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
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.
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.
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...
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. Nutrient 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...
Koch, Joshua C.; Fondell, Tom F.; Schmutz, Joel A.; Laske, Sarah M. Patterns 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...
Burke, Samantha M.; Zimmerman, Christian E.; Branfireun, Brian A.; Koch, Joshua C.; Swanson, Heidi K. Tracer-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,...
Koch, Joshua C.; Toohey, Ryan C.; Reeves, D.M. Potential effects of permafrost thaw on arctic river ecosystems
No abstract available.
O'Donnell, Jonathan A.; Zimmerman, Christian E.; Carey, Michael P.; Koch, Joshua C. Multidecadal 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...
Toohey, Ryan C.; Herman-Mercer, Nicole M.; Schuster, Paul F.; Mutter, Edda A.; Koch, Joshua C. Lateral 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...
Koch, Joshua C. Landscape 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...
Brown, Dana R. N.; Jorgenson, M. Torre; Kielland, Knut; Verbyla, David L.; Prakash, Anupma; Koch, Joshua C. Surface 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...
Laske, Sarah M.; Haynes, Trevor B.; Rosenberger, Amanda E.; Koch, Joshua C.; Wipfli, Mark S.; Whitman, Matthew; Zimmerman, Christian E.