Jacob A Fleck
Jacob A Fleck - California Water Science Center
Science and Products
Filter Total Items: 15
Data from the development and testing of a multiparameter standard solution for fluorescent dissolved organic matter (fDOM) and algal fluorescence (fChl)
Optical sensors measuring fluorescent dissolved organic matter (fDOM) are increasingly being used in water quality studies because they provide proxy measurements for dissolved organic matter concentrations (DOC). Similarly, chlorophyll-a (chl-a) fluorescence sensors have gained popularity as a means to measure phytoplankton concentration, biomass, and even primary productivity using various appro
Surface-Water Geochemistry of Mercury, Methylmercury, Nutrients, and other Constituents in Clear Lake, Lake County, California, July 2019
Clear Lake is a 180 km2 freshwater lake located in the California Coast Range, approximately 120 km northwest of Sacramento. The lake supports a wide variety of fish and bird species and is a very popular sport-fishing destination. However, fish consumption advisories associated with mercury (Hg) contamination exist for several popular recreational species. The lake is comprised of three main regi
Geochemistry of shallow sediment including mercury, methylmercury and other constituents in the Cache Creek Settling Basin, Yolo County, California, 2010-16
The Cache Creek Settling Basin (CCSB) is a 13.3 km2 leveed basin located at the terminal drainage of the Cache Creek watershed, immediately NE of the town of Woodland (Yolo County), California and approximately 18 km NW of Sacramento, California. The basin was constructed by the U.S. Army Corps of Engineers (completed in 1937 and modified in 1993) for the purpose of trapping suspended sediment tra
Filter Total Items: 36
Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation
Advances in spectroscopic techniques have led to an increase in the use of optical properties (absorbance and fluorescence) to assess dissolved organic matter (DOM) composition and infer sources and processing. However, little information is available to assess the impact of biological and photolytic processing on the optical properties of original DOM source materials. We measured changes in comm
Authors
Angela Hansen, Tamara E. C. Kraus, Brian Pellerin, Jacob Fleck, Bryan D. Downing, Brian A. Bergamaschi
Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada
Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western United States (US) and Canada, a region defined by e
Authors
Collin A. Eagles-Smith, Joshua T. Ackerman, James J. Willacker, Michael T. Tate, Michelle A. Lutz, Jacob Fleck, A. Robin Stewart, James G. Wiener, David C. Evers, Jesse M. Lepak, Jay A. Davis, Colleen Flanagan Pritz
Mercury, monomethyl mercury, and dissolved organic carbon concentrations in surface water entering and exiting constructed wetlands treated with metal-based coagulants, Twitchell Island, California
Coagulation with metal-based salts is a practice commonly employed by drinking-water utilities to decrease particle and dissolved organic carbon concentrations in water. In addition to decreasing dissolved organic carbon concentrations, the effectiveness of iron- and aluminum-based coagulants for decreasing dissolved concentrations both of inorganic and monomethyl mercury in water was demonstrated
Authors
Elizabeth B. Stumpner, Tamara E.C. Kraus, Jacob A. Fleck, Angela M. Hansen, Sandra M. Bachand, William R. Horwath, John F. DeWild, David P. Krabbenhoft, Philip A.M. Bachand
Experimental dosing of wetlands with coagulants removes mercury from surface water and decreases mercury bioaccumulation in fish
Mercury pollution is widespread globally, and strategies for managing mercury contamination in aquatic environments are necessary. We tested whether coagulation with metal-based salts could remove mercury from wetland surface waters and decrease mercury bioaccumulation in fish. In a complete randomized block design, we constructed nine experimental wetlands in California’s Sacramento–San Joaquin D
Authors
Joshua T. Ackerman, Tamara E.C. Kraus, Jacob A. Fleck, David P. Krabbenhoft, William R. Horwarth, Sandra M. Bachand, Mark P. Herzog, C. Alex Hartman, Philip A.M. Bachand
Wetland management and rice farming strategies to decrease methylmercury bioaccumulation and loads from the Cosumnes River Preserve, California
We evaluated mercury (Hg) concentrations in caged fish (deployed for 30 days) and water from agricultural wetland (rice fields), managed wetland, slough, and river habitats in the Cosumnes River Preserve, California. We also implemented experimental hydrological regimes on managed wetlands and post-harvest rice straw management techniques on rice fields in order to evaluate potential Best Manageme
Authors
Collin A. Eagles-Smith, Joshua T. Ackerman, Jacob Fleck, Lisamarie Windham-Myers, Harry McQuillen, Wes Heim
Methylmercury production in sediment from agricultural and non-agricultural wetlands in the Yolo Bypass, California, USA
As part of a larger study of mercury (Hg) biogeochemistry and bioaccumulation in agricultural (rice growing) and non-agricultural wetlands in California's Central Valley, USA, seasonal and spatial controls on methylmercury (MeHg) production were examined in surface sediment. Three types of shallowly-flooded agricultural wetlands (white rice, wild rice, and fallow fields) and two types of managed (
Authors
Mark Marvin-DiPasquale, Lisamarie Windham-Myers, Jennifer L. Agee, Evangelos Kakouros, Le H. Kieu, Jacob A. Fleck, Charles N. Alpers, Craig A. Stricker
Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone
The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using f
Authors
P.A.M. Bachand, S. Bachand, Jacob A. Fleck, Frank E. Anderson, Lisamarie Windham-Myers
Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter
Monomethyl mercury (MeHg) is a potent neurotoxin that threatens ecosystem viability and human health. In aquatic systems, the photolytic degradation of MeHg (photodemethylation) is an important component of the MeHg cycle. Dissolved organic matter (DOM) is also affected by exposure to solar radiation (light exposure) leading to changes in DOM composition that can affect its role in overall mercury
Authors
Jacob A. Fleck, Gary W. Gill, Brian A. Bergamaschi, Tamara E.C. Kraus, Bryan D. Downing, Charles N. Alpers
Mercury cycling in agricultural and managed wetlands, Yolo Bypass, California: Spatial and seasonal variations in water quality
The seasonal and spatial variability of water quality, including mercury species, was evaluated in agricultural and managed, non-agricultural wetlands in the Yolo Bypass Wildlife Area, an area managed for multiple beneficial uses including bird habitat and rice farming. The study was conducted during an 11-month period (June 2007 to April 2008) that included a summer growing season and flooded con
Authors
Charles N. Alpers, Jacob A. Fleck, Mark C. Marvin-DiPasquale, Craig A. Stricker, Mark Stephenson, Howard E. Taylor
Mercury cycling in agricultural and managed wetlands: a synthesis of methylmercury production, hydrologic export, and bioaccumulation from an integrated field study
With seasonal wetting and drying, and high biological productivity, agricultural wetlands (rice paddies) may enhance the conversion of inorganic mercury (Hg(II)) to methylmercury (MeHg), the more toxic, organic form that biomagnifies through food webs. Yet, the net balance of MeHg sources and sinks in seasonal wetland environments is poorly understood because it requires an annual, integrated asse
Authors
Lisamarie Windham-Myers, Jacob A. Fleck, Joshua T. Ackerman, Mark C. Marvin-DiPasquale, Craig A. Stricker, Wesley A. Heim, Philip A.M. Bachand, Collin A. Eagles-Smith, Gary Gill, Mark Stephenson, Charles N. Alpers
Methylmercury production in and export from agricultural wetlands in California, USA: the need to account for physical transport processes into and out of the root zone
Concentration and mass balance analyses were used to quantify methylmercury (MeHg) loads from conventional (white) rice, wild rice, and fallowed fields in northern California's Yolo Bypass. These analyses were standardized against chloride to distinguish transport pathways and net ecosystem production (NEP). During summer, chloride loads were both exported with surface water and moved into the roo
Authors
Philip A.M. Bachand, Sandra M. Bachand, Jacob A. Fleck, Charles N. Alpers, Mark Stephenson, Lisamarie Windham-Myers
Mercury cycling in agricultural and managed wetlands of California: seasonal influences of vegetation on mercury methylation, storage, and transport
Plants are a dominant biologic and physical component of many wetland capable of influencing the internal pools and fluxes of methylmercury (MeHg). To investigate their role with respect to the latter, we examined the changing seasonal roles of vegetation biomass and Hg, C and N composition from May 2007-February 2008 in 3 types of agricultural wetlands (domesticated or white rice, wild rice, and
Authors
Lisamarie Windham-Myers, Mark C. Marvin-DiPasquale, Evangelos Kakouros, Jennifer L. Agee, Le H. Kieu, Craig A. Stricker, Jacob A. Fleck, Joshua T. Ackerman
Science and Products
Filter Total Items: 15
Data from the development and testing of a multiparameter standard solution for fluorescent dissolved organic matter (fDOM) and algal fluorescence (fChl)
Optical sensors measuring fluorescent dissolved organic matter (fDOM) are increasingly being used in water quality studies because they provide proxy measurements for dissolved organic matter concentrations (DOC). Similarly, chlorophyll-a (chl-a) fluorescence sensors have gained popularity as a means to measure phytoplankton concentration, biomass, and even primary productivity using various appro
Surface-Water Geochemistry of Mercury, Methylmercury, Nutrients, and other Constituents in Clear Lake, Lake County, California, July 2019
Clear Lake is a 180 km2 freshwater lake located in the California Coast Range, approximately 120 km northwest of Sacramento. The lake supports a wide variety of fish and bird species and is a very popular sport-fishing destination. However, fish consumption advisories associated with mercury (Hg) contamination exist for several popular recreational species. The lake is comprised of three main regi
Geochemistry of shallow sediment including mercury, methylmercury and other constituents in the Cache Creek Settling Basin, Yolo County, California, 2010-16
The Cache Creek Settling Basin (CCSB) is a 13.3 km2 leveed basin located at the terminal drainage of the Cache Creek watershed, immediately NE of the town of Woodland (Yolo County), California and approximately 18 km NW of Sacramento, California. The basin was constructed by the U.S. Army Corps of Engineers (completed in 1937 and modified in 1993) for the purpose of trapping suspended sediment tra
Filter Total Items: 36
Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation
Advances in spectroscopic techniques have led to an increase in the use of optical properties (absorbance and fluorescence) to assess dissolved organic matter (DOM) composition and infer sources and processing. However, little information is available to assess the impact of biological and photolytic processing on the optical properties of original DOM source materials. We measured changes in comm
Authors
Angela Hansen, Tamara E. C. Kraus, Brian Pellerin, Jacob Fleck, Bryan D. Downing, Brian A. Bergamaschi
Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada
Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western United States (US) and Canada, a region defined by e
Authors
Collin A. Eagles-Smith, Joshua T. Ackerman, James J. Willacker, Michael T. Tate, Michelle A. Lutz, Jacob Fleck, A. Robin Stewart, James G. Wiener, David C. Evers, Jesse M. Lepak, Jay A. Davis, Colleen Flanagan Pritz
Mercury, monomethyl mercury, and dissolved organic carbon concentrations in surface water entering and exiting constructed wetlands treated with metal-based coagulants, Twitchell Island, California
Coagulation with metal-based salts is a practice commonly employed by drinking-water utilities to decrease particle and dissolved organic carbon concentrations in water. In addition to decreasing dissolved organic carbon concentrations, the effectiveness of iron- and aluminum-based coagulants for decreasing dissolved concentrations both of inorganic and monomethyl mercury in water was demonstrated
Authors
Elizabeth B. Stumpner, Tamara E.C. Kraus, Jacob A. Fleck, Angela M. Hansen, Sandra M. Bachand, William R. Horwath, John F. DeWild, David P. Krabbenhoft, Philip A.M. Bachand
Experimental dosing of wetlands with coagulants removes mercury from surface water and decreases mercury bioaccumulation in fish
Mercury pollution is widespread globally, and strategies for managing mercury contamination in aquatic environments are necessary. We tested whether coagulation with metal-based salts could remove mercury from wetland surface waters and decrease mercury bioaccumulation in fish. In a complete randomized block design, we constructed nine experimental wetlands in California’s Sacramento–San Joaquin D
Authors
Joshua T. Ackerman, Tamara E.C. Kraus, Jacob A. Fleck, David P. Krabbenhoft, William R. Horwarth, Sandra M. Bachand, Mark P. Herzog, C. Alex Hartman, Philip A.M. Bachand
Wetland management and rice farming strategies to decrease methylmercury bioaccumulation and loads from the Cosumnes River Preserve, California
We evaluated mercury (Hg) concentrations in caged fish (deployed for 30 days) and water from agricultural wetland (rice fields), managed wetland, slough, and river habitats in the Cosumnes River Preserve, California. We also implemented experimental hydrological regimes on managed wetlands and post-harvest rice straw management techniques on rice fields in order to evaluate potential Best Manageme
Authors
Collin A. Eagles-Smith, Joshua T. Ackerman, Jacob Fleck, Lisamarie Windham-Myers, Harry McQuillen, Wes Heim
Methylmercury production in sediment from agricultural and non-agricultural wetlands in the Yolo Bypass, California, USA
As part of a larger study of mercury (Hg) biogeochemistry and bioaccumulation in agricultural (rice growing) and non-agricultural wetlands in California's Central Valley, USA, seasonal and spatial controls on methylmercury (MeHg) production were examined in surface sediment. Three types of shallowly-flooded agricultural wetlands (white rice, wild rice, and fallow fields) and two types of managed (
Authors
Mark Marvin-DiPasquale, Lisamarie Windham-Myers, Jennifer L. Agee, Evangelos Kakouros, Le H. Kieu, Jacob A. Fleck, Charles N. Alpers, Craig A. Stricker
Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone
The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using f
Authors
P.A.M. Bachand, S. Bachand, Jacob A. Fleck, Frank E. Anderson, Lisamarie Windham-Myers
Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter
Monomethyl mercury (MeHg) is a potent neurotoxin that threatens ecosystem viability and human health. In aquatic systems, the photolytic degradation of MeHg (photodemethylation) is an important component of the MeHg cycle. Dissolved organic matter (DOM) is also affected by exposure to solar radiation (light exposure) leading to changes in DOM composition that can affect its role in overall mercury
Authors
Jacob A. Fleck, Gary W. Gill, Brian A. Bergamaschi, Tamara E.C. Kraus, Bryan D. Downing, Charles N. Alpers
Mercury cycling in agricultural and managed wetlands, Yolo Bypass, California: Spatial and seasonal variations in water quality
The seasonal and spatial variability of water quality, including mercury species, was evaluated in agricultural and managed, non-agricultural wetlands in the Yolo Bypass Wildlife Area, an area managed for multiple beneficial uses including bird habitat and rice farming. The study was conducted during an 11-month period (June 2007 to April 2008) that included a summer growing season and flooded con
Authors
Charles N. Alpers, Jacob A. Fleck, Mark C. Marvin-DiPasquale, Craig A. Stricker, Mark Stephenson, Howard E. Taylor
Mercury cycling in agricultural and managed wetlands: a synthesis of methylmercury production, hydrologic export, and bioaccumulation from an integrated field study
With seasonal wetting and drying, and high biological productivity, agricultural wetlands (rice paddies) may enhance the conversion of inorganic mercury (Hg(II)) to methylmercury (MeHg), the more toxic, organic form that biomagnifies through food webs. Yet, the net balance of MeHg sources and sinks in seasonal wetland environments is poorly understood because it requires an annual, integrated asse
Authors
Lisamarie Windham-Myers, Jacob A. Fleck, Joshua T. Ackerman, Mark C. Marvin-DiPasquale, Craig A. Stricker, Wesley A. Heim, Philip A.M. Bachand, Collin A. Eagles-Smith, Gary Gill, Mark Stephenson, Charles N. Alpers
Methylmercury production in and export from agricultural wetlands in California, USA: the need to account for physical transport processes into and out of the root zone
Concentration and mass balance analyses were used to quantify methylmercury (MeHg) loads from conventional (white) rice, wild rice, and fallowed fields in northern California's Yolo Bypass. These analyses were standardized against chloride to distinguish transport pathways and net ecosystem production (NEP). During summer, chloride loads were both exported with surface water and moved into the roo
Authors
Philip A.M. Bachand, Sandra M. Bachand, Jacob A. Fleck, Charles N. Alpers, Mark Stephenson, Lisamarie Windham-Myers
Mercury cycling in agricultural and managed wetlands of California: seasonal influences of vegetation on mercury methylation, storage, and transport
Plants are a dominant biologic and physical component of many wetland capable of influencing the internal pools and fluxes of methylmercury (MeHg). To investigate their role with respect to the latter, we examined the changing seasonal roles of vegetation biomass and Hg, C and N composition from May 2007-February 2008 in 3 types of agricultural wetlands (domesticated or white rice, wild rice, and
Authors
Lisamarie Windham-Myers, Mark C. Marvin-DiPasquale, Evangelos Kakouros, Jennifer L. Agee, Le H. Kieu, Craig A. Stricker, Jacob A. Fleck, Joshua T. Ackerman