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.
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
Education and Certifications
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
Affiliations and Memberships*
American Geophysical Union, Hydrology and Cryosphere Sections
American Water Resources Association - Alaska Chapter
Association of Polar Early Career Scientists
Science and Products
Forecasting wildlife response to rapid warming in the Alaskan Arctic
Life in the main channel: long-term hydrologic control of microbial mat abundance in McMurdo Dry Valley streams, Antarctica
Morphology-dependent water budgets and nutrient fluxes in arctic thaw ponds
Pronounced chemical response of Subarctic lakes to climate-driven losses in surface area
Runoff sources and flowpaths in a partially burned, upland boreal catchment underlain by permafrost
Effects of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence
Thermokarst and thaw-related landscape dynamics -- an annotated bibliography with an emphasis on potential effects on habitat and wildlife
Hydrologic controls on the transport and cycling of carbon and nitrogen in a boreal catchment underlain by continuous permafrost
Review: groundwater in Alaska (USA)
Rapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA)
Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes
Changing Arctic ecosystems - measuring and forecasting the response of Alaska's terrestrial ecosystem to a warming climate
Science and Products
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Forecasting wildlife response to rapid warming in the Alaskan Arctic
Arctic wildlife species face a dynamic and increasingly novel environment because of climate warming and the associated increase in human activity. Both marine and terrestrial environments are undergoing rapid environmental shifts, including loss of sea ice, permafrost degradation, and altered biogeochemical fluxes. Forecasting wildlife responses to climate change can facilitate proactive decisionAuthorsCaroline R. Van Hemert, Paul L. Flint, Mark S. Udevitz, Joshua C. Koch, Todd C. Atwood, Karen L. Oakley, John M. PearceLife in the main channel: long-term hydrologic control of microbial mat abundance in McMurdo Dry Valley streams, Antarctica
Given alterations in global hydrologic regime, we examine the role of hydrology in regulating stream microbial mat abundance in the McMurdo Dry Valleys, Antarctica. Here, perennial mats persist as a desiccated crust until revived by summer streamflow, which varies inter-annually, and has increased since the 1990s. We predicted high flows to scour mats, and intra-seasonal drying to slow growth. ResAuthorsTyler J. Kohler, Lee F. Stanish, Steven W. Crisp, Joshua C. Koch, Daniel Liptzin, Jenny L. Baeseman, Diane M. McKnightMorphology-dependent water budgets and nutrient fluxes in arctic thaw ponds
Thaw ponds on the Arctic Coastal Plain of Alaska are productive ecosystems, providing habitat and food resources for many fish and bird species. Permafrost in this region creates unique pond morphologies: deep troughs, shallow low-centred polygons (LCPs) and larger coalescent ponds. By monitoring seasonal trends in pond volume and chemistry, we evaluated whether pond morphology and size affect watAuthorsJoshua C. Koch, Kirsty Gurney, Mark S. WipfliPronounced chemical response of Subarctic lakes to climate-driven losses in surface area
Losses in lake area have been observed for several Arctic and Subarctic regions in recent decades, with unknown consequences for lake ecosystems. These reductions are primarily attributed to two climate-sensitive mechanisms, both of which may also cause changes in water chemistry: (i) increased imbalance of evaporation relative to inflow, whereby increased evaporation and decreased inflow act to cAuthorsTyler L. Lewis, Mark S. Lindberg, Joel A. Schmutz, Patricia J. Heglund, Jennifer R. Rover, Joshua C. Koch, Mark R. BertramRunoff sources and flowpaths in a partially burned, upland boreal catchment underlain by permafrost
Boreal soils in permafrost regions contain vast quantities of frozen organic material that is released to terrestrial and aquatic environments via subsurface flowpaths as permafrost thaws. Longer flowpaths may allow chemical reduction of solutes, nutrients, and contaminants, with implications for greenhouse gas emissions and aqueous export. Predicting boreal catchment runoff is complicated by soilAuthorsJoshua C. Koch, Colin P. Kikuchi, Kimberly P. Wickland, Paul SchusterEffects of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence
Permafrost soils store over half of global soil carbon (C), and northern frozen peatlands store about 10% of global permafrost C. With thaw, inundation of high latitude lowland peatlands typically increases the surface-atmosphere flux of methane (CH4), a potent greenhouse gas. To examine the effects of lowland permafrost thaw over millennial timescales, we measured carbon dioxide (CO2) and CH4 excAuthorsCarmel E. Johnston, Stephanie A. Ewing, Jennifer W. Harden, Ruth K. Varner, Kimberly P. Wickland, Joshua C. Koch, Christopher C. Fuller, Kristen L. Manies, M. Torre JorgensonThermokarst and thaw-related landscape dynamics -- an annotated bibliography with an emphasis on potential effects on habitat and wildlife
Permafrost has warmed throughout much of the Northern Hemisphere since the 1980s, with colder permafrost sites warming more rapidly (Romanovsky and others, 2010; Smith and others, 2010). Warming of the near-surface permafrost may lead to widespread terrain instability in ice-rich permafrost in the Arctic and the Subarctic, and may result in thermokarst development and other thaw-related landscapeAuthorsBenjamin M. Jones, Courtney L. Amundson, Joshua C. Koch, Guido GrosseHydrologic controls on the transport and cycling of carbon and nitrogen in a boreal catchment underlain by continuous permafrost
Boreal ecosystems represent a large carbon (C) reservoir and a substantial source of greenhouse gases. Hydrologic conditions dictate whether C leached from boreal soils is processed in catchments or flushed to less productive environments via the stream. This study quantified hydrologic and biogeochemical C loss from a boreal catchment underlain by frozen silt, where flowpaths may deepen as the acAuthorsJoshua C. Koch, Robert L. Runkel, Robert G. Striegl, Diane M. McKnightReview: groundwater in Alaska (USA)
Groundwater in the US state of Alaska is critical to both humans and ecosystems. Interactions among physiography, ecology, geology, and current and past climate have largely determined the location and properties of aquifers as well as the timing and magnitude of fluxes to, from, and within the groundwater system. The climate ranges from maritime in the southern portion of the state to continentalAuthorsJ.B. Callegary, C.P. Kikuchi, Joshua C. Koch, M. R. Lilly, S. A. LeakeRapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA)
In high-latitude catchments where permafrost is present, runoff dynamics are complicated by seasonal active-layer thaw, which may cause a change in the dominant flowpaths as water increasingly contacts mineral soils of low hydraulic conductivity. A 2-year study, conducted in an upland catchment in Alaska (USA) underlain by frozen, well-sorted eolian silt, examined changes in infiltration and runofAuthorsJoshua C. Koch, Stephanie A. Ewing, Robert G. Striegl, Diane M. McKnightReorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes
The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic caAuthorsM. Torre Jorgenson, Jennifer Harden, Mikhail Kanevskiy, Jonathan O'Donnell, Kim Wickland, Stephanie Ewing, Kristen Manies, Qianlai Zhuang, Yuri Shur, Robert G. Striegl, Joshua C. KochChanging Arctic ecosystems - measuring and forecasting the response of Alaska's terrestrial ecosystem to a warming climate
The Arctic Coastal Plain of northern Alaska is a complex landscape of lakes, streams, and wetlands scattered across low relief tundra that is underlain by permafrost. This region of the Arctic has experienced a warming trend over the past three decades, leading to thawing of on-shore permafrost and the disappearance of sea ice at an unprecedented rate. The loss of sea ice has increased ocean waveAuthorsJohn M. Pearce, Anthony R. DeGange, Paul L. Flint, Tom F. Fondell, David D. Gustine, Leslie E. Holland-Bartels, Andrew G. Hope, Jerry W. Hupp, Joshua C. Koch, Joel A. Schmutz, Sandra L. Talbot, David H. Ward, Mary E. Whalen - Web Tools
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government