California Water Science Center

Aquatic Ecosystems

Aquatic ecosystems information and data is neccessary for many California water management decisions including preservation of California's natural resources. The California Water Science Center conducts interdisciplinary research from aquatic species behavioral, population and community ecology, to the effects hydrologic extremes and climage change on ecosystems.  

Filter Total Items: 76
Date published: August 11, 2021
Status: Active

Investigation of Groundwater and Surface Water Interactions in Support of Ecosystem Management at San Sebastian Marsh, California

To help the U.S. Bureau of Land Management determine the long-term sustainability of the San Sebastian Marsh, and its critical role for the survival of the endangered desert pupfish (Cyprinodon macularius), the USGS is evaluating the potential interactions and relation between groundwater and surface water at the San Sebastian Marsh.

Contacts: Gregory Mendez
Date published: June 1, 2021
Status: Active

Biogeochemistry Group

The Biogeochemistry (BGC) Group uses an interdisciplinary approach to address surface water quality issues and food web dynamics throughout California, particularly in the Sacramento-San Joaquin Delta and San Francisco Bay.

Date published: March 4, 2021
Status: Active

State of the Network: Long-Term, High-Frequency Flow and Water Quality Data in the San Francisco Estuary, California

The San Francisco Bay and Sacramento-San Joaquin Delta form one of the largest estuaries in the United States. Water flow and water quality in the San Francisco Bay-Delta Estuary are important to the economies of both California and the nation. The Bay-Delta system provides water to more than 25 million California residents and vast farmlands, as well as key habitat for birds, fish, and other...

Date published: February 10, 2021
Status: Active

Longfin Smelt Distribution in the Coastal Pacific Ocean

Longfin Smelt (Spirinchus thaleichthys) is a pelagic fish species found in waters along the Pacific coast, from Alaska to central California. Its complex life cycle makes it vulnerable to threats in both freshwater and at sea. Longfin Smelt is listed as a threatened species by the state of California.

Date published: January 20, 2021
Status: Active

Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta

Sediments represent an important pool of nutrients in the Sacramento-San Joaquin Delta (Delta). The exchange of nutrients between the water column and the benthos impacts water quality and effects phytoplankton, harmful algal blooms, aquatic vegetation, and drinking water quality. To date, there is very limited information about nutrient pools in Delta sediments, nor how these nutrients are...

Date published: November 20, 2020
Status: Active

Ecosystem Engineering Impacts of Water Primrose in the Sacramento-San Joaquin Delta

Many non-native fish, invertebrates, and plants have colonized the Sacramento-San Joaquin Delta (Delta) of California, the landward most region of the San Francisco Estuary. Included among these invasive species is the water primrose (Ludwigia spp.), an aggressive floating aquatic plant that is native to South and Central America and parts of the US, but invasive in California. Water primrose...

Date published: November 2, 2020
Status: Active

Selenium Hazard in the Salton Sea Environment, Summary of Current Knowledge to Inform Future Science

The effect of selenium (Se) toxicity on wildlife has been known for more than 50 years. The threat of Se contamination gained greater attention from federal agencies in the 1980s due to the observation of embryo deformity and mortality in birds at a National Wildlife Refuge in California. Harmful effects from Se were determined to be connected to irrigation drainage water.

As a result,...

Date published: August 5, 2020
Status: Active

Evaluating the effects of wastewater-derived nutrients on phytoplankton abundance and community structure in the San Francisco Estuary and Delta

Planned upgrades to the Sacramento Regional wastewater treatment plant (SRWTP) will substantially reduce nutrient discharge and also alter the types and amounts of nutrients being distributed across the San Francisco Delta and Estuary (Delta).

One highly anticipated outcome of lower nutrients is improved productivity in the phytoplankton communities that supply aquatic food webs, which...

Date published: July 15, 2020
Status: Active

Modeling Nitrogen Reduction Benefit to Invasive Aquatic Vegetation vs. Native Phytoplankton

Phytoplankton comprise the bottom of the aquatic food web and the abundance of phytoplankton serves as an indicator of healthy aquatic habitats. In the Sacramento-San Joaquin River Delta (Delta), competing with phytoplankton for required nitrogen, invasive aquatic vegetation (IAV) has increased exponentially in recent years. Once established, IAV can negatively impact local ecosystems and...

Date published: June 26, 2020
Status: Active

Monitoring Cyanotoxins in California's Sacramento-San Joaquin Delta: Fixed Stations and High-Resolution Mapping Surveys

California’s Sacramento-San Joaquin River Delta (Delta) provides drinking water to about 30 million people and irrigation water to the agriculturally rich Central Valley. The Delta is also home to numerous threatened and endangered native species. The health of the Delta's aquatic ecosystems, and fish in particular, have long been in a state of decline. This is associated with decreasing...

Date published: August 27, 2019
Status: Active

Mercury studies at Sulphur Bank Mercury Mine and Clear Lake, California

The abandoned Sulphur Bank Mercury Mine on the shores of Clear Lake in Northern California has been designated as a "Superfund Site" by the U.S. Environmental Protection Agency (EPA). This means that the EPA has determined that the area is contaminated by hazardous waste and requires cleanup because it poses a risk to...

Date published: July 24, 2019
Status: Active

Organic Matter Research Laboratory

The USGS California Water Science Center's Organic Matter Research Laboratory provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy along with standard measurement of total dissolved organic carbon and nitrogen concentration.