Causes and Relevance of Phytoplankton Blooms in the Northern Sacramento-San Joaquin Delta Active
Phytoplankton are an important part of aquatic food webs and ecosystems. These single-celled plants grow faster in the stronger light of spring or summer, resulting in population explosions called phytoplankton blooms. These blooms in turn feed zooplankton (free-floating aquatic microorganisms), providing food for many aquatic species, including fish, shrimp, crabs, and other invertebrates.
Phytoplankton blooms occur in most aquatic systems. One such system is California’s Sacramento-San Joaquin Delta. In recent years, the size and frequency of phytoplankton blooms have become inconsistent, creating a concern for the region’s food web. These fluctuations may be tied to many conditions, including changes in suspended sediment levels, water clarity, and the increased presence of nutrients and other contaminants.
In 2016 there were a rare series of large phytoplankton blooms that formed in the northern part of the delta. This offered scientists the opportunity to examine phytoplankton population increase and the benefits blooms provide to the lower food web. However , a lack of funds cut short the research needed for the publication of a conclusive report.
Objective
Scientists will examine data on recent phytoplankton blooms to better understand their formation. Using data from 2016, scientists will study the causes for that year’s upsurge. Scientists will research how increased levels of sediment, certain nutrients, and other contaminants, might inhibit such growth. Having more complete data on this topic will provide guidance on the release of such elements, and on the flow of sediment, into the delta. This information will assist in habitat conservation measures and research related to the restoration of the delta ecosystem.
Science Plan
Scientists will analyze data from samples of phytoplankton blooms from the 2016 study for water quality, nutrients, sediment, temperature, pH, and other relevant environmental factors. They will also use this data to support an inventory of nutrient mapping across delta. Data taken from other sources, such as monitoring stations, will also be examined and included. The goal of this research is to understand the relationship between phytoplankton growth and nutrient concentrations, temperature, light, time, water conditions, and other factors.
Below are publications associated with this project.
A river-scale Lagrangian experiment examining controls on phytoplankton dynamics in the presence and absence of treated wastewater effluent high in ammonium
Adjustment of the San Francisco estuary and watershed to decreasing sediment supply in the 20th century
Habitat connectivity and ecosystem productivity: implications from a simple model.
Phytoplankton fuels Delta food web
Phytoplankton growth rates in a light-limited environment, San Francisco Bay
Significance of biomass and light availability to phytoplankton productivity in San Francisco Bay
Below are partners associated with this project.
- Overview
Phytoplankton are an important part of aquatic food webs and ecosystems. These single-celled plants grow faster in the stronger light of spring or summer, resulting in population explosions called phytoplankton blooms. These blooms in turn feed zooplankton (free-floating aquatic microorganisms), providing food for many aquatic species, including fish, shrimp, crabs, and other invertebrates.
Phytoplankton blooms occur in most aquatic systems. One such system is California’s Sacramento-San Joaquin Delta. In recent years, the size and frequency of phytoplankton blooms have become inconsistent, creating a concern for the region’s food web. These fluctuations may be tied to many conditions, including changes in suspended sediment levels, water clarity, and the increased presence of nutrients and other contaminants.
In 2016 there were a rare series of large phytoplankton blooms that formed in the northern part of the delta. This offered scientists the opportunity to examine phytoplankton population increase and the benefits blooms provide to the lower food web. However , a lack of funds cut short the research needed for the publication of a conclusive report.
Objective
Scientists will examine data on recent phytoplankton blooms to better understand their formation. Using data from 2016, scientists will study the causes for that year’s upsurge. Scientists will research how increased levels of sediment, certain nutrients, and other contaminants, might inhibit such growth. Having more complete data on this topic will provide guidance on the release of such elements, and on the flow of sediment, into the delta. This information will assist in habitat conservation measures and research related to the restoration of the delta ecosystem.
Science Plan
Scientists will analyze data from samples of phytoplankton blooms from the 2016 study for water quality, nutrients, sediment, temperature, pH, and other relevant environmental factors. They will also use this data to support an inventory of nutrient mapping across delta. Data taken from other sources, such as monitoring stations, will also be examined and included. The goal of this research is to understand the relationship between phytoplankton growth and nutrient concentrations, temperature, light, time, water conditions, and other factors.
- Publications
Below are publications associated with this project.
A river-scale Lagrangian experiment examining controls on phytoplankton dynamics in the presence and absence of treated wastewater effluent high in ammonium
Phytoplankton are critical component of the food web in most large rivers and estuaries, and thus identifying dominant controls on phytoplankton abundance and species composition is important to scientists, managers, and policymakers. Recent studies from a variety of systems indicate that ammonium ( NH+4) in treated wastewater effluent decreases primary production and alters phytoplankton speciesAuthorsTamara E. C. Kraus, Kurt D. Carpenter, Brian A. Bergamaschi, Alexander Parker, Elizabeth B. Stumpner, Bryan D. Downing, Nicole Travis, Frances Wilkerson, Carol Kendall, Timothy MussenAdjustment of the San Francisco estuary and watershed to decreasing sediment supply in the 20th century
The general progression of human land use is an initial disturbance (e.g., deforestation, mining, agricultural expansion, overgrazing, and urbanization) that creates a sediment pulse to an estuary followed by dams that reduce sediment supply. We present a conceptual model of the effects of increasing followed by decreasing sediment supply that includes four sequential regimes, which propagate downAuthorsDavid H. Schoellhamer, Scott A. Wright, Judith Z. DrexlerHabitat connectivity and ecosystem productivity: implications from a simple model.
The import of resources (food, nutrients) sustains biological production and food webs in resource-limited habitats. Resource export from donor habitats subsidizes production in recipient habitats, but the ecosystem-scale consequences of resource translocation are generally unknown. Here, I use a nutrient-phytoplankton-zooplankton model to show how dispersive connectivity between a shallow autotroAuthorsJames E. CloernPhytoplankton 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-SolgerPhytoplankton 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. CloernSignificance of biomass and light availability to phytoplankton productivity in San Francisco Bay
Primary productivity was measured monthly at 6 sites within San Francisco Bay, USA, throughout 1980. The 6 sites were chosen to represent a range of estuarine environments with respect to salinity, phytoplankton community composition, turbidity, and water depth. Annual net production over the photic zone ranged from 95 to 150 g C m-2, and was highest in regions of lowest turbidity. Daily photic zoAuthorsBrian E. Cole, James E. Cloern - Partners
Below are partners associated with this project.