Larry Brown (Former Employee)
Science and Products
Filter Total Items: 121
Occurrence and accumulation of pesticides and organic contaminants in river sediment, water and clam tissues from the San Joaquin River and tributaries, California
A study was conducted in 1992 to assess the effects of anthropogenic activities and land use on the water quality of the San Joaquin River and its major tributaries. This study focused on pesticides and organic contaminants, looking at distributions of contaminants in water, bed and suspended sediment, and the bivalve Corbicula fluminea. Results indicated that this river system is affected by agri
Authors
W. E. Pereira, Joseph L. Domagalski, F. D. Hostettler, L. R. Brown, J. B. Rapp
Effect of predation by Sacramento squawfish (Ptychocheilus grandis) on habitat choice of California roach (Lavinia symmetricus) and rainbow trout (Oncorhynchus mykiss) in artificial streams
We studied the effects of predatory Sacramento squawfish (Ptychocheilus grandis) on habitat choice of juvenile California roach (Lavinia symmetricus), adult roach, and juvenile rainbow trout (Oncorhynchus mykiss) in artificial streams. In single-prey trials, the proportion of fish found in pool habitat declined in the presence of squawfish for juvenile roach (from 0.55 to 0.00), adult roach (from
Authors
Larry R. Brown, Anne M. D. Brasher
Comparative ecology of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River, California
We documented species' distributions, size structure of populations, abundance in mainstem and tributary streams, habitat use, and diets of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River drainage of California, to determine the processes allowing coexistence of these very similar fishes. We observed prickly sculpins at 43 sites and coastrange sculpins at 34.
Authors
Larry R. Brown, Scott A. Matern, Peter B. Moyle
Historical decline and current status of coho salmon in California
The southernmost populations of coho salmon Oncorhynchus kisutch occur in California where native coho stocks have declined or disappeared from all streams in which they were historically recorded. Coho salmon previously occurred in as many as 582 streams, from the Smith River near the Oregon border to the San Lorenzo River on the central coast. Information on the recent presence or absence of coh
Authors
Larry R. Brown, Peter B. Moyle, Ronald M. Yoshiyama
National Water-Quality Assessment Program: The Sacramento River Basin
In 1991, the U.S. Geological Survey (USGS) began to implement a full-scale National Water-Quality Assessment (NAWQA) program. The long-term goals of the NAWQA program are to describe the status of and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to identify the major natural and human factors that affect the quality of those resource
Authors
Joseph L. Domagalski, Larry R. Brown
Implications of morphological variation among populations of California roach Lavinia symmetricus (Cyprinidae) for conservation policy
The California roach Lavinia symmetricus is a small cyprinid native to Central California. Populations of roach are presently isolated from one another due to degradation of stream habitats between them. We examined eight populations, each from a tributary system of the San Joaquin River, to determine if morphological differences existed among them. These tributaries are now isolated from one anot
Authors
Larry R. Brown, Peter B. Moyle, William A. Bennett, Brian D. Quelvog
Seasonal changes in microhabitat selection by rainbow trout in a small stream
Shifts in microhabitat selection by rainbow trout Oncorhynchus mykiss were related to seasonal and ontogenetic factors in a small stream characterized by short riffles, small pools, and boulder substrate. Resource availability did not differ significantly between summer and November sampling dates for most variables related to water velocity, substrate, and cover, although depths were greater and
Authors
Donald M. Baltz, Bruce C. Vondracek, Larry R. Brown, Peter B. Moyle
Brunhes chron excursion/polarity episode recorded during the late pleistocene, Albuquerque Volcanoes, New Mexico, USA
All basaltic lava flows of the Albuquerque Volcanoes (lat.: 35.2°N, long.: 253.2°E), Albuquerque-Belen Basin, New Mexico, record a short excursion/polarity episode. K-Ar isotopic age determinations (weighted average: 155 ± 47 ka) and evaluation of soil profiles on flow surfaces suggest the late Pleistocene (circa between 250 and 80 ka) as the time of extrusion. Results from 63 sites in a minimum o
Authors
J. W. Geissman, L. Brown, B.D. Turrin, L. D. McFadden, S. S. Harlan
Spatial, seasonal and diel distribution of fishes in a California reservoir dominated by native fishes
During 21 months of sampling with various techniques, we captured 24 species of fish in Britton Reservoir. Nine species comprised over 96% of the number of fish captured and approximately 88% of the biomass. Five native non-game species accounted for over 77% of the catches.The native non-game fishes have maintained large populations in the reservoir despite continued introductions of non-native s
Authors
Bruce C. Vondracek, Donald M. Baltz, Larry R. Brown, Peter B. Moyle
10Be distribution in soils from Merced River terraces, California
The distribution and residence time of cosmogenic 10Be in clay-rich soil horizons is fundamental to understanding and modelling the migration of 10Be on terrestrial sediments and in groundwater solutions. We have analyzed seven profiles of clay-rich soils developed from terrace sediments of the Merced River, California. The terraces and soils of increasing age are used to compare the 10Be inventor
Authors
M.J. Pavich, L. Brown, J. Harden, J. Klein, R. Middleton
Detection of erosion events using 10Be profiles: example of the impact of agriculture on soil erosion in the Chesapeake Bay area (U.S.A.)
10Be concentration, total carbon and grain-size were measured in cores collected in undisturbed estuarine sediments of three tributaries of the Chesapeake Bay. These cores were previously studied by Davis [1] and Brush [2,3] for pollen content, age and sedimentation rate. In this work, we compare the results obtained for these various analyses.In the cores, we observed two increases in10Be concent
Authors
J. N. Valette-Silver, L. Brown, M. Pavich, J. Klein, R. Middleton
10Be accumulation in a soil chronosequence
We have measured the concentration of the cosmogenic isotope10Be in soil samples from various horizons at six sites, including three independently dated Rappahannock River terraces and a previously undated Piedmont soil to which we have assigned an age. All of the incident10Be can be accounted for in one of these soils and a second is within a factor of two. In three soils, whose concentrations va
Authors
M.J. Pavich, L. Brown, J. Klein, R. Middleton
Science and Products
Filter Total Items: 121
Occurrence and accumulation of pesticides and organic contaminants in river sediment, water and clam tissues from the San Joaquin River and tributaries, California
A study was conducted in 1992 to assess the effects of anthropogenic activities and land use on the water quality of the San Joaquin River and its major tributaries. This study focused on pesticides and organic contaminants, looking at distributions of contaminants in water, bed and suspended sediment, and the bivalve Corbicula fluminea. Results indicated that this river system is affected by agri
Authors
W. E. Pereira, Joseph L. Domagalski, F. D. Hostettler, L. R. Brown, J. B. Rapp
Effect of predation by Sacramento squawfish (Ptychocheilus grandis) on habitat choice of California roach (Lavinia symmetricus) and rainbow trout (Oncorhynchus mykiss) in artificial streams
We studied the effects of predatory Sacramento squawfish (Ptychocheilus grandis) on habitat choice of juvenile California roach (Lavinia symmetricus), adult roach, and juvenile rainbow trout (Oncorhynchus mykiss) in artificial streams. In single-prey trials, the proportion of fish found in pool habitat declined in the presence of squawfish for juvenile roach (from 0.55 to 0.00), adult roach (from
Authors
Larry R. Brown, Anne M. D. Brasher
Comparative ecology of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River, California
We documented species' distributions, size structure of populations, abundance in mainstem and tributary streams, habitat use, and diets of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River drainage of California, to determine the processes allowing coexistence of these very similar fishes. We observed prickly sculpins at 43 sites and coastrange sculpins at 34.
Authors
Larry R. Brown, Scott A. Matern, Peter B. Moyle
Historical decline and current status of coho salmon in California
The southernmost populations of coho salmon Oncorhynchus kisutch occur in California where native coho stocks have declined or disappeared from all streams in which they were historically recorded. Coho salmon previously occurred in as many as 582 streams, from the Smith River near the Oregon border to the San Lorenzo River on the central coast. Information on the recent presence or absence of coh
Authors
Larry R. Brown, Peter B. Moyle, Ronald M. Yoshiyama
National Water-Quality Assessment Program: The Sacramento River Basin
In 1991, the U.S. Geological Survey (USGS) began to implement a full-scale National Water-Quality Assessment (NAWQA) program. The long-term goals of the NAWQA program are to describe the status of and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to identify the major natural and human factors that affect the quality of those resource
Authors
Joseph L. Domagalski, Larry R. Brown
Implications of morphological variation among populations of California roach Lavinia symmetricus (Cyprinidae) for conservation policy
The California roach Lavinia symmetricus is a small cyprinid native to Central California. Populations of roach are presently isolated from one another due to degradation of stream habitats between them. We examined eight populations, each from a tributary system of the San Joaquin River, to determine if morphological differences existed among them. These tributaries are now isolated from one anot
Authors
Larry R. Brown, Peter B. Moyle, William A. Bennett, Brian D. Quelvog
Seasonal changes in microhabitat selection by rainbow trout in a small stream
Shifts in microhabitat selection by rainbow trout Oncorhynchus mykiss were related to seasonal and ontogenetic factors in a small stream characterized by short riffles, small pools, and boulder substrate. Resource availability did not differ significantly between summer and November sampling dates for most variables related to water velocity, substrate, and cover, although depths were greater and
Authors
Donald M. Baltz, Bruce C. Vondracek, Larry R. Brown, Peter B. Moyle
Brunhes chron excursion/polarity episode recorded during the late pleistocene, Albuquerque Volcanoes, New Mexico, USA
All basaltic lava flows of the Albuquerque Volcanoes (lat.: 35.2°N, long.: 253.2°E), Albuquerque-Belen Basin, New Mexico, record a short excursion/polarity episode. K-Ar isotopic age determinations (weighted average: 155 ± 47 ka) and evaluation of soil profiles on flow surfaces suggest the late Pleistocene (circa between 250 and 80 ka) as the time of extrusion. Results from 63 sites in a minimum o
Authors
J. W. Geissman, L. Brown, B.D. Turrin, L. D. McFadden, S. S. Harlan
Spatial, seasonal and diel distribution of fishes in a California reservoir dominated by native fishes
During 21 months of sampling with various techniques, we captured 24 species of fish in Britton Reservoir. Nine species comprised over 96% of the number of fish captured and approximately 88% of the biomass. Five native non-game species accounted for over 77% of the catches.The native non-game fishes have maintained large populations in the reservoir despite continued introductions of non-native s
Authors
Bruce C. Vondracek, Donald M. Baltz, Larry R. Brown, Peter B. Moyle
10Be distribution in soils from Merced River terraces, California
The distribution and residence time of cosmogenic 10Be in clay-rich soil horizons is fundamental to understanding and modelling the migration of 10Be on terrestrial sediments and in groundwater solutions. We have analyzed seven profiles of clay-rich soils developed from terrace sediments of the Merced River, California. The terraces and soils of increasing age are used to compare the 10Be inventor
Authors
M.J. Pavich, L. Brown, J. Harden, J. Klein, R. Middleton
Detection of erosion events using 10Be profiles: example of the impact of agriculture on soil erosion in the Chesapeake Bay area (U.S.A.)
10Be concentration, total carbon and grain-size were measured in cores collected in undisturbed estuarine sediments of three tributaries of the Chesapeake Bay. These cores were previously studied by Davis [1] and Brush [2,3] for pollen content, age and sedimentation rate. In this work, we compare the results obtained for these various analyses.In the cores, we observed two increases in10Be concent
Authors
J. N. Valette-Silver, L. Brown, M. Pavich, J. Klein, R. Middleton
10Be accumulation in a soil chronosequence
We have measured the concentration of the cosmogenic isotope10Be in soil samples from various horizons at six sites, including three independently dated Rappahannock River terraces and a previously undated Piedmont soil to which we have assigned an age. All of the incident10Be can be accounted for in one of these soils and a second is within a factor of two. In three soils, whose concentrations va
Authors
M.J. Pavich, L. Brown, J. Klein, R. Middleton
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government