James Cloern
James (Jim) Cloern is a senior scientist emeritus at the U.S. Geological Survey's Water Resources Mission Area in Menlo Park, California.
James (Jim) Cloern is a senior scientist emeritus at the U.S. Geological Survey in Menlo Park, California. His research over four decades addresses comparative ecology and biogeochemistry of estuaries to understand how they respond as ecosystems to climatic-hydrologic variability and human disturbance. His team investigation of San Francisco Bay included studies of primary production, nutrient cycling, algal and zooplankton community dynamics, ecosystem metabolism and food web dynamics, disturbance by introduced species, ecosystem restoration, and past and projected future responses to a changing climate. His career achievements have been recognized with selection as Fellows of the American Geophysical Union (AGU) and Association for the Sciences of Limnology and Oceanography (ASLO), and as recipient of the Woods Hole Oceanographic Institution B.H. Ketchum Award, Delta Science Program Brown-Nichols Achievement Award, ASLO Ruth Patrick Award, Coastal and Estuarine Research Federation Odum Lifetime Achievement Award, and Department of Interior's Distinguished Service Award. He is currently an Adjunct Senior Fellow at the Public Policy Institute of California, a member of the Delta Stewardship Council's Independent Science Board, and editor-in-chief of Limnology and Oceanography Letters.
Science and Products
Notes on a Mesodinium rubrum red tide in San Francisco Bay (California, USA)
San Francisco Bay/delta regional monitoring program plankton and water quality pilot study, 1993, in 1993 Annual Report, San Francisco Estuary Regional Monitoring Program for Trace Substances: San Francisco Estuary Institute
Coupled effects of vertical mixing and benthic grazing on phytoplankton populations in shallow, turbid estuaries
1993 Annual Report: San Francisco estuary regional monitoring program for trace substances
Organic carbon sources and sinks in San Francisco Bay: variability induced by river flow
Annual variations in river flow and primary production in the south San Francisco Bay estuary (USA)
Plankton studies in San Francisco Bay; IX, Chlorophyll distributions and hydrographic properties of South San Francisco Bay, 1984-86
Phytoplankton growth rates in a light-limited environment, San Francisco Bay
Big Soda Lake (Nevada). 4. Vertical fluxes of particulate matter: Seasonality and variations across the chemocline
Big Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass
Modeling of estuarne chlorophyll a from an airborne scanner
The modification of an estuary
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Notes on a Mesodinium rubrum red tide in San Francisco Bay (California, USA)
Discrete red patches of water were observed in South San Francisco Bay (USA) on 30 April 1993, and examination of live samples showed that this red tide was caused by surface accumulations of the pigmented ciliate Mesodinium rubrum . Vertical profiles showed strong salinity and temperature stratification in the upper 5 m, peak chlorophyll fluorescence in the upper meter, and differences in the smaAuthorsJames E. Cloern, Brian E. Cole, Stephen W. HagerSan Francisco Bay/delta regional monitoring program plankton and water quality pilot study, 1993, in 1993 Annual Report, San Francisco Estuary Regional Monitoring Program for Trace Substances: San Francisco Estuary Institute
The pilot program described here is motivated by a fundamental principle of the Regional Monitoring Strategy, namely “...the development of data that will provide information on status and trends in the Estuary.” As pointed out in the Strategy, knowledge of status and trends serves two primary purposes: (1) to become aware of or anticipate deleterious conditions in the Estuary, and (2) to assess tAuthorsAlan D. Jassby, James E. Cloern, J. Caffrey, B. Cole, J. RudekCoupled effects of vertical mixing and benthic grazing on phytoplankton populations in shallow, turbid estuaries
Coastal ocean waters tend to have very different patterns of phytoplankton biomass variability from the open ocean, and the connections between physical variability and phytoplankton bloom dynamics are less well established for these shallow systems. Predictions of biological responses to physical variability in these environments is inherently difficult because the recurrent seasonal patterns ofAuthorsJeffrey R. Koseff, Jacqueline K. Holen, Stephen G. Monismith, James E. Cloern1993 Annual Report: San Francisco estuary regional monitoring program for trace substances
This first annual report of the San Francisco Estuary Regional Monitoring Program contains the results of monitoring measurements made in 1993. Measurements of conventional water quality parameters and trace contaminant concentrations were made at 16 stations throughout the Estuary three times during the year: the wet period (March), during declining Delta outflow (May), and during the dry periodAuthorsB. Thompson, Jessica Lacy, Dane Hardin, Tom Grovhaug, K. Taberski, Alan D. Jassby, James E. Cloern, J. Caffrey, B. Cole, David H. SchoellhamerOrganic carbon sources and sinks in San Francisco Bay: variability induced by river flow
Sources and sinks of organic carbon for San Francisco Bay (California, USA) were estimated for 1980. Sources for the southern reach were dominated by phytoplankton and benthic microalgal production. River loading of organic matter was an additional important factor in the northern reach. Tidal marsh export and point sources played a secondary role. Autochthonous production in San Francisco Bay apAuthorsAlan D. Jassby, T.M. Powell, James E. CloernAnnual variations in river flow and primary production in the south San Francisco Bay estuary (USA)
No abstract available.AuthorsJames E. CloernPlankton studies in San Francisco Bay; IX, Chlorophyll distributions and hydrographic properties of South San Francisco Bay, 1984-86
This report summarizes the distribution of phytoplankton biomass and selected hydrographic properties in South San Francisco Bay during 1984- 1986. There were a total of 67 cruises during the three-year period with the most frequent sampling occurring during the spring. Parameters measured were chlorophyll a, phaeopigments, in-vivo fluorescence, turbidity, salinity, and temperature.AuthorsAndrea A. Alpine, Sally M. Wienke, James E. Cloern, Brian E. ColePhytoplankton growth rates in a light-limited environment, San Francisco Bay
Phytoplankton cells reside in a turbulent medium partitioned into an upper photic zone that sustains photosynthesis, and a lower aphotic zone that does not. In estuaries, vertical mixing rates between these 2 zones can be rapid (< 1 generation time) because of tidal stirring and because the mixing depth is generally shallow. Moreover, the photic depth is characteristically shallow in estuaries becAuthorsAndrea E. Alpine, James E. CloernBig Soda Lake (Nevada). 4. Vertical fluxes of particulate matter: Seasonality and variations across the chemocline
Vertical fluxes of particulate organic matter were measured with sediment traps above and below the chemocline of Big Soda Lake to define the seasonality of sinking losses from the mixolimnion and determine the effectiveness of the chemocline (pycnocline) as a barrier to the sinking of biogenic particles. Seasonality of sedimentation rates reflected seasonal changes in the community of autotrophs.AuthorsJames E. Cloern, Brian E. Cole, Sally M. WienkeBig Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass
Bacterial activities and abundance were measured seasonally in the water column of meromictic Big Soda Lake which is divided into three chemically distinct zones: aerobic mixolimnion, anaerobic mixolimnion, and anaerobic monimolimnion. Bacterial abundance ranged between 5 and 52 x 106 cells ml−1, with highest biomass at the interfaces between these zones: 2–4 mg C liter−1 in the photosynthetic bacAuthorsJon P. Zehr, Ronald W. Harvey, Ronald S. Oremland, James E. Cloern, Leah H. George, Judith L. LaneModeling of estuarne chlorophyll a from an airborne scanner
Near simultaneous collection of 34 surface water samples and airborne multispectral scanner data provided input for regression models developed to predict surface concentrations of estuarine chlorophyll a. Two wavelength ratios were employed in model development. The ratios werechosen to capitalize on the spectral characteristics of chlorophyll a, while minimizing atmospheric influences. Models wAuthorsSiamak Khorram, Glenn P. Catts, James E. Cloern, Allen W. KnightThe modification of an estuary
The San Francisco Bay estuary has been rapidly modified by human activity. Diking and filling of most of its wetlands have eliminated habitats for fish and waterfowl; the introduction of exotic species has transformed the composition of its aquatic communities; reduction of freshwater inflow by more than half has changed the dynamics of its plant and animal communities; and wastes have contaminateAuthorsF.H. Nichols, James E. Cloern, Samuel N. Luoma, D.H. Peterson