruce and Peatland Response Under Climatic and Environmental change), a large-scale, experiment in which above- and below-ground temperatures are being manipulated in a black spruce-Sphagnum bog at the MEF.

I participate and co-lead data synthesis efforts on catchment studies to investigate ecosystem responses to climate change, atmospheric deposition, disturbance, and forest management practices. The intent of these studies is to broaden understanding to national and global scales.

At the Sleepers River Research Watershed in northeastern Vermont, I explore how sources of stream nitrate and dissolved organic matter (DOM) vary among events, seasons, and years. My research elsewhere in the northeastern USA includes studies of nitrate sources, and DOM dynamics.

I study how groundwater seepage influences biogeochemical cycles in lakes and wetlands. With past work, I have explored the effects of lakeshore seepage on pore water biogeochemistry and biological communities in lakes of the Adirondack Mountains of New York. In several new studies, I collaborate on research to quantify effects of groundwater seepage on lake trophic status.

I collaborate with a broad range of research scientists, graduate students, and undergraduate students. My position as a Forest Service scientist and being adjunct faculty at the University of Minnesota and Michigan Tech allow me to be highly involved with graduate and postdoctoral researchers.

Research Interests

With future projects and collaborations, I will pursue research that:

  • Quantifies rates of terrestrial and aquatic biogeochemical transformations to definitively pinpoint the landscape processes that affect water chemistry.
  • Determines how sources, transformations, and transport processes interact to control nutrient availability within ecosystems.
  • Quantifies how short-term processes that occur at discrete locations and times (the hotspots and hot moments of biogeochemical processes) are important when considered at the ecosystem level.
  • Considers how to scale up understanding of hydrological and biogeochemical processes from plot level studies and point monitoring locations to larger landscape units.
  • Establishes monitoring and experimental (manipulative) studies to identify how the timing, release, and cycling of solutes in catchments is affected by climatic and land use / land cover changes.

Why This Research is Important

  1. The flow of water transfers energy and matter from the atmosphere and terrestrial landscapes to lakes, streams, wetlands, and coastal zones. My scientific interests center on understanding how water and reactive chemicals are transported and transformed in the environment. With an emphasis on catchment science, I study hydrological and biogeochemical cycles to identify ways to effectively maintain water quality and ecosystem productivity. I use multiple approaches (hydrologic, biologic, geochemical, biogeochemical, and isotopic) across range of temporal, spatial, climatic, and ecological settings to study such issues as atmospheric pollutant deposition, forest health, ecosystem acidification, nutrient enrichment of surface waters, and ecosystem response to climate change.
  2. The variation of stream nutrient concentrations over event and seasonal time scales reflects complex biogeochemical and hydrological processes that affect ecosystem functions, but more fundamentally, relates to the availability of biologically-essential substances that fuel life cycles in catchments, headwater streams, and downstream water bodies.
  3. In landscapes where human activities enrich nutrient availability and affect land use / land cover, my work highlights the need to consider multiple elements and interactions of water and nutrient cycles in the context of coupled hydrological and biogeochemical cycles that control surface water chemistry. For example, I study how the nutrient enrichment of ecosystems by human activities directly affects the forms and concentrations of nitrogen in streams. Understanding the linkages between atmospheric sources of nitrogen to forests and streams helps to inform scientists, land managers, and legislators who seek to protect the valuable natural resources provided by forests.

Professional Organizations

  • American Association for the Advancement of Science
  • American Geophysical Union
  • International Association of Hydrological Sciences

Awards & Recognition

  • Northern Research Station Director's Early Career Scientist Award, 2013 In recognition of exemplary contributions to the fields of biogeochemistry and hydrology across the US, and locally at the Marcell Experimental Forest. Your research on nitrogen and dissolved organic matter identifying sources, chemical transformations,
  • Forest Service award for contributions to a strategic focus document on the Clean Air, 2008 Forest Service award for contributions to a strategic focus document on the Clean Air

Featured Publications & Products

Publications & Products

Research Datasets

  • Verry, Elon S.; Elling, Arthur E.; Sebestyen, Stephen D.; Kolka, Randall K.; Kyllander, Richard. 2018. Marcell Experimental Forest peatland and upland water table elevations. Fort Collins, CO: Forest Service Research Data Archive.

National Research Highlights

Phenocam and Antenna on top of the pierce laboratory at the Hubbard Brook Experimental Forest, NH. USDA Forest Service

“Smart Forests” Digital Environmental Sensors and Telecommunications Take Research to New Levels

Year: 2015

Scientific breakthroughs of the 21st century will be powered by tools that help researchers collect and manipulate massive datasets, visualize that data, and offer new ways of understanding the scientific processes behind that information. Forest Service scientists are taking a lead in developing a national Experimental Forests and Ranges “Smart Forests” Network. This network of wired forests uses digital environmental sensors, wireless communications, and new data visualization programs to create a powerful integrated research and monitoring program for the nation’s air, water, forest and rangeland resources.

Last modified: Thursday, September 29, 2016