Joshua C Koch, Ph.D.
Surface water / groundwater interactions; hyporheic zone hydrology and biogeochemistry; carbon, nitrogen, and phosphorus cycling; flow above / through frozen ground; preferential flow and soil pipe formation and transport.
Biography
Education
PhD 2010 University of Colorado, Boulder, CO Civil, Environmental, and Architectural Engineering
MS 2005 University of Arizona, Tucson, AZ Department of Hydrology
BA 2001 Wesleyan University, Middletown, CT Earth and Environmental Sciences
Professional Experience
2011 - Present Research Hydrologist, U.S. Geological Survey (USGS), Anchorage, AK
2006 - 2011 Student Hydrologist, Branch of Regional Research, USGS, Boulder, CO
2005 - 2006 Research Assistant, Institute of Alpine and Arctic Research, University of Colorado, Boulder
2003 - 2005 Research Assistant, Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, AZ
2002 - 2003 Hydrologist Intern, Branch of Regional Research, USGS, Lakewood, CO
2001 - 2002 Hydrologist Intern, MA-RI Water District, USGS, Northborough, MA
Professional Activities and/or Memberships
American Geophysical Union, Hydrology and Cryosphere Sections
American Water Resources Association - Alaska Chapter
Association of Polar Early Career Scientists
Science and Products
Beavers Impacting Tundra Ecosystems (BITE)
The range expansion of the North American beaver (Castor canadensis) has implications for water quality, aquatic ecosystems, and fisheries in Arctic streams.
Biogeochemistry of glaciers
Significant change to the Arctic and sub-arctic water cycle is underway, impacting hydrologic and biogeochemical fluxes. In southcentral Alaska, glacier mass loss, changes to precipitation (including the rain/snow fraction), thawing ground ice, and vegetation encroachment will change both magnitude and timing of water and solute fluxes downstream. Although altered fluxes of limiting...
Arctic Lake Food Webs
From 2011 to 2013 we investigated freshwater food webs of Arctic Coastal Plain lakes in Alaska to improve our understanding how Arctic freshwater food webs may respond to landscape change the warmer, drier future.
Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Permafrost thaw is leading to a myriad of changes in physical and chemical conditions throughout the Arctic.
Arctic – Boreal Catchment Studies
Catchment hydrology focuses on the movement of water and solutes from landscapes to waterbodies. Our research addresses questions such as: Where is the stream water coming from? How long did it take to get here? What solutes, nutrients, and/or contaminants did the water pick up along the way? Because streams and lakes gather water and solutes, we can learn about the entire watershed by...
Arctic Coastal Plain Studies
The Arctic Coastal Plain (ACP) is a large region of low-lying, lake-rich land on the North Slope of Alaska. This region is underlain by thick ground ice, which is susceptible to erosion and thaw. These physical changes are likely to alter ecosystems by changing the availability of habitats and food resources upon which wildlife depends. Our studies on the ACP aim to understand the link between...
Matanuska-Susitna Borough Wetland Modeling
This project aims to improve our understanding of the role of wetlands in controlling streamflow in southcentral Alaska using a groundwater – surface water flow model that can recreate the dynamic interactions between streams and wetlands.
Wolverine Glacier Ecosystem Studies
This project is an extension of the long-term Wolverine Glacier Benchmark Glacier project and is improving our understanding of solutes and nutrients in glacier basins, and how they fuel downstream ecosystems.
Arctic Boreal Vulnerability Experiment (ABoVE)
ABoVE: Vulnerability of inland waters and the aquatic carbon cycle to changing permafrost and climate across boreal northwestern North America.
Carbon released from thawing permafrost may fuel terrestrial and aquatic ecosystems or contribute to greenhouse gas emission, leading to a potential warming feedback and further thaw.
Nome Creek Experimental Watershed
The Nome Creek Experimental Watershed (NCEW) has been the site of multiple studies focused on understanding hydrology, biogeochemistry, and ecosystem changes related to permafrost thaw and fire in the boreal forest.
Hydro-Ecology of Arctic Thawing (HEAT): Hydrology
The Arctic is warming at higher rates than much of the rest of the world. For Alaska, this results in changes in hydrology and ecosystems – permafrost is thawing, changing landscapes and releasing nutrients to soils and streams.
Monitoring Thermokarst on the Landscapes of Northern Alaska
Permafrost – the thick layer of permanently frozen soil found in Arctic regions – has been thawing rapidly over the past century due to climate change. When permafrost thaws unevenly, it produces thermokarst landscapes, irregular surfaces of small hills interspersed with hollows. The processes that produce thermokarst can lead to significant changes within the surrounding ecosystems, altering...
Storm-scale and seasonal dynamics of carbon export from a nested subarctic watershed underlain by permafrost
Subarctic catchments underlain by permafrost sequester a major stock of frozen organic carbon (C), which may be mobilized as the Arctic warms. Warming can impact C export from thawing soils by altering the depth and timing of runoff related to changing storm and fire regimes and altered soil thaw depths. We investigated C export in a first order...
Koch, Joshua C.; Dornblaser, Mark; Striegl, Rob Arctic insect emergence timing and composition differs across thaw ponds of varying morphology
Freshwater ponds provide habitats for aquatic insects that emerge and subsidize consumers in terrestrial ecosystems. In the Arctic, insects provide an important seasonal source of energy to birds that breed and rear young on the tundra. The abundance and timing of insect emergence from arctic thaw ponds is poorly understood, but understanding...
Laske, Sarah M.; Gurney, Kirsty E. B.; Koch, Joshua C.; Schmutz, Joel A.; Wipfli, Mark S.
USGS permafrost research determines the risks of permafrost thaw to biologic and hydrologic resources
The U.S. Geological Survey (USGS), in collaboration with university, Federal, Tribal, and independent partners, conducts fundamental research on the distribution, vulnerability, and importance of permafrost in arctic and boreal ecosystems. Scientists, land managers, and policy makers use USGS data to help make decisions for development, wildlife...
Waldrop, Mark P.; Anderson, Lesleigh; Dornblaser, Mark; Erikson, Li H.; Gibbs, Ann E.; Herman-Mercer, Nicole M.; James, Stephanie R.; Jones, Miriam C.; Koch, Joshua C.; Leewis, Mary-Cathrine; Manies, Kristen L.; Minsley, Burke J.; Pastick, Neal J.; Patil, Vijay; Urban, Frank; Walvoord, Michelle A.; Wickland, Kimberly P.; Zimmerman, Christian Permafrost promotes shallow groundwater flow and warmer headwater streams
The presence of permafrost influences the flow paths of water through Arctic landscapes and thereby has the potential to impact stream discharge and thermal regimes. Observations from eleven headwater streams in Alaska showed that July water temperatures were higher in catchments with more near‐surface permafrost. We apply a fully coupled...
Sjoberg, Ylva; Janke, Adam K.; Painter, S; Coonradt, E.; Carey, Michael P.; O'Donnell, Jonathan A.; Koch, Joshua C. Carbon dioxide and methane flux in a dynamic Arctic tundra landscape: Decadal‐scale impacts of ice wedge degradation and stabilization
Ice wedge degradation is a widespread occurrence across the circumpolar Arctic causing extreme spatial heterogeneity in water distribution, vegetation, and energy balance across landscapes. These heterogeneities influence carbon dioxide (CO2) and methane (CH4) fluxes, yet there is little understanding of how they effect change in landscape‐level...
Wickland, Kimberly P.; Jorgenson, M.Torre; Koch, Joshua C.; Kanevskiy, Mikhail Z.; Striegl, Robert G. Fish growth rates and lake sulphate explain variation in mercury levels in ninespine stickleback (Pungitius pungitius) on the Arctic Coastal Plain of Alaska
Mercury concentrations in freshwater food webs are governed by complex biogeochemical and ecological interactions that spatially vary and are often mediated by climate. The Arctic Coastal Plain of Alaska (ACP) is a heterogeneous, lake-rich landscape where variability in mercury accumulation is poorly understood. Earlier research indicated that the...
Burke, Samantha M.; Zimmerman, Christian E.; Laske, Sarah M.; Koch, Joshua C.; Derry, Allison M.; Guernon, Stephanie; Branfireun, Brian A.; Swanson, Heidi K. Field-based method for assessing duration of infectivity for influenza A viruses in the environment
Understanding influenza A virus (IAV) persistence in wetlands is limited by a paucity of field studies relating to the maintenance of infectivity over time. The duration of IAV infectivity in water has been assessed under variable laboratory conditions, but results are difficult to translate to more complex field conditions. We tested a field-...
Reeves, Andrew B.; Ramey, Andrew M.; Koch, Joshua C.; Poulson, Rebecca L.; Stallknecht, David E. Permafrost hydrology drives the assimilation of old carbon by stream food webs in the Arctic
Permafrost thaw in the Arctic is mobilizing old carbon (C) from soils to aquatic ecosystems and the atmosphere. Little is known, however, about the assimilation of old C by aquatic food webs in Arctic watersheds. Here, we used C isotopes (δ13C, Δ14C) to quantify C assimilation by biota across 12 streams in arctic Alaska. Streams spanned watersheds...
O'Donnell, Jonathon A; Carey, Michael P.; Koch, Joshua C.; Xu, Xiaomei; Poulin, Brett; Walker, Jennifer; Zimmerman, Christian E. Soil physical, hydraulic, and thermal properties in interior Alaska, USA: Implications for hydrologic response to thawing permafrost conditions
Boreal forest regions are a focal point for investigations of coupled water and biogeochemical fluxes in response to wildfire disturbances, climate warming, and permafrost thaw. Soil hydraulic, physical, and thermal property measurements for mineral soils in permafrost regions are limited, despite substantial influences on cryohydrogeologic model...
Ebel, Brian A.; Koch, Joshua C.; Walvoord, Michelle A. Ice wedge degradation and stabilization impacts water budgets and nutrient cycling in Arctic trough ponds
Trough ponds are ubiquitous features of Arctic landscapes and an important component of freshwater aquatic ecosystems. Permafrost thaw causes ground subsidence, creating depressions that gather water, creating ponds. Permafrost thaw also releases solutes and nutrients, which may fertilize these newly formed ponds. We measured water budget elements...
Koch, Joshua C.; Jorgenson, M. Torre; Wickland, Kimberly P.; Kanevskiy, Mikhail Z.; Striegl, Robert G. Comparative nest survival of three sympatric loon species breeding in the Arctic
Identifying factors influencing nest survival among sympatric species is important for understanding and managing sources of variation in population dynamics of individual species. Three species of loons nest sympatrically in northern Alaska and differ in body size, life history characteristics, and population trends. We tested the effects of...
Uher-Koch, Brian D.; Koch, Joshua C.; Wright, Kenneth G.; Schmutz, Joel A. Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska
Permafrost (perennially frozen) soils store vast amounts of organic carbon (C) and nitrogen (N) that are vulnerable to mobilization as dissolved organic carbon (DOC) and dissolved organic and inorganic nitrogen (DON, DIN) upon thaw. Such releases will affect the biogeochemistry of permafrost regions, yet little is known about the chemical...
Wickland, Kimberly P.; Waldrop, Mark P.; Aiken, George R.; Koch, Joshua C.; Jorgenson, M. Torre; Striegl, Robert G.
Publication Finds That Permafrost Presence Results in Warmer Headwater Streams
Permafrost thaw is occurring across the Arctic with potential consequences for hydrology, ecosystems, humans, and wildlife. A team of scientists from the U.S. Geological Survey Alaska Science Center, the National Park Service, and the Department of Energy Oak Ridge National Laboratory are collaborating to understand the impacts of warming on the ecosystems in the Noatak Preserve in Alaska.