Turbulence, such as exemplified here in the Black Canyon of the Gunnison, can affect higher rates of gas exchange and in-stream gas concentrations close to atmospheric equilibrium.
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Continental-scale controls on greenhouse gas dynamics in rivers
(NSF Macrosystems 2021- ongoing) In 2021, Dr. Emily Bernhardt and I were funded to derive robust and continuous estimates of the greenhouse gases emitted to the atmosphere from the rivers of the United States, and to understand the drivers of emissions across rivers and over time. Along with a team of data scientists and postdocs (Spencer Rhea, Mike Vlah, Dr. Alice Carter), we are linking these greenhouse gas fluxes with concurrent estimates of stream metabolism, rates of groundwater inflow, and gas exchange between the stream and atmosphere to distinguish between instream and catchment derived contributions to riverine gas fluxes.
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Geological and biological methane and ancient carbon subsidies to freshwater food webs
(NSF EAGER 2018-2022, NSF DOB 2017-2022, dissertation 2012-2016) Most ecosystems rely on photosynthetically-fixed carbon as a basal energy source. However, in the groundwater underneath gravel-bed river floodplains, large stoneflies (river insects) can survive largely using carbon fixed via methanogenesis and methanotrophy, or the microbial production and consumption of methane, representing an extremely unique food web. Even more unique, some of these systems might incorporate ancient carbon (some in the form of methane) from springs and from shale, leading living organismal biomass to have carbon ages ranging from 7-16 thousand years before present! After documenting this unique possibility in Montana and Washington during my dissertation, we have been investigating shale and warm spring (from earth's crust or mantle) contributions of ancient carbon and methane to biomass in Colorado, funded by a NSF EAGER grant awarded in 2018.
We are investigating not only energy sources to these subsurface invertebrate communities, but the adaptations that facilitate survival and reliance on unconventional energy sources. We are also investigating the genomic underpinnings of these adaptations using reference genomes and population genetics approaches. We have found that stoneflies can tolerate up to days of anoxia, and recover to full mobility! This would allow them to access microbial biofilms that thrive at anoxic-oxic interfaces, such as those associated with methane cycling.
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Warm springs are indicated by the massive travertine deposit (right, carbonate formation) on the Cement Creek Ranch. We were able to access and use this site thanks to the generosity of Chris and David Baxter, owners and stewards of this beautiful floodplain.
Jess Forbes, our amazing team member from Crested
Butte, CO, and Dr. Jack Stanford collect invertebrates via kicknetting in Cement Creek.
The first Paraperla frontalis we found in Colorado! After 2 years of well installations and sampling!
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Steven Gougherty prepares to collect respiration chamber measurements of CO2 flux from the collars installed along drying kettle pond perimeters.
Susan Campbell, REU student from Allegheny College '17, prepares to collect samples for headspace equilibrations.
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Greenhouse gas flux from exposed sediments of high-elevation ponds
(2016-2019) High-elevation systems are reacting rapidly to climate change, with shorter winters, lower duration of snow cover and extent of snow pack, and warmer summers. This rapid response makes high elevation systems a sentinel of change, and an optimal place to measure ecological responses. Graduate student Steven Gougherty, REU student Susan Campbell, and I studied the effects of varying pond hydroperiods (duration of pond having surface water present each year) and sediment extractable nutrient concentrations on greenhouse gas dynamics in pond waters and sediments.
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Ecology and hydrology of non-perennial river systems
(Dry Rivers RCN 2019- ongoing, other)
The majority of the world's rivers lose flow and sometimes have a dry surface channel over the course of a typical year. The Dry Rivers Research Collaborative Network brings together scientists from across the world to investigate how the structure and function of these systems, both above and below ground, vary over the course of the hydrograph. We additionally consider how we might better measure, consider, and manage these systems.
(Dry Rivers RCN 2019- ongoing, other)
The majority of the world's rivers lose flow and sometimes have a dry surface channel over the course of a typical year. The Dry Rivers Research Collaborative Network brings together scientists from across the world to investigate how the structure and function of these systems, both above and below ground, vary over the course of the hydrograph. We additionally consider how we might better measure, consider, and manage these systems.
- DelVecchia,Amanda G., Daniel C. Allen, Thibault Datry, Margaret Shanafield, Ken Fritz, Stephanie Kampf, Michelle H. Busch, Kendra Kaiser, Corey A. Krabbenhoft, Ryan M. Burrows, Rachel Stubbington, Samuel C. Zipper, Michael T. Bogan, Kate S. Boersma, Katie Costigan, Margaret Zimmer, Adam S. Ward (2022) ‘Reconceptualizing the hyporheic zone of non-perennial streams’. Freshwater Science.
- Krabbenhoft, Corey A., George H. Allen, Peirong Lin, Sarah E. Godsey, Daniel C. Allen, Ryan M. Burrows, Amanda G. DelVecchia, Ken M. Fritz, Margaret Shanafield, Amy J. Burgin, Margaret Zimmer, Thibault Datry, Walter K. Dodds, C. Nathan Jones, Meryl C. Mims, Catherin Franklin, John C. Hammond, Samuel C. Zipper, Adam S. Ward, Katie H. Costigan, Hylke E. Beck, and Julian D. Olden (2022) ‘Assessing placement bias of the global river gauge network’. Nature Sustainability.
- Compson, Zacchaeus G., Shang Gao, Yanh Hong, Romain Sarremejane, Benjamine J. Ruddell, Amanda G. DelVecchia, Ryan M. Burrows, Wendy A. Monk, Daniel C. Allen. ‘Dryland Rivers’. Book chapter. Encyclopedia of Inland Waters. In review.
- Zimmer, Margaret, Kendra Kaiser, Katie H. Costigan, George H. Allen, Joanna Blaszczak, Kate S. Boersma, Michael T. Bogan, Ryan M. Burrows, Michelle H. Busch, Thibault Datry, Amanda G. DelVecchia, Walter Dodds, Ken M. Fritz, Sarah Godsey, Rebecca Hale, John Hammond, Jacob Hosen, Nathan C. Jones, Stephanie Kampf, Corey A. Krabbenhoft, Meryl C. Mims, Julian D. Olden, Albert Ruhi, Maragaret Shanafield, Adam Ward, Samuel C. Zipper, Daniel C. Allen (2020) ‘Zero or not? Causes and consequences of zero-flow stream gage readings’. Wiley Interdisciplinary Review: Water. DOI:10.1002/wat2.1436
