Research Areas > Nutrients > Nutrient Cycling in Estuaries > Eutrophication Magnitude & Extent > Bight '08 Coastal Wetlands and Estuaries

Project: Bight '08 Coastal Wetlands and Estuaries

Background and Objectives

Coastal Wetlands and Estuaries is a new work group for the Bight 2008 Regional Monitoring effort (Bight '08). The objectives of this study are to characterize the extent and magnitude of eutrophication in SCB estuaries, as well as the extent of sediment contamination in estuaries (in partnership with the Bight '08 Coastal Ecology project). Indicators for eutrophication include water column dissolved oxygen, primary producer biomass (macroalgae, brackish water submerged aquatic vegetation, sediment and surface water chlorophyll-a, and harmful algal bloom toxins). Sub-objectives are to:

a. Determine whether differences exist between estuarine classes (embayments, perennially tidal lagoons, seasonally tidal lagoons, nontidal lagoons, river mouth estuaries)
b. Determine the relationship between nutrient loads and estuarine biological response
c. Determine how muting of tidal forcing within an estuary impacts biological response to loads

Status

This project was initiated in 2007 with anticipated completion in 2011. Field sampling will occur from October 2008 to October 2009.

Methods

The basic approach to this eutrophication assessment is a probability-based survey in which sites were randomly selected from a comprehensive list of estuaries. Because eutrophication is likely to be spatially variable within an estuary, sampling will occur in target index areas within each selected estuary. Thus, reporting will provide the percent of estuaries impacted by eutrophication. The criteria for selecting an index area site included: 1) proximity to nutrient inputs; 2) residence time of the estuarine waters; 3) field crew safety and access; and 4) accessiblity for sampler deployment. Approximately 30 sites will be assessed throughout the Bight.

Four items will be assessed at each of these sites. First, dissolved oxygen and other water quality parameters will be continuously monitored. Second, primary producer biomass and percent cover (macroalgae, benthic diatoms, phytoplankton, brackish water submerged aquatic vegetation) will be monitored bimonthly. Stable istotope analysis will also be performed on select samples to identify relative contributions to nutrient loading. Third, harmful algal bloom (HABs) toxins (domoic acid and microcystin) will be monitored in the water column and in a subset of sediment samples from each of the habitat types of interest (marinas, ports, bays/harbors, and estuaries/lagoons). Fourth, estuarine nutrient loads will be modeled for each estuary sampled.

Partners

This project is being conducted in close cooperation with all of SCCWRP’s member agencies and other Bight '08 participants. In total, over 40 different organizations including regulated, regulatory, and non-governmental agencies are expected to collaborate on this project.

Presentation

Assessment of Eutrophication in Estuaries: Bight ‘08 Estuaries and Coastal Wetlands Study. January 2009 presentation to SCCWRP member agencies. Describes study design for examining the extent and magnitude of eutrophication in southern California estuaries.