Marjorie Brooks - Academia.edu (original) (raw)
Papers by Marjorie Brooks
Please join us for a lively discussion and question and answer session about water resource caree... more Please join us for a lively discussion and question and answer session about water resource careers. A panel of experts with diverse training and experience in the profession will discuss coursework and training recommendations, strategies for job searching, interviewing tips, and typical career tracks in government agencies, private consulting, water supply industry, academia, regional planning, and non-profit organizations, as well as future directions in water resources employment. Our panel will include:
Four species of threatened or declining eider ducks that nest in the Arctic migrate through the n... more Four species of threatened or declining eider ducks that nest in the Arctic migrate through the northeast Chukchi Sea, where anticipated industrial development may require prioritizing areas for conservation. In this nearshore corridor (10–40 m depth), the eiders' access to benthic prey during the spring is restricted to variable areas of open water within sea ice. For the most abundant species, the king eider (Somateria spectabilis), stable isotopes in blood cells, muscle, and potential prey indicate that these eiders ate mainly bivalves when traversing this corridor. Bivalves there were much smaller than the same taxa in deeper areas of the northern Bering Sea, possibly due to higher mortality rates caused by ice scour in shallow water; future decrease in seasonal duration of fast ice may increase this effect. Computer simulations suggested that if these eiders forage for greater than 15 hours per day, they can feed profitably at bivalve densities greater than 200 meters\0022 ...
Stable isotope values (δ13C and δ15N) of ice algae, suspended particulate matter, sediments, and ... more Stable isotope values (δ13C and δ15N) of ice algae, suspended particulate matter, sediments, and deposit-feeding invertebrates from the northern Bering Sea.
Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920s hypothetically tr... more Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920s hypothetically triggered a behaviorally-mediated trophic cascade in which elk (Cervus elaphus), released from the fear of wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast areas of meadow-wetland complexes transitioned to grass-lodgepole systems. The importance of beaver (Castor canadensis) in wetland losses has received less attention. Beaver abandoned most of the GYE by the 1950s, possibly due to resource limitations. Researchers from Colorado State University established an experimental system for Long Term Environmental Research in Biology (LTREB) along several streams in the Lamar Valley of Yellowstone sixteen years ago. To evaluate effects of hydrologic changes and elk browsing on productivity of willows (Salix spp.) and state transition, they built small experimental dams with browsing exclosures. In 2015, beaver began recolonizing the region. I am investigating how their...
The UW National Parks Service Research Station Annual Reports
Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920shypothetically tri... more Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920shypothetically triggered a behaviorally-mediated trophic cascade in which elk (Cervus elaphus), released from the fear of wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast areas of meadow-wetland complexes transitioned to grass-lodgepole systems. The importance of beaver (Castor canadensis) in wetland losses has received less attention. Beaver abandoned most of the GYE by the 1950s, possibly due to resource limitations. Researchers from Colorado State University established an experimental system for Long Term Environmental Research in Biology (LTREB) along several streams in the Lamar Valley of Yellowstone sixteen years ago. To evaluate effects of hydrologic changes and elk browsing on productivity of willows (Salix spp.) and state transition, they built small experimental dams with browsing exclosures. In 2015, beaver began recolonizing the region. I am investigating how their ...
Exposure and Health, 2016
This study identifies risk perception and actual health risks from exposure to metals in fish fro... more This study identifies risk perception and actual health risks from exposure to metals in fish from the Tisza River Basin of central Europe. Mining in the region has chronically introduced metals; however, two major mine-tailings spill in 2000 contributed an estimated 240,000 m3 of wastewater and tailings contaminated with cyanide and metals to the system. In 2013 and 2014, water and fish (N = 99) collected from the lower Tisza River Basin were analyzed for cadmium, copper, lead, nickel, and zinc. Concurrently, surveys (N = 45) collected near sampling sites assessed fish-consumption patterns and risk perception. Metals in water exceeded regulatory criteria at multiple sites; however, metals are not bioaccumulating to a degree of undue concern in fish as bioaccumulation factors were below 1. Average concentrations of metals in fish fillets (µg g−1 wet weight) in decreasing order were zinc (8.8) > copper (0.14) > nickel (0.06) > lead (0.02) > cadmium (0.004). Fillets were within European Food Safety Authority recommendations; however, the Target Hazard Quotient for lead was elevated at 1.5 for average consumers and 3.5 for people who consume fish twice weekly. The majority of survey participants were unconcerned with local fish consumption (87 %), citing the “clean” appearance of fishing locations. Participants also reported relatively low fish consumption, with most (76 %) eating basin fish once a week or less. While our study indicates fish are generally safe for human consumption, waters are polluted, suggesting that local fishing populations may be at risk from unseen pollutants and highlighting the need for monitoring and notification systems.
Environmental Toxicology and Chemistry, 2015
Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or ... more Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. In support of a study on pyrethroid impacts to Chinook salmon and steelhead trout in the American River (Sacramento, California, USA), 96-h median effective concentration (EC50) and median lethal concentration (LC50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, including a chironomid, caddisflies, mayflies, and stoneflies. A laboratory was constructed on the banks of the American River to expose macroinvertebrates, Chinook salmon, and steelhead trout to flow-through river water containing urban runoff during storm events. Bifenthrin from urban runoff was found in river water following 5 rain events, reaching 14.6 ng/L. Mortality to the exposed salmonids was not observed, and sublethal effects were not seen in vitellogenin or sex steroid levels. Indirect effects via toxicity to salmonid prey are possible. Mortality to Hyalella azteca, a potential prey, was observed in every event tested, and peak bifenthrin concentrations were comparable to the 96-h EC50 of the caddisfly, Hydropsyche sp., the most important prey species on a biomass basis for American River Chinook salmon. The other invertebrates tested had EC50s exceeding bifenthrin concentrations seen in the American River, though could potentially be at risk at concentrations previously reported in smaller urban tributaries. Environ Toxicol Chem 2015;34:649-657. © 2014 SETAC.
Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or ... more Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. In support of a study on pyrethroid impacts to Chinook salmon and steelhead trout in the American River (Sacramento, California, USA), 96-h median effective concentration (EC50) and median lethal concentration (LC50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, including a chironomid, caddisflies, mayflies, and stoneflies. A laboratory was constructed on the banks of the American River to expose macroinvertebrates, Chinook salmon, and steelhead trout to flow-through river water containing urban runoff during storm events. Bifenthrin from urban runoff was found in river water following 5 rain events, reaching 14.6 ng/L. Mortality to the exposed salmonids was not observed, and sublethal effects were not seen in vitellogenin or sex steroid levels. Indirect effects via toxicity to salmonid prey are possible. Mortality to Hyalella azteca, a potential prey, was observed in every event tested, and peak bifenthrin concentrations were comparable to the 96-h EC50 of the caddisfly, Hydropsyche sp., the most important prey species on a biomass basis for American River Chinook salmon. The other invertebrates tested had EC50s exceeding bifenthrin concentrations seen in the American River, though could potentially be at risk at concentrations previously reported in smaller urban tributaries. Environ Toxicol Chem 2015;34:649-657. © 2014 SETAC.
Ecological Assessment of Selenium in the Aquatic Environment, 2010
Marine Ecology Progress Series, 2013
Limnology and Oceanography, 2007
Integrated Environmental Assessment and Management, 2011
Environmental Toxicology and Chemistry, 2008
Limnology and oceanography, 2007
Canadian Journal of Fisheries and Aquatic Sciences, 2007
Copper (Cu) complexation with natural dissolved organic matter (DOM) mitigates Cu bioavailability... more Copper (Cu) complexation with natural dissolved organic matter (DOM) mitigates Cu bioavailability to aquatic biota by decreasing the activity of the cupric ion ({Cu2+}). However, DOM is photochemically unstable. In a previous study, we demonstrated that irradiation (~13 days sunlight) of DOM collected from a river decreased its binding-site density for Cu by 45%, but increased binding-site density in wetland DOM by 147%. Binding-site densities correlated positively with ketones and aldehydes (C-II groups). Herein, we determined the mortality of larval fathead minnows (FHM; Pimephales promelas) as a function of {Cu2+} in 96 h static-renewal toxicity tests without DOM. Next, we calculated {Cu2+} in control and photooxidized DOM and then predicted mortality of larval FHM in toxicity tests. Observed mortalities agreed with predictions (r2 ≈ 0.96) in treatments with lowest binding-site densities and proportions of C-II groups (highest {Cu2+}). However, treatments with ~50% lower {Cu2+}, ...
Environmental …, 2008
The biotic ligand model (BLM) for the acute toxicity of cationic metals to aquatic organisms inco... more The biotic ligand model (BLM) for the acute toxicity of cationic metals to aquatic organisms incorporates the toxicity-modifying effects of dissolved organic matter (DOM), but the default parameterization (ie, assuming 10% of DOM is humic acid) does not differentiate DOM from different ...
Please join us for a lively discussion and question and answer session about water resource caree... more Please join us for a lively discussion and question and answer session about water resource careers. A panel of experts with diverse training and experience in the profession will discuss coursework and training recommendations, strategies for job searching, interviewing tips, and typical career tracks in government agencies, private consulting, water supply industry, academia, regional planning, and non-profit organizations, as well as future directions in water resources employment. Our panel will include:
Four species of threatened or declining eider ducks that nest in the Arctic migrate through the n... more Four species of threatened or declining eider ducks that nest in the Arctic migrate through the northeast Chukchi Sea, where anticipated industrial development may require prioritizing areas for conservation. In this nearshore corridor (10–40 m depth), the eiders' access to benthic prey during the spring is restricted to variable areas of open water within sea ice. For the most abundant species, the king eider (Somateria spectabilis), stable isotopes in blood cells, muscle, and potential prey indicate that these eiders ate mainly bivalves when traversing this corridor. Bivalves there were much smaller than the same taxa in deeper areas of the northern Bering Sea, possibly due to higher mortality rates caused by ice scour in shallow water; future decrease in seasonal duration of fast ice may increase this effect. Computer simulations suggested that if these eiders forage for greater than 15 hours per day, they can feed profitably at bivalve densities greater than 200 meters\0022 ...
Stable isotope values (δ13C and δ15N) of ice algae, suspended particulate matter, sediments, and ... more Stable isotope values (δ13C and δ15N) of ice algae, suspended particulate matter, sediments, and deposit-feeding invertebrates from the northern Bering Sea.
Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920s hypothetically tr... more Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920s hypothetically triggered a behaviorally-mediated trophic cascade in which elk (Cervus elaphus), released from the fear of wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast areas of meadow-wetland complexes transitioned to grass-lodgepole systems. The importance of beaver (Castor canadensis) in wetland losses has received less attention. Beaver abandoned most of the GYE by the 1950s, possibly due to resource limitations. Researchers from Colorado State University established an experimental system for Long Term Environmental Research in Biology (LTREB) along several streams in the Lamar Valley of Yellowstone sixteen years ago. To evaluate effects of hydrologic changes and elk browsing on productivity of willows (Salix spp.) and state transition, they built small experimental dams with browsing exclosures. In 2015, beaver began recolonizing the region. I am investigating how their...
The UW National Parks Service Research Station Annual Reports
Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920shypothetically tri... more Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920shypothetically triggered a behaviorally-mediated trophic cascade in which elk (Cervus elaphus), released from the fear of wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast areas of meadow-wetland complexes transitioned to grass-lodgepole systems. The importance of beaver (Castor canadensis) in wetland losses has received less attention. Beaver abandoned most of the GYE by the 1950s, possibly due to resource limitations. Researchers from Colorado State University established an experimental system for Long Term Environmental Research in Biology (LTREB) along several streams in the Lamar Valley of Yellowstone sixteen years ago. To evaluate effects of hydrologic changes and elk browsing on productivity of willows (Salix spp.) and state transition, they built small experimental dams with browsing exclosures. In 2015, beaver began recolonizing the region. I am investigating how their ...
Exposure and Health, 2016
This study identifies risk perception and actual health risks from exposure to metals in fish fro... more This study identifies risk perception and actual health risks from exposure to metals in fish from the Tisza River Basin of central Europe. Mining in the region has chronically introduced metals; however, two major mine-tailings spill in 2000 contributed an estimated 240,000 m3 of wastewater and tailings contaminated with cyanide and metals to the system. In 2013 and 2014, water and fish (N = 99) collected from the lower Tisza River Basin were analyzed for cadmium, copper, lead, nickel, and zinc. Concurrently, surveys (N = 45) collected near sampling sites assessed fish-consumption patterns and risk perception. Metals in water exceeded regulatory criteria at multiple sites; however, metals are not bioaccumulating to a degree of undue concern in fish as bioaccumulation factors were below 1. Average concentrations of metals in fish fillets (µg g−1 wet weight) in decreasing order were zinc (8.8) > copper (0.14) > nickel (0.06) > lead (0.02) > cadmium (0.004). Fillets were within European Food Safety Authority recommendations; however, the Target Hazard Quotient for lead was elevated at 1.5 for average consumers and 3.5 for people who consume fish twice weekly. The majority of survey participants were unconcerned with local fish consumption (87 %), citing the “clean” appearance of fishing locations. Participants also reported relatively low fish consumption, with most (76 %) eating basin fish once a week or less. While our study indicates fish are generally safe for human consumption, waters are polluted, suggesting that local fishing populations may be at risk from unseen pollutants and highlighting the need for monitoring and notification systems.
Environmental Toxicology and Chemistry, 2015
Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or ... more Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. In support of a study on pyrethroid impacts to Chinook salmon and steelhead trout in the American River (Sacramento, California, USA), 96-h median effective concentration (EC50) and median lethal concentration (LC50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, including a chironomid, caddisflies, mayflies, and stoneflies. A laboratory was constructed on the banks of the American River to expose macroinvertebrates, Chinook salmon, and steelhead trout to flow-through river water containing urban runoff during storm events. Bifenthrin from urban runoff was found in river water following 5 rain events, reaching 14.6 ng/L. Mortality to the exposed salmonids was not observed, and sublethal effects were not seen in vitellogenin or sex steroid levels. Indirect effects via toxicity to salmonid prey are possible. Mortality to Hyalella azteca, a potential prey, was observed in every event tested, and peak bifenthrin concentrations were comparable to the 96-h EC50 of the caddisfly, Hydropsyche sp., the most important prey species on a biomass basis for American River Chinook salmon. The other invertebrates tested had EC50s exceeding bifenthrin concentrations seen in the American River, though could potentially be at risk at concentrations previously reported in smaller urban tributaries. Environ Toxicol Chem 2015;34:649-657. © 2014 SETAC.
Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or ... more Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. In support of a study on pyrethroid impacts to Chinook salmon and steelhead trout in the American River (Sacramento, California, USA), 96-h median effective concentration (EC50) and median lethal concentration (LC50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, including a chironomid, caddisflies, mayflies, and stoneflies. A laboratory was constructed on the banks of the American River to expose macroinvertebrates, Chinook salmon, and steelhead trout to flow-through river water containing urban runoff during storm events. Bifenthrin from urban runoff was found in river water following 5 rain events, reaching 14.6 ng/L. Mortality to the exposed salmonids was not observed, and sublethal effects were not seen in vitellogenin or sex steroid levels. Indirect effects via toxicity to salmonid prey are possible. Mortality to Hyalella azteca, a potential prey, was observed in every event tested, and peak bifenthrin concentrations were comparable to the 96-h EC50 of the caddisfly, Hydropsyche sp., the most important prey species on a biomass basis for American River Chinook salmon. The other invertebrates tested had EC50s exceeding bifenthrin concentrations seen in the American River, though could potentially be at risk at concentrations previously reported in smaller urban tributaries. Environ Toxicol Chem 2015;34:649-657. © 2014 SETAC.
Ecological Assessment of Selenium in the Aquatic Environment, 2010
Marine Ecology Progress Series, 2013
Limnology and Oceanography, 2007
Integrated Environmental Assessment and Management, 2011
Environmental Toxicology and Chemistry, 2008
Limnology and oceanography, 2007
Canadian Journal of Fisheries and Aquatic Sciences, 2007
Copper (Cu) complexation with natural dissolved organic matter (DOM) mitigates Cu bioavailability... more Copper (Cu) complexation with natural dissolved organic matter (DOM) mitigates Cu bioavailability to aquatic biota by decreasing the activity of the cupric ion ({Cu2+}). However, DOM is photochemically unstable. In a previous study, we demonstrated that irradiation (~13 days sunlight) of DOM collected from a river decreased its binding-site density for Cu by 45%, but increased binding-site density in wetland DOM by 147%. Binding-site densities correlated positively with ketones and aldehydes (C-II groups). Herein, we determined the mortality of larval fathead minnows (FHM; Pimephales promelas) as a function of {Cu2+} in 96 h static-renewal toxicity tests without DOM. Next, we calculated {Cu2+} in control and photooxidized DOM and then predicted mortality of larval FHM in toxicity tests. Observed mortalities agreed with predictions (r2 ≈ 0.96) in treatments with lowest binding-site densities and proportions of C-II groups (highest {Cu2+}). However, treatments with ~50% lower {Cu2+}, ...
Environmental …, 2008
The biotic ligand model (BLM) for the acute toxicity of cationic metals to aquatic organisms inco... more The biotic ligand model (BLM) for the acute toxicity of cationic metals to aquatic organisms incorporates the toxicity-modifying effects of dissolved organic matter (DOM), but the default parameterization (ie, assuming 10% of DOM is humic acid) does not differentiate DOM from different ...