Brent Topping
Brent is the Quality Management System (QMS) Manager for the Southwest Region. He, and the USGS QMS Team, lead USGS laboratories through implementation of a new Bureau-wide QMS. Brent works closely with Southwest Region laboratories and their staff on the implementation of 10 Core Elements, including documentation, procedures, methods, quality controls, sample management and quality assessments.
Science and Products
Filter Total Items: 24
Mercury speciation in piscivorous fish from mining-impacted reservoirs
Guadalupe Reservoir (GUA), California, and Lahontan Reservoir (LAH), Nevada, U.S. are both affected either directly or indirectly by the legacy of gold and silver mining in the Sierra Nevada during the nineteenth century. Analysis of total mercury in fish from these lentic systems consistently indicate elevated concentrations (>1 μg·g-1 wet weight; hereinafter, all concentrations are reported as w
Authors
James S. Kuwabara, Yuji Arai, Brent R. Topping, I.J. Pickering, G.N. George
Free zinc ion and dissolved orthophosphate effects on phytoplankton from Coeur d'Alene Lake, Idaho
Coeur d'Alene Lake in northern Idaho is fed by two major rivers: the Coeur d'Alene River from the east and the St. Joe River from the south, with the Spokane River as its outlet to the north. This phosphorus-limited lake has been subjected to decades of mining (primarily for zinc and silver) and other anthropogenic inputs. A 32 full-factorial experimental design was used to examine the interactiv
Authors
James S. Kuwabara, Brent R. Topping, Paul F. Woods, James L. Carter
Interactive effects of dissolved zinc and orthophosphate on phytoplankton from Coeur d'Alene Lake, Idaho
Within the longitudinal chemical-concentration gradient in Coeur d'Alene Lake, generated by inputs from the St. Joe and Coeur d'Alene Rivers, two dominant algal species, Chlorella minutissima and Asterionella formosa, were isolated and cultured in chemically defined media to examine growth response to a range of dissolved orthophosphate concentrations and zinc-ion activities representative of the
Authors
James S. Kuwabara, Brent R. Topping, Paul F. Woods, James L. Carter, Stephen W. Hager
Mercury accumulation by lower trophic-level organisms in lentic systems within the Guadalupe River watershed, California
The water columns of four reservoirs (Almaden, Calero, Guadalupe and Lexington Reservoirs) and an abandoned quarry pit filled by Alamitos Creek drainage for recreational purposes (Lake Almaden) were sampled on September 14 and 15, 2004 to provide the first measurements of mercury accumulation by phytoplankton and zooplankton in lentic systems (bodies of standing water, as in lakes and reservoirs)
Authors
James S. Kuwabara, Brent R. Topping, Gerald E. Moon, Peter Husby, Andrew Lincoff, James L. Carter, Marie-Noële Croteau
Sediment remobilization of Mercury in South San Francisco Bay, California
No abstract available.
Authors
Brent R. Topping, James S. Kuwabara, Mark C. Marvin-DisPasquale, Jennifer L. Agee, Le H. Kieu, John R. Flanders, Francis Parcheso, Stephen W. Hager, Cary B. Lopez, David P. Krabbenhoft
Stable metal isotopes reveal copper accumulation and loss dynamics in the freshwater bivalve Corbucula
Characterization of uptake and loss dynamics is critical to understanding risks associated with contaminant exposure in aquatic animals. Dynamics are especially important in addressing questions such as why coexisting species in nature accumulate different levels of a contaminant. Here we manipulated copper (Cu) stable isotopic ratios (as an alternative to radioisotopes) to describe for the first
Authors
M.-N. Croteau, S. N. Luoma, B.R. Topping, C.B. Lopez
Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California
No abstract available.
Authors
James S. Kuwabara, Charles N. Alpers, Mark Marvin-DiPasquale, Brent R. Topping, James L. Carter, A. Robin Stewart, Steven V. Fend, Francis Parcheso, Gerald E. Moon, David P. Krabbenhoft
Dissolved nickel and benthic flux in South San Francisco Bay: A potential for natural sources to dominate
No abstract available.
Authors
B.R. Topping, J.S. Kuwabara
Importance of Sediment-Water Interactions in Coeur d'Alene Lake, Idaho, USA: Management Implications
A field study at Coeur d'Alene Lake, Idaho, USA, was conducted between October 1998 and August 2001 to examine the potential importance of sediment-water interactions on contaminant transport and to provide the first direct measurements of the benthic flux of dissolved solutes of environmental concern in this lake. Because of potential ecological effects, dissolved zinc and orthophosphate were the
Authors
J.S. Kuwabara, J.L. Carter, B.R. Topping, S.V. Fend, P. F. Woods, W.M. Berelson, Laurie S. Balistrieri
Flux of dissolved forms of mercury across the sediment-water interface in Lahontan Reservoir, Nevada
No abstract available.
Authors
James S. Kuwabara, Mark Marvin-DiPasquale, Wayne Praskins, Earl Byron, Brent R. Topping, James L. Carter, Steven V. Fend, Francis Parcheso, David P. Krabbenhoft, Mae S. Gustin
Benthic flux of dissolved nickel into the water column of south San Francisco Bay
Field and laboratory studies were conducted between April, 1998 and May, 1999 to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) nickel between the bottom sediment and water column at three sites in the southern component of San Francisco Bay (South Bay), California. Dissolved nickel and predominant ligands (represented by dissolved organic carbon, and
Authors
B.R. Topping, J.S. Kuwabara, Francis Parcheso, S.W. Hager, A.J. Arnsberg, Fred Murphy
Benthic flux of metals and nutrients into the water column of Lake Coeur d'Alene, Idaho: Report of an August, 1999, pilot study
A field study was conducted between August 16-27, 1999, to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) solutes between the bottom sediment and water column at two sites in Lake Coeur d'Alene, Idaho. Trace metals (namely, cadmium, copper, manganese, mercury species, and zinc) and nutrients (namely, ammonia, nitrate plus nitrite, oxygen, orthophosphat
Authors
James S. Kuwabara, William M. Berelson, Laurie S. Balistrieri, Paul F. Woods, Brent R. Topping, Douglas J. Steding, David P. Krabbenhoft
Science and Products
Filter Total Items: 24
Mercury speciation in piscivorous fish from mining-impacted reservoirs
Guadalupe Reservoir (GUA), California, and Lahontan Reservoir (LAH), Nevada, U.S. are both affected either directly or indirectly by the legacy of gold and silver mining in the Sierra Nevada during the nineteenth century. Analysis of total mercury in fish from these lentic systems consistently indicate elevated concentrations (>1 μg·g-1 wet weight; hereinafter, all concentrations are reported as w
Authors
James S. Kuwabara, Yuji Arai, Brent R. Topping, I.J. Pickering, G.N. George
Free zinc ion and dissolved orthophosphate effects on phytoplankton from Coeur d'Alene Lake, Idaho
Coeur d'Alene Lake in northern Idaho is fed by two major rivers: the Coeur d'Alene River from the east and the St. Joe River from the south, with the Spokane River as its outlet to the north. This phosphorus-limited lake has been subjected to decades of mining (primarily for zinc and silver) and other anthropogenic inputs. A 32 full-factorial experimental design was used to examine the interactiv
Authors
James S. Kuwabara, Brent R. Topping, Paul F. Woods, James L. Carter
Interactive effects of dissolved zinc and orthophosphate on phytoplankton from Coeur d'Alene Lake, Idaho
Within the longitudinal chemical-concentration gradient in Coeur d'Alene Lake, generated by inputs from the St. Joe and Coeur d'Alene Rivers, two dominant algal species, Chlorella minutissima and Asterionella formosa, were isolated and cultured in chemically defined media to examine growth response to a range of dissolved orthophosphate concentrations and zinc-ion activities representative of the
Authors
James S. Kuwabara, Brent R. Topping, Paul F. Woods, James L. Carter, Stephen W. Hager
Mercury accumulation by lower trophic-level organisms in lentic systems within the Guadalupe River watershed, California
The water columns of four reservoirs (Almaden, Calero, Guadalupe and Lexington Reservoirs) and an abandoned quarry pit filled by Alamitos Creek drainage for recreational purposes (Lake Almaden) were sampled on September 14 and 15, 2004 to provide the first measurements of mercury accumulation by phytoplankton and zooplankton in lentic systems (bodies of standing water, as in lakes and reservoirs)
Authors
James S. Kuwabara, Brent R. Topping, Gerald E. Moon, Peter Husby, Andrew Lincoff, James L. Carter, Marie-Noële Croteau
Sediment remobilization of Mercury in South San Francisco Bay, California
No abstract available.
Authors
Brent R. Topping, James S. Kuwabara, Mark C. Marvin-DisPasquale, Jennifer L. Agee, Le H. Kieu, John R. Flanders, Francis Parcheso, Stephen W. Hager, Cary B. Lopez, David P. Krabbenhoft
Stable metal isotopes reveal copper accumulation and loss dynamics in the freshwater bivalve Corbucula
Characterization of uptake and loss dynamics is critical to understanding risks associated with contaminant exposure in aquatic animals. Dynamics are especially important in addressing questions such as why coexisting species in nature accumulate different levels of a contaminant. Here we manipulated copper (Cu) stable isotopic ratios (as an alternative to radioisotopes) to describe for the first
Authors
M.-N. Croteau, S. N. Luoma, B.R. Topping, C.B. Lopez
Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California
No abstract available.
Authors
James S. Kuwabara, Charles N. Alpers, Mark Marvin-DiPasquale, Brent R. Topping, James L. Carter, A. Robin Stewart, Steven V. Fend, Francis Parcheso, Gerald E. Moon, David P. Krabbenhoft
Dissolved nickel and benthic flux in South San Francisco Bay: A potential for natural sources to dominate
No abstract available.
Authors
B.R. Topping, J.S. Kuwabara
Importance of Sediment-Water Interactions in Coeur d'Alene Lake, Idaho, USA: Management Implications
A field study at Coeur d'Alene Lake, Idaho, USA, was conducted between October 1998 and August 2001 to examine the potential importance of sediment-water interactions on contaminant transport and to provide the first direct measurements of the benthic flux of dissolved solutes of environmental concern in this lake. Because of potential ecological effects, dissolved zinc and orthophosphate were the
Authors
J.S. Kuwabara, J.L. Carter, B.R. Topping, S.V. Fend, P. F. Woods, W.M. Berelson, Laurie S. Balistrieri
Flux of dissolved forms of mercury across the sediment-water interface in Lahontan Reservoir, Nevada
No abstract available.
Authors
James S. Kuwabara, Mark Marvin-DiPasquale, Wayne Praskins, Earl Byron, Brent R. Topping, James L. Carter, Steven V. Fend, Francis Parcheso, David P. Krabbenhoft, Mae S. Gustin
Benthic flux of dissolved nickel into the water column of south San Francisco Bay
Field and laboratory studies were conducted between April, 1998 and May, 1999 to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) nickel between the bottom sediment and water column at three sites in the southern component of San Francisco Bay (South Bay), California. Dissolved nickel and predominant ligands (represented by dissolved organic carbon, and
Authors
B.R. Topping, J.S. Kuwabara, Francis Parcheso, S.W. Hager, A.J. Arnsberg, Fred Murphy
Benthic flux of metals and nutrients into the water column of Lake Coeur d'Alene, Idaho: Report of an August, 1999, pilot study
A field study was conducted between August 16-27, 1999, to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) solutes between the bottom sediment and water column at two sites in Lake Coeur d'Alene, Idaho. Trace metals (namely, cadmium, copper, manganese, mercury species, and zinc) and nutrients (namely, ammonia, nitrate plus nitrite, oxygen, orthophosphat
Authors
James S. Kuwabara, William M. Berelson, Laurie S. Balistrieri, Paul F. Woods, Brent R. Topping, Douglas J. Steding, David P. Krabbenhoft