|
Continental-scale controls on greenhouse gas dynamics in rivers
(NSF Macrosystems 2021- ongoing) PIs: Dr. DelVecchia & Dr. Emily Bernhardt In 2021, we 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 (Dr. Nick Marzolf, Dr. Heili Lowman, Dr. Yuseung Shin, 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.
When we analyze NEON data, we compare point measurements that were collected in stream runs. Many variables across studies are collected in stream runs, but streams typically separate into pools, riffles, and runs. The turbulence in each of these sections presents a strong direct physical control on gas processes via gas exchange rates, and an indirect biogeochemical control via affecting dissolved oxygen concentrations. So, we are also questioning how greenhouse gas related processes differ between pools and riffles in particular using a low gradient, warm Piedmont stream: New Hope Creek. |
Geological and biological methane and ancient carbon subsidies to freshwater food webs
NSF EAGER 2018-2023 PIs: Dr. DelVecchia and Dr. Jack Stanford 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 up to ten thousand years before present! We initially found this in Montana and Washington:
We questioned the possibility for geologic carbon sources to contribute to river food webs, so we then identified a river floodplain in Colorado which overlapped a warm springs and a carbon-rich shale formation under the EAGER grant. At this site, we found evidence of a geologic carbon contribution (CO2-C 15,000 years BP) to consumer biomass (dated up to 11,000 years BP) via chemoautotrophy and methanotrophy: most likely via ammonia or sulfur oxidation. This publication is nearing submission in June 2024, and we hope to share it with you soon! As part of the EAGER project, we also collaborated to understand how aquifer consumers might be able to access carbon resources produced at the oxic-anoxic interface. We 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.
|
|
|
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.
|
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.
- Thibault Datry, Julian D. Olden, Kendra Kaiser, Dan Allen, Ryan Burrows, Michelle H. Busch, Amanda DelVecchia, Walter K. Dodds, Megan Fork, Chelsea Little, Mathis L. Messager, Meryl Mims, Eric Moody, Romain Sarremejane, Amélie Truchy, Rachel Stubbington, Jonathan D. Tonkin, Richard H. Walker, Annika Walters, Songyan Yu, Sam Zipper, John Hammond. (2023) ‘Causes, responses, and implications of anthropogenic versus natural flow intermittence in river networks’. Bioscience.
- 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