Broadly, I am interested in how human activities are affecting the way that energy and nutrients cycle through ecosystems. My research aims to better characterize how reservoirs can affect the transport and transformation of carbon (C), nitrogen (N), and other biologically relevant elements.
My research also explores the potential role of management in affecting ecosystem function. Identifying reservoir management win-wins as well as trade-offs is critical as the quantity and quality of water becomes increasingly variable under a changing climate. Currently, I am working on a project to understand how conditions in Lake Powell (and the associated management of Glen Canyon Dam) are affecting ecosystem metabolism in the Colorado River.
Professional Experience
Oct 2016-present: Research ecologist, USGS Southwest Biological Science Center, Flagstaff, AZ
April 2020-2022: Raelyn Cole Editorial Fellow, Association for the Sciences of Limnology and Oceanography (ASLO)
February-May 2013: Policy Fellow, Army Corps Institute for Water Resources, Alexandria, VA
Education and Certifications
2016 - PhD, Environmental and Natural Resource Sciences, Washington State University, Vancouver
• Dissertation: "Patterns and controls on nitrogen removal and greenhouse gas production in reservoir"
2010 - M.S. in Environmental Science, Washington State University
2004 - B.A. in Environmental Studies, Vassar College
Science and Products
Lake Powell Research
Phosphorus, nitrogen, carbon, calcium, pH, and dissolved oxygen data from incubations of Colorado River water and sediment and associated ambient river water measurements
Rainbow trout growth data and growth covariate data from Glen Canyon, Colorado River, Arizona, 2012-2021
Limnology data from Lake Powell, desert southwest USA (ver. 2.0, Sept. 2023)
Proximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona.
Gross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam
Modeled and measured greenhouse gas emissions from Lake Powell and bathymetric analysis of tributary littoral habitat at different water levels
Carbon, nitrogen, and phosphorus content of adult emergent Diptera before and after a fire-storm sequence in the Colorado River near Shinumo Creek, Grand Canyon, AZ
Calcium, magnesium and total dissolved solids data as well as modeled salinity and mass balance estimates for Lake Powell, 1952-2017
Storms and pH of dam releases affect downstream phosphorus cycling in an arid regulated river
Linking ecosystem processes to consumer growth rates: Gross primary productivity as a driver of freshwater fish somatic growth in a resource-limited river
Inland water greenhouse gas budgets for RECCAP2: 1. State-of-the-art of global scale assessments
Inland water greenhouse gas budgets for RECCAP2: 2. Regionalization and homogenization of estimates
Declines in prey production during the collapse of a tailwater Rainbow Trout population are associated with changing reservoir conditions
Proceedings of the Fiscal Year 2022 Annual Reporting Meeting to the Glen Canyon Dam Adaptive Management Program
Appendix 1: Lake Powell water quality monitoring
Over half a century record of limnology data from Lake Powell, desert southwest United States: From reservoir filling to present day (1964–2021)
Drought related changes in water quality surpass effects of experimental flows on trout growth downstream of Lake Powell reservoir
Peer review by and for non-native English speakers: Interacting across international limnology societies
Taking steps to address inequities in open-access publishing through an early career publication honor
Little bugs, big data, and Colorado River adaptive management: Preliminary findings from the ongoing bug flow experiment at Glen Canyon Dam
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Lake Powell Research
Lake Powell is a large arid reservoir that represents about 70% of the water storage capacity for the Upper Colorado River Basin. It is the second largest reservoir in the United States by capacity (second only to Lake Mead). Lake Powell is an oligotrophic reservoir, which means that nutrient concentrations and algal production are generally low. This often results in very clear-water conditions... - Data
Phosphorus, nitrogen, carbon, calcium, pH, and dissolved oxygen data from incubations of Colorado River water and sediment and associated ambient river water measurements
Lake Powell retains most of the phosphorus that it receives, leading to downstream phosphorus limitation. These data were compiled to examine controls on phosphorus cycling below Lake Powell in the Colorado River and from storm inputs from the Paria River. Objectives of our study were to determine how several forms of phosphorus, both organic and inorganic, were cycled under varying dissolved oxygRainbow trout growth data and growth covariate data from Glen Canyon, Colorado River, Arizona, 2012-2021
These data are the primary data used to model rainbow trout growth in Glen Canyon. Fish growth data were collected from nighttime boat electrofishing field campaigns conducted five to six times per year in April, July, September, and January, from April 2012 through November 2021 for a total of 9798 observations of mark-recapture-based growth. Sampling was conducted in a five km reach in the lowerLimnology data from Lake Powell, desert southwest USA (ver. 2.0, Sept. 2023)
These data were compiled as part of a long-term (1964 - 2022) water quality monitoring program at Lake Powell. Objectives of our study were to release a consistent record of long-term water quality data. The 58-year limnology dataset captures some water quality parameters (temperature, salinity, major ions, total suspended solids) from reservoir filling to present day. It also contains a 38-year rProximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona.
Using a bioenergetic model, demographic data for the Rainbow Trout (Oncorhynchus mykiss) population were compiled and used to estimate total prey consumption in the Colorado River, Glen Canyon , AZ. Additionally, other data including invertebrate diet, drift, and benthic measurements were used to make generalized estimates of daily production rates for the most common benthic invertebrate taxa. ThGross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam
These data were compiled to model the effects of flow regime and bed grain size distributions on rates of gross primary production (GPP) in the Colorado River below Glen Canyon Dam, AZ, USA. The objectives of our study were to quantify daily and weekly scale effects of an experimental flow regime on GPP in the Colorado River. The experimental flow was conducted at Glen Canyon Dam from May-August iModeled and measured greenhouse gas emissions from Lake Powell and bathymetric analysis of tributary littoral habitat at different water levels
This data release contains model inputs used to estimate surface water greenhouse gas fluxes from two large arid reservoirs, Lake Powell and Lake Mead. The release also contains empirical, spatially explicit water quality and greenhouse gas data from a single field survey conducted in Lake Powell in July of 2017. Finally, this release contains surface area estimates of shallow (< 15m) tributary reCarbon, nitrogen, and phosphorus content of adult emergent Diptera before and after a fire-storm sequence in the Colorado River near Shinumo Creek, Grand Canyon, AZ
This dataset includes total phosphorus (TP), total nitrogen (TN), and total carbon (TC) concentrations as well as δ15N and δ13C composition, and overall C:N:P stoichiometry for adult emergent Diptera from the Colorado River, Grand Canyon, AZ. The samples were collected before and after a fire and subsequent storm occurred in the Shinumo Watershed, a tributary to the Colorado River in Northern ArizCalcium, magnesium and total dissolved solids data as well as modeled salinity and mass balance estimates for Lake Powell, 1952-2017
These data were compiled to quantify the role of Lake Powell in modulating salinity and reducing overall salt flux from the Upper Colorado River Basin downstream. In addition, these data were used to infer summertime calcite precipitation in Lake Powell (the major proposed sink for salt within the system). The Lake Powell Calcium Magnesium data contains summertime surface water calcium and magnesi - Publications
Filter Total Items: 20
Storms and pH of dam releases affect downstream phosphorus cycling in an arid regulated river
Reservoirs often bury phosphorus (P), leading to seasonal or persistent reductions in P supply to downstream rivers. Here we ask if observed variation in the chemistry of dam release waters stimulates downstream sediment P release and biological activity in an arid, oligotrophic system, the Colorado River below Lake Powell, Arizona, USA. We use bottle incubations to simulate a range of observed pHAuthorsBridget Deemer, Robin H. Reibold, Anna Fatta, Jessica R. Corman, Charles Yackulic, Sasha C. ReedLinking ecosystem processes to consumer growth rates: Gross primary productivity as a driver of freshwater fish somatic growth in a resource-limited river
Individual growth can exert strong controls on population dynamics and be constrained by resource acquisition rates. Difficulty in accurately quantifying resource availability over large spatial extents and at high temporal frequency often limits attempts to understand the extent that resources limit individual growth. Daily estimates of stream metabolism, including gross primary productivity (GPPAuthorsLindsay Erika Hansen, Charles Yackulic, Brett G. Dickson, Bridget Deemer, Rebecca J. BestInland water greenhouse gas budgets for RECCAP2: 1. State-of-the-art of global scale assessments
Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we review the state of the art in estimating inland water GHG budgets at global scale, which has substantially advanced since the first phaseAuthorsRonny Lauerwald, George H. Allen, Bridget Deemer, Shaoda Liu, Taylor Maavara, Peter Raymond, Lewis Alcott, David Bastviken, Adam Hastie, Meredith A. Holgerson, Matthew S. Johnson, Bernhard Lehner, Peirong Lin, Alessandra Marzadri, Lishan Ran, Hanqin Tian, Xiao Yang, Yuanzhi Yao, Pierre RegnierInland water greenhouse gas budgets for RECCAP2: 2. Regionalization and homogenization of estimates
Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we synthesize existing estimates of GHG emissions from streams, rivers, lakes and reservoirs, and homogenize them with regard to underlying glAuthorsRonny Lauerwald, George H. Allen, Bridget Deemer, Shaoda Liu, Taylor Maavara, Peter Raymond, Lewis Alcott, David Bastviken, Adam Hastie, Meredith A. Holgerson, Matthew S. Johnson, Bernhard Lehner, Peirong Lin, Alessandra Marzadri, Lishan Ran, Hanqin Tian, Xiao Yang, Yuanzhi Yao, Pierre RegnierDeclines in prey production during the collapse of a tailwater Rainbow Trout population are associated with changing reservoir conditions
ObjectiveUnderstanding how energy moves through food webs and limits productivity at various trophic levels is a central question in aquatic ecology and can provide insight into drivers of fish population dynamics since many fish populations are food limited. In this study, we seek to better understand what factors drove a decline of >85% in the number of Rainbow TroutOncorhynchus mykiss found inAuthorsMichael D. Yard, Charles Yackulic, Josh Korman, Michael Dodrill, Bridget DeemerProceedings of the Fiscal Year 2022 Annual Reporting Meeting to the Glen Canyon Dam Adaptive Management Program
(Hartwell) This report is prepared primarily to account for work conducted and products delivered in FY 2022 by GCMRC and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the Glen Canyon Dam Adaptive Management Program (GCDAMP). It includes a summary of accomplishments, modifications to work plans, results, and recommendations related to projects iAuthorsDavid Topping, Paul Grams, Emily C. Palmquist, Joel B. Sankey, Helen C. Fairley, Bridget Deemer, Charles Yackulic, Theodore Kennedy, Anya Metcalfe, Maria C. Dzul, David Ward, Mariah Aurelia Giardina, Lucas Bair, Thomas Gushue, Caitlin M. Andrews, Ronald E. Griffiths, David Dean, Keith Kohl, Michael J Moran, Nicholas Voichick, Thomas A. Sabol, Laura A. Tennant, Kimberly Dibble, Michael C. RungeAppendix 1: Lake Powell water quality monitoring
No abstract available.AuthorsBridget Deemer, Nicholas Voichick, Thomas A. Sabol, Caitlin M. Andrews, Bryce Anthony MihalevichOver half a century record of limnology data from Lake Powell, desert southwest United States: From reservoir filling to present day (1964–2021)
Lake Powell is a large water storage reservoir in the arid southwestern United States. Here, we present a 58-yr limnology dataset that captures water quality parameters from reservoir filling to present day (temperature, salinity, major ions, total suspended solids), as well as a 38-yr record of Secchi depth, and a ~ 30-yr record of nutrients, phytoplankton, and zooplankton assemblages. The dataseAuthorsBridget Deemer, Caitlin M. Andrews, Kristin E. Strock, Nicholas Voichick, James Hensleigh, John Beaver, Robert RadtkeDrought related changes in water quality surpass effects of experimental flows on trout growth downstream of Lake Powell reservoir
Flows released from reservoirs are often modified to mitigate the negative ecosystem effects of dams. We estimated the effects of two experimental flows, fall-timed floods and elimination of sub-daily variation in flows on weekends, on growth rates of rainbow trout (Oncorhynchus mykiss) in the Colorado River downstream from Glen Canyon Dam. Experimental flow effects were compared to effects of watAuthorsJosh Korman, Bridget Deemer, Charles Yackulic, Theodore Kennedy, Mariah Aurelia GiardinaPeer review by and for non-native English speakers: Interacting across international limnology societies
Scholarly peer review is critical to the scientific process, yet there are limited resources available for students, postdocs, and other early career researchers (ECRs) to learn how to perform effective and time-efficient review. The ASLO Raelyn Cole Editorial Fellows have developed several peer review training resources, including a webinar (https://www.youtube.com/watch?v=utntl1VGy5g), editorialAuthorsMary R. Gradoville, Bridget Deemer, Renee M. van DorstTaking steps to address inequities in open-access publishing through an early career publication honor
Access to resources—whether human, financial, or social—is a key indicator of research output and, in turn, academic career progression. However, resources are not equally distributed among scientists and disparities often stem from external factors. This reality is particularly impactful for early career researchers (ECRs) who have limited control over the resources available to them to advance tAuthorsScott Hotaling, Bridget Deemer, Kelsey Poulson-Ellestad, Laura J. FalkenbergLittle bugs, big data, and Colorado River adaptive management: Preliminary findings from the ongoing bug flow experiment at Glen Canyon Dam
The undammed Colorado River in Grand Canyon was characterized by spring snow-melt floods that sometimes exceeded 100,000 cubic feet per second (cfs). These were followed by occasional flash floods during summer monsoons, then by low flows from fall through early spring (Figure 1; Topping and others, 2003). This seasonally variable flow regime carried huge loads of sediment and was an important driAuthorsTheodore Kennedy, Anya Metcalfe, Bridget Deemer, Morgan Ford, Cheyenne Maxime Szydlo, Charles Yackulic, Jeffrey MuehlbauerNon-USGS Publications**
Deemer, B.R., J.A. Harrison, 2019, Summer redox dynamics in a eutrophic reservoir and sensitivity to a summer’s end drawdown event: Ecosystems, v: 22, p. 1618-1632, https://doi.org/10.1007/s10021-019-00362-0.Reed, D.C., B.R. Deemer, S. van Grinsven, and J.A. Harrison. 2017. Are elusive anaerobic pathways key methane sinks in eutrophic lakes and reservoirs? Biogeochemistry doi: 10.1007/s10533-017-0356-3Hayes, N.M, B.R. Deemer, J.R. Corman, N.R. Razavi, and K.E. Strock. 2017. Key differences between lakes and reservoirs modify climate signals: A case for a new conceptual model. Limnology and Oceanography Letters doi: 10.1002/lol2.10036Harrison, J.A., B.R. Deemer, M.K. Birchfield, and M.T. O’Malley. 2017. Reservoir water level drawdowns accelerate and amplify methane emission. Environmental Science & Technology doi: 10.1021/acs.est.6b03185Deemer, B.R., J.A. Harrison, S. Li, J. Beaulieu, T. DelSontro, N. Barros, M.A. dos Santos, J.F.Bezerra-Neto, S.M. Powers, and J.A. Vonk. 2016. Greenhouse gas emissions from reservoir water surfaces: A new global synthesis. BioScience doi: 10.1093/biosci/biw117Deemer, B.R., S.M. Henderson, and J.A. Harrison. 2015. Chemical mixing in the bottom boundary layer of a eutrophic reservoir: the effects of internal seiching on nitrogen dynamics. Limnology and Oceanography 60: 1642-1655.Deemer, B.R., K.E. Goodwin, T.A. Lee, M.K. Birchfield, K. Dallavis, J. Emerson, D. Freeman, E. Henry, L. Wynn, and J.A. Harrison. 2012. Elevated nitrogen and phosphorus concentrations in urbanizing southwest Washington streams. Northwest Science 86: 237-247.Henderson, S.M., and B.R. Deemer. 2012. Vertical propagation of lakewide internal waves. Geophysical Research Letters 39: doi:10.1029/2011GL050534.Deemer, B.R., J.A. Harrison, and E.W. Whitling. 2011. Microbial dinitrogen and nitrous oxide production in a small eutrophic reservoir: an in situ approach to quantifying hypolimnetic process rates. Limnology and Oceanography 56: 1189-1199.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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