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
Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska
Comparative nest survival of three sympatric loon species breeding in the Arctic
Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska
Nutrient dynamics in partially drained arctic thaw lakes
Patterns and controls of mercury accumulation in sediments from three thermokarst lakes on the Arctic Coastal Plain of Alaska
Tracer-based evidence of heterogeneity in subsurface flow and storage within a boreal hillslope
Potential effects of permafrost thaw on arctic river ecosystems
Multidecadal increases in the Yukon River Basin of chemical fluxes as indicators of changing flowpaths, groundwater, and permafrost
Lateral and subsurface flows impact arctic coastal plain lake water budgets
Landscape effects of wildfire on permafrost distribution in interior Alaska derived from remote sensing
Surface water connectivity drives richness and composition of Arctic lake fish assemblages
Role of ground ice dynamics and ecological feedbacks in recent ice wedge degradation and stabilization
Potential for real‐time understanding of coupled hydrologic and biogeochemical processes in stream ecosystems: Future integration of telemetered data with process models for glacial meltwater streams
Science and Products
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Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska
Permafrost (perennially frozen) and active-layer (seasonally thawed) soils varying in soil carbon (C) and nitrogen (N) content and radiocarbon age were collected from three sites in interior Alaska to determine potential release of dissolved organic carbon (DOC), total dissolved N (TDN), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (DIN) upon thaw. Soil cores were cut into 15 - Multimedia
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- Publications
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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 competition, nest site selection, and water level variaAuthorsBrian D. Uher-Koch, Joshua C. Koch, Kenneth G. Wright, Joel A. SchmutzDissolved 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 composition and source variability of active-layer (seasonaAuthorsKimberly P. Wickland, Mark P. Waldrop, George R. Aiken, Joshua C. Koch, M. Torre Jorgenson, Robert G. StrieglNutrient dynamics in partially drained arctic thaw lakes
Thaw lakes are ubiquitous on arctic coastal plains (ACPs). While many thaw lakes have steep banks, stable water levels, and static surface areas, others only partially fill their basins and vary in area over the summer. These partially drained lakes (PDLs) are hydrologically connected to the wetlands immediately surrounding them. Heat and nutrient availability limit aquatic productivity on ACPs, aAuthorsJoshua C. Koch, Tom F. Fondell, Joel A. Schmutz, Sarah M. LaskePatterns and controls of mercury accumulation in sediments from three thermokarst lakes on the Arctic Coastal Plain of Alaska
The biogeochemical cycle of mercury will be influenced by climate change, particularly at higher latitudes. Investigations of historical mercury accumulation in lake sediments inform future predictions as to how climate change might affect mercury biogeochemistry; however, in regions with a paucity of data, such as the thermokarst-rich Arctic Coastal Plain of Alaska (ACP), the trajectory of mercurAuthorsSamantha M. Burke, Christian E. Zimmerman, Brian A. Branfireun, Joshua C. Koch, Heidi K. SwansonTracer-based evidence of heterogeneity in subsurface flow and storage within a boreal hillslope
Runoff from boreal hillslopes is often affected by distinct soil boundaries, including the frozen boundary and the organic – mineral boundary (OMB), where highly porous and hydraulically-conductive organic material overlies fine-grained mineral soils. Viewed from the surface, ground cover appears as a patchwork on sub-meter scales, with thick, moss mats interspersed with lichen-covered, silty soilAuthorsJoshua C. Koch, Ryan C. Toohey, D.M. ReevesPotential effects of permafrost thaw on arctic river ecosystems
No abstract available.AuthorsJonathan A. O'Donnell, Christian E. Zimmerman, Michael P. Carey, Joshua C. KochMultidecadal increases in the Yukon River Basin of chemical fluxes as indicators of changing flowpaths, groundwater, and permafrost
The Yukon River Basin, underlain by discontinuous permafrost, has experienced a warming climate over the last century that has altered air temperature, precipitation, and permafrost. We investigated a water chemistry database from 1982 to 2014 for the Yukon River and its major tributary, the Tanana River. Significant increases of Ca, Mg, and Na annual flux were found in both rivers. Additionally,AuthorsRyan C. Toohey, Nicole M. Herman-Mercer, Paul F. Schuster, Edda A. Mutter, Joshua C. KochLateral and subsurface flows impact arctic coastal plain lake water budgets
Arctic thaw lakes are an important source of water for aquatic ecosystems, wildlife, and humans. Many recent studies have observed changes in Arctic surface waters related to climate warming and permafrost thaw; however, explaining the trends and predicting future responses to warming is difficult without a stronger fundamental understanding of Arctic lake water budgets. By measuring and simulatinAuthorsJoshua C. KochLandscape effects of wildfire on permafrost distribution in interior Alaska derived from remote sensing
Climate change coupled with an intensifying wildfire regime is becoming an important driver of permafrost loss and ecosystem change in the northern boreal forest. There is a growing need to understand the effects of fire on the spatial distribution of permafrost and its associated ecological consequences. We focus on the effects of fire a decade after disturbance in a rocky upland landscape in theAuthorsDana R. N. Brown, M. Torre Jorgenson, Knut Kielland, David L. Verbyla, Anupma Prakash, Joshua C. KochSurface water connectivity drives richness and composition of Arctic lake fish assemblages
Surface water connectivity can influence the richness and composition of fish assemblages, particularly in harsh environments where colonisation factors and access to seasonal refugia are required for species persistence. Studies regarding influence of connectivity on Arctic fish distributions are limited and are rarely applied to whole assemblage patterns. To increase our understanding of how suAuthorsSarah M. Laske, Trevor B. Haynes, Amanda E. Rosenberger, Joshua C. Koch, Mark S. Wipfli, Matthew Whitman, Christian E. ZimmermanRole of ground ice dynamics and ecological feedbacks in recent ice wedge degradation and stabilization
Ground ice is abundant in the upper permafrost throughout the Arctic and fundamentally affects terrain responses to climate warming. Ice wedges, which form near the surface and are the dominant type of massive ice in the Arctic, are particularly vulnerable to warming. Yet processes controlling ice wedge degradation and stabilization are poorly understood. Here we quantified ice wedge volume and deAuthorsMark Torre Jorgenson, Mikhail Kanevskiy, Yuri Shur, Natalia Moskalenko, Dana Brown, Kimberly P. Wickland, Robert G. Striegl, Joshua C. KochPotential for real‐time understanding of coupled hydrologic and biogeochemical processes in stream ecosystems: Future integration of telemetered data with process models for glacial meltwater streams
While continuous monitoring of streamflow and temperature has been common for some time, there is great potential to expand continuous monitoring to include water quality parameters such as nutrients, turbidity, oxygen, and dissolved organic material. In many systems, distinguishing between watershed and stream ecosystem controls can be challenging. The usefulness of such monitoring can be enhanceAuthorsDiane M. McKnight, Karen D. Cozzetto, James D. S. Cullis, Michael N. Gooseff, Christopher Jaros, Joshua C. Koch, W. Berry Lyons, Roseanna M. Neupauer, Adam N. Wlostowski - 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