M. Alisa Mast (Former Employee)
Science and Products
Filter Total Items: 96
Science needs for continued development of total nitrogen deposition budgets in the United States Science needs for continued development of total nitrogen deposition budgets in the United States
The objectives of this white paper are to describe the state of the science with respect to total Nr deposition budgets in North America and the research needed to improve these budgets from both a measurement and modeling standpoint. The document is intended to serve as a plan for TDep research activities but also, more broadly, to provide program managers, natural resource managers...
Authors
Gregory A. Wetherbee, Pamela H. Templar, Richard V. Pouyat, Stephen M. Decina, Brian M. Kerschner, Thomas H. Whitlow, Pamela E. Padgett, Donna B. Schwede, Jill Baron, David Clow, M. Alisa Mast, Graham A. Sexstone, Kristi H. Morris
Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah
The purpose of this report is to evaluate the use of site-specific regression models to estimate metal concentrations at nine U.S. Geological Survey streamflow-gaging stations on the Animas and San Juan Rivers in Colorado, New Mexico, and Utah. Downstream users could use these regression models to determine if metal concentrations are elevated and pose a risk to water supplies...
Authors
M. Alisa Mast
Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States
Transit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in...
Authors
David W. Clow, M. Alisa Mast, James O. Sickman
Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes
Variation in source areas and source types of atmospheric nitrogen (N) deposition to high-elevation ecosystems in the Rocky Mountains were evaluated using spatially and temporally distributed N isotope data from atmospheric deposition networks for 1995-2016. This unique dataset links N in wet deposition and snowpack to mobile and stationary emissions sources, and enhances understanding...
Authors
Leora Nanus, Donald H. Campbell, Christopher M.B. Lehmann, M. Alisa Mast
Estimation of salt loads for the Dolores River in the Paradox Valley, Colorado, 1980–2015 Estimation of salt loads for the Dolores River in the Paradox Valley, Colorado, 1980–2015
Regression models that relate total dissolved solids (TDS) concentrations to specific conductance were used to estimate salt loads for two sites on the Dolores River in the Paradox Valley in western Colorado. The salt-load estimates will be used by the Bureau of Reclamation to evaluate salt loading to the river coming from the Paradox Valley and the effect of the Paradox Valley Unit (PVU...
Authors
M. Alisa Mast
Climate-change signals in national atmospheric deposition program precipitation data Climate-change signals in national atmospheric deposition program precipitation data
National Atmospheric Deposition Program (NADP)/National Trends Network precipitation type, snow-season duration, and annual timing of selected chemical wet-deposition maxima vary with latitude and longitude within a 35-year (1979–2013) data record for the contiguous United States and Alaska. From the NADP data collected within the region bounded by 35.6645°–48.782° north latitude and 124...
Authors
Gregory A. Wetherbee, M. Alisa Mast
Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA
Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and...
Authors
Taylor J. Mills, M. Alisa Mast, Judith C. Thomas, Gabrielle L. Keith
Spatiotemporal patterns of mercury accumulation in lake sediments of western North America Spatiotemporal patterns of mercury accumulation in lake sediments of western North America
For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation...
Authors
Paul Drevnick, Colin A. Cooke, Daniella Barraza, Jules M. Blais, Kenneth Coale, Brian F. Cumming, Chris Curtis, Biplob Das, William F. Donahue, Collin A. Eagles-Smith, Daniel R. Engstrom, William F. Fitzgerald, Chad V. Furl, John R. Gray, Roland I. Hall, Togwell A. Jackson, Kathleen R. Laird, W. Lyle Lockhart, Robie W. Macdonald, M. Alisa Mast, Callie Mathieu, Derek C.G. Muir, Peter Outridge, Scott Reinemann, Sarah E. Rothenberg, Ana Carolina Ruiz-Fernandex, Louis, Rhea Sanders, Hamed Sanei, Elliott Skierszkan, Peter C. Van Metre, Timothy Veverica, Johan A. Wiklund, Brent B. Wolfe
Water-quality response to a high-elevation wildfire in the Colorado Front Range Water-quality response to a high-elevation wildfire in the Colorado Front Range
Water quality of the Big Thompson River in the Front Range of Colorado was studied for 2 years following a high‐elevation wildfire that started in October 2012 and burned 15% of the watershed. A combination of fixed‐interval sampling and continuous water‐quality monitors was used to examine the timing and magnitude of water‐quality changes caused by the wildfire. Prefire water quality...
Authors
M. Alisa Mast, Sheila F. Murphy, David W. Clow, Colin A. Penn, Graham A. Sexstone
Isotopes in North American Rocky Mountain snowpack 1993–2014 Isotopes in North American Rocky Mountain snowpack 1993–2014
We present ∼1300 new isotopic measurements (δ18O and δ2H) from a network of snowpack sites in the Rocky Mountains that have been sampled since 1993. The network includes 177 locations where depth-integrated snow samples are collected each spring near peak accumulation. At 57 of these locations snowpack samples were obtained for 10–21 years and their isotopic measurements provide...
Authors
Lesleigh Anderson, Max Berkelhammer, M. Alisa Mast
2013 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park 2013 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park
In 2004, multiple agencies including the Colorado Department of Public Health and Environment (CDPHE), the National Park Service (NPS), and the U.S. Environmental Protection Agency (U.S. EPA) met to address the effects and trends of nitrogen deposition and related air quality issues at Rocky Mountain National Park (RMNP). These agencies signed a Memorandum of Understanding (MOU) to...
Authors
Kristi Morris, M. Alisa Mast, David W. Clow, Gregory A. Wetherbee, Jill Baron, Curt Taipale, Tamara Blett, David A. Gay, Daniel Bowker
Links between N deposition and nitrate export from a high-elevation watershed in the Colorado Front Range Links between N deposition and nitrate export from a high-elevation watershed in the Colorado Front Range
Long-term patterns of stream nitrate export and atmospheric N deposition were evaluated over three decades in Loch Vale, a high-elevation watershed in the Colorado Front Range. Stream nitrate concentrations increased in the early 1990s, peaked in the mid-2000s, and have since declined by over 40%, coincident with trends in nitrogen oxide emissions over the past decade. Similarities in...
Authors
M. Alisa Mast, David W. Clow, Jill Baron, Gregory A. Wetherbee
Science and Products
Filter Total Items: 96
Science needs for continued development of total nitrogen deposition budgets in the United States Science needs for continued development of total nitrogen deposition budgets in the United States
The objectives of this white paper are to describe the state of the science with respect to total Nr deposition budgets in North America and the research needed to improve these budgets from both a measurement and modeling standpoint. The document is intended to serve as a plan for TDep research activities but also, more broadly, to provide program managers, natural resource managers...
Authors
Gregory A. Wetherbee, Pamela H. Templar, Richard V. Pouyat, Stephen M. Decina, Brian M. Kerschner, Thomas H. Whitlow, Pamela E. Padgett, Donna B. Schwede, Jill Baron, David Clow, M. Alisa Mast, Graham A. Sexstone, Kristi H. Morris
Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah
The purpose of this report is to evaluate the use of site-specific regression models to estimate metal concentrations at nine U.S. Geological Survey streamflow-gaging stations on the Animas and San Juan Rivers in Colorado, New Mexico, and Utah. Downstream users could use these regression models to determine if metal concentrations are elevated and pose a risk to water supplies...
Authors
M. Alisa Mast
Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States
Transit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in...
Authors
David W. Clow, M. Alisa Mast, James O. Sickman
Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes
Variation in source areas and source types of atmospheric nitrogen (N) deposition to high-elevation ecosystems in the Rocky Mountains were evaluated using spatially and temporally distributed N isotope data from atmospheric deposition networks for 1995-2016. This unique dataset links N in wet deposition and snowpack to mobile and stationary emissions sources, and enhances understanding...
Authors
Leora Nanus, Donald H. Campbell, Christopher M.B. Lehmann, M. Alisa Mast
Estimation of salt loads for the Dolores River in the Paradox Valley, Colorado, 1980–2015 Estimation of salt loads for the Dolores River in the Paradox Valley, Colorado, 1980–2015
Regression models that relate total dissolved solids (TDS) concentrations to specific conductance were used to estimate salt loads for two sites on the Dolores River in the Paradox Valley in western Colorado. The salt-load estimates will be used by the Bureau of Reclamation to evaluate salt loading to the river coming from the Paradox Valley and the effect of the Paradox Valley Unit (PVU...
Authors
M. Alisa Mast
Climate-change signals in national atmospheric deposition program precipitation data Climate-change signals in national atmospheric deposition program precipitation data
National Atmospheric Deposition Program (NADP)/National Trends Network precipitation type, snow-season duration, and annual timing of selected chemical wet-deposition maxima vary with latitude and longitude within a 35-year (1979–2013) data record for the contiguous United States and Alaska. From the NADP data collected within the region bounded by 35.6645°–48.782° north latitude and 124...
Authors
Gregory A. Wetherbee, M. Alisa Mast
Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA
Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and...
Authors
Taylor J. Mills, M. Alisa Mast, Judith C. Thomas, Gabrielle L. Keith
Spatiotemporal patterns of mercury accumulation in lake sediments of western North America Spatiotemporal patterns of mercury accumulation in lake sediments of western North America
For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation...
Authors
Paul Drevnick, Colin A. Cooke, Daniella Barraza, Jules M. Blais, Kenneth Coale, Brian F. Cumming, Chris Curtis, Biplob Das, William F. Donahue, Collin A. Eagles-Smith, Daniel R. Engstrom, William F. Fitzgerald, Chad V. Furl, John R. Gray, Roland I. Hall, Togwell A. Jackson, Kathleen R. Laird, W. Lyle Lockhart, Robie W. Macdonald, M. Alisa Mast, Callie Mathieu, Derek C.G. Muir, Peter Outridge, Scott Reinemann, Sarah E. Rothenberg, Ana Carolina Ruiz-Fernandex, Louis, Rhea Sanders, Hamed Sanei, Elliott Skierszkan, Peter C. Van Metre, Timothy Veverica, Johan A. Wiklund, Brent B. Wolfe
Water-quality response to a high-elevation wildfire in the Colorado Front Range Water-quality response to a high-elevation wildfire in the Colorado Front Range
Water quality of the Big Thompson River in the Front Range of Colorado was studied for 2 years following a high‐elevation wildfire that started in October 2012 and burned 15% of the watershed. A combination of fixed‐interval sampling and continuous water‐quality monitors was used to examine the timing and magnitude of water‐quality changes caused by the wildfire. Prefire water quality...
Authors
M. Alisa Mast, Sheila F. Murphy, David W. Clow, Colin A. Penn, Graham A. Sexstone
Isotopes in North American Rocky Mountain snowpack 1993–2014 Isotopes in North American Rocky Mountain snowpack 1993–2014
We present ∼1300 new isotopic measurements (δ18O and δ2H) from a network of snowpack sites in the Rocky Mountains that have been sampled since 1993. The network includes 177 locations where depth-integrated snow samples are collected each spring near peak accumulation. At 57 of these locations snowpack samples were obtained for 10–21 years and their isotopic measurements provide...
Authors
Lesleigh Anderson, Max Berkelhammer, M. Alisa Mast
2013 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park 2013 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park
In 2004, multiple agencies including the Colorado Department of Public Health and Environment (CDPHE), the National Park Service (NPS), and the U.S. Environmental Protection Agency (U.S. EPA) met to address the effects and trends of nitrogen deposition and related air quality issues at Rocky Mountain National Park (RMNP). These agencies signed a Memorandum of Understanding (MOU) to...
Authors
Kristi Morris, M. Alisa Mast, David W. Clow, Gregory A. Wetherbee, Jill Baron, Curt Taipale, Tamara Blett, David A. Gay, Daniel Bowker
Links between N deposition and nitrate export from a high-elevation watershed in the Colorado Front Range Links between N deposition and nitrate export from a high-elevation watershed in the Colorado Front Range
Long-term patterns of stream nitrate export and atmospheric N deposition were evaluated over three decades in Loch Vale, a high-elevation watershed in the Colorado Front Range. Stream nitrate concentrations increased in the early 1990s, peaked in the mid-2000s, and have since declined by over 40%, coincident with trends in nitrogen oxide emissions over the past decade. Similarities in...
Authors
M. Alisa Mast, David W. Clow, Jill Baron, Gregory A. Wetherbee