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
Lessons from monitoring water quality in San Francisco Bay
Phytoplankton fuels Delta food web
Effects of spatial and temporal variability of turbidity on phytoplankton blooms
Clams as CO2 generators: The Potamocorbula amurensis example in San Francisco Bay
Microphytobenthos potential productivity estimated in three tidal embayments of the San Francisco Bay system
Functional variability of habitats within the Sacramento-San Joaquin Delta: Restoration implications
Annual primary production: Patterns and mechanisms of change in a nutrient-rich tidal ecosystem
Effects of tidal shallowing and deepening on phytoplankton production dynamics: A modeling study
A comment on the use of flushing time, residence time, and age as transport time scales
Studies of the San Francisco Bay, California, estuarine ecosystem--Regional monitoring program results, 1998
Our evolving conceptual model of the coastal eutrophication problem
Primary food resources in the Sacramento-San Joaquin Delta
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Lessons from monitoring water quality in San Francisco Bay
San Francisco Bay is the defining landscape feature of the place we call ‘The Bay Area,’ but most of us only experience the Bay as we view it from an airplane window or drive across one of its bridges. These views from afar suggest that the Bay is static and sterile, but this impression is deceptive. If you are one of the many thousands of students who have experienced the Bay through a school excAuthorsJ. E. Cloern, T.S. Schraga, C.B. Lopez, R. LabiosaPhytoplankton fuels Delta food web
Populations of certain fishes and invertebrates in the Sacramento-San Joaquin Delta have declined in abundance in recent decades and there is evidence that food supply is partly responsible. While many sources of organic matter in the Delta could be supporting fish populations indirectly through the food web (including aquatic vegetation and decaying organic matter from agricultural drainage), a cAuthorsAlan D. Jassby, James E. Cloern, A. B. Muller-SolgerEffects of spatial and temporal variability of turbidity on phytoplankton blooms
A central challenge of coastal ecology is sorting out the interacting spatial and temporal components of environmental variability that combine to drive changes in phytoplankton biomass. For 2 decades, we have combined sustained observation and experimentation in South San Francisco Bay (SSFB) with numerical modeling analyses to search for general principles that define phytoplankton population reAuthorsChristine L. May, Jeffrey R. Koseff, Lisa Lucas, James E. Cloern, David H. SchoellhamerClams as CO2 generators: The Potamocorbula amurensis example in San Francisco Bay
Respiration and calcium carbonate production by the invasive Asian clam, Potamocorbula amurensis, were calculated to assess their importance as CO2 sources in northern San Francisco Bay. Production, calculated using monthly population density and size structure measured at three sites over 7 yr and a shell length/CaCO3 conversion factor, averaged 221(±184)g CaCO3 m−2yr−1. Net calcium carbonate proAuthorsLaurent Chauvaud, Janet K. Thompson, James E. Cloern, Gerard ThouzeauMicrophytobenthos potential productivity estimated in three tidal embayments of the San Francisco Bay system
In this paper we describe a three-step procedure to infer the spatial heterogeneity in microphytobenthos primary productivity at the scale of tidal estuaries and embayments. The first step involves local measurement of the carbon assimilation rate of benthic microalgae to determine the parameters of the photosynthesis-irradiance (P-E) curves (using non-linear optimization methods). In the next steAuthorsJean-Marc Guarini, James E. Cloern, Jody L. Edmunds, Philippe GrosFunctional variability of habitats within the Sacramento-San Joaquin Delta: Restoration implications
We have now entered an era of large-scale attempts to restore ecological functions and biological communities in impaired ecosystems. Our knowledge base of complex ecosystems and interrelated functions is limited, so the outcomes of specific restoration actions are highly uncertain. One approach for exploring that uncertainty and anticipating the range of possible restoration outcomes is comparatiAuthorsL.V. Lucas, J. E. Cloern, J.K. Thompson, N.E. MonsenAnnual primary production: Patterns and mechanisms of change in a nutrient-rich tidal ecosystem
Although nutrient supply often underlies long-term changes in aquatic primary production, other regulatory processes can be important. The Sacramento-San Joaquin River Delta, a complex of tidal waterways forming the landward portion of the San Francisco Estuary, has ample nutrient supplies, enabling us to examine alternate regulatory mechanisms over a 21-yr period. Delta-wide primary productivityAuthorsAlan D. Jassby, James E. Cloern, B.E. ColeEffects of tidal shallowing and deepening on phytoplankton production dynamics: A modeling study
Processes influencing estuarine phytoplankton growth occur over a range of time scales, but many conceptual and numerical models of estuarine phytoplankton production dynamics neglect mechanisms occurring on the shorter (e.g., intratidal) time scales. We used a numerical model to explore the influence of short time-scale variability in phytoplankton sources and sinks on long-term growth in an ideaAuthorsL.V. Lucas, J. E. CloernA comment on the use of flushing time, residence time, and age as transport time scales
Applications of transport time scales are pervasive in biological, hydrologic, and geochemical studies yet these times scales are not consistently defined and applied with rigor in the literature. We compare three transport time scales (flushing time, age, and residence time) commonly used to measure the retention of water or scalar quantities transported with water. We identify the underlying assAuthorsNancy E. Monsen, James E. Cloern, Lisa V. Lucas, Stephen G. MonismithStudies of the San Francisco Bay, California, estuarine ecosystem--Regional monitoring program results, 1998
No abstract available.AuthorsAndrew J. Arnsberg, Brian E. Cole, James E. CloernOur evolving conceptual model of the coastal eutrophication problem
A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptuaAuthorsJames E. CloernPrimary food resources in the Sacramento-San Joaquin Delta
The Sacramento-San Joaquin River Delta, a complex mosaic of tidal freshwater habitats, is now a focus of ecosystem rehabilitation because of changes in critical functions associated with its geographic location at the landestuary interface. One of these functions is the production, transport, and transformation of organic matter that constitutes the “primary food supply,” that is, the food supplyAuthorsAlan D. Jassby, James E. Cloern