Objective(s) of the Research Project:
San Pablo Bay, a subembayment of San Francisco Bay, is subject to the influence of several major environmental stressors. These include: sediment loads; heavy metal and pesticide residues from California's Central Valley, the Sierra Nevada, and the coastal range; industrial waste from the San Francisco Bay Area (including several oil refineries); and chemical waste from the Mare Island Naval Shipyard (now closed).
An extensive set of potential indicators, including chemical, biochemical, and ecological variables, will be tested in designing a monitoring network that is temporally and spatially adequate to provide advance warning of the ecological impacts of natural and anthropogenic stressors. Two chemical measures of contaminant bioavailability, supercritical fluid extractability and aqueous desorption potential, will be used in investigating relationships between sediment-borne contaminant fluxes and toxicity. Biochemical indicators of toxicity will be analyzed in two sediment dwelling members of the San Pablo Bay food chain: the bivalve Macoma balthica and the crustacean Ampelisca abdita. Monitoring sensitive biochemical and cellular indicators of deleterious effects should foretell subtler and possibly longer term consequences of exposure to chemicals in the environment. Sublethal effects such as protein damage, lysosomal destabilization, metabolic alterations, and tissue damage will be compared to contaminant body burden and higher level effects such as growth and mortality. Ecological stress indicators to be considered include number and diversity of species within benthic assemblages, contaminant bioaccumulation in fish tissue, and reproductive success for two bird species, double-crested cormorants (Phalacrocorax auritus) and song sparrows (Melospiza melodia). Hatchability, clutch size and, for song sparrows, nestling survival will be evaluated as indicators of ecological condition.
Progress Summary/Accomplishments:
Substantial progress by all project participants has allowed most of the aims of the project to remain unchanged. The one exception to this relates to chemical analyses of fish and bird tissue. Due to an error in the original budget, insufficient funds were requested to perform these tasks (funds sufficient for 1 year were requested rather than funds for the full 3 years). Despite efforts to find alternative and supplemental sources of funding, we have been forced to scale back on the original aims.
During the second year, the second major deployment of continuous sampling equipment at the six "intensive" sites at the margins of San Pablo Bay was commenced on September 18, 2000. As in the previous deployment, the intention was to keep the equipment in place for two back-to-back 3-month deployments, as this greatly reduced the logistics. Funding for this deployment was not included within the original budget, and was leveraged from other sources. To complement this deployment, water and sediment samples are to be taken at monthly intervals at all these sites, along with samples at six other "intermediate" sites. Analysis of the earlier data has shown that the hydrodynamics of the system is controlled by the development of two types of convergence zones, one driven by barotropic pressure gradients and one created from converging baroclinic pressure gradients.
During this year, a variety of improvements were made in the methods used to collect, preserve, and analyze samples because of problems discovered in the initial methods. The delay in analyzing samples discussed in last year's progress report resulted in 18 months of samples being collected before the deficiencies were discovered. The result of these problems is that quantifiable organic chemical concentrations will be unavailable for samples collected between January 1999, and June 2000. More than 1 year of valid, quantified, and quality-assured monitoring data will still be collected, including during the entire second 6-month instrument deployment at the intensive sites. This should still be sufficient to achieve our initial project objectives, although the conclusions will be less robust.
The main biomarker and ecotoxicity studies have commenced. Esfenvalerate was shown to be highly toxic to the amphipod species A. abdita. Exposure of Macoma nasuta to some sediments resulted in significant mortality of clams as compared with a reference site. We are in the process of analyzing growth and bioaccumulation data. Tissue samples for biomarker analysis have been preserved and will be analyzed in the near future.
The ecological components (fish, cormorants, and song sparrows) have continued according to schedule (with the exception of the chemical analyses). Song sparrow nest success for both 1999 and 2000, was lower at our tidal marsh sites than at the Palomarin field station. At all sites in 1999 and 2000, overall nest survivorship was lower than 20 percent. These numbers are low, but further analysis is needed to determine whether this level of success may indicate a threat to population viability. Egg hatchability was similar in 1999 and 2000 with some notable exceptions.
Publications/Presentations:
Warner JC, Schoellhamer DH, Burau JB, Schladow SG. Tidal current phasing effects at the junction of two straits. Presented at the American Geophysical Union (AGU) Meeting, San Francisco, CA, 2000.
Warner JC, Schladow SG, Schoellhamer D, Burau J. Effects of tidal current phase at the junction of two straits. Presented at the 10th International Biennial Conference on Physics of Estuaries and Coastal Seas, 2000.
Schladow SG, Young T, Werner I, Warner JC, Veir J, Baum J, Pincetich C, Schoellhamer D, Thompson B, Davis J, Lowe S, Nur N, Spautz H, Roberts C, Fairey R, Ichikawa G, Crane D. CISNet San Pablo Bay network of environmental stress indicators. Presented at the Interagency Ecological Program (IEP) Annual Conference, Asilomar, CA, 2000.
Warner JC, Schladow SG, Schoellhamer D, Burau J. Napa-Sonoma Marsh hydrodynamic study for wetlands restoration. Presented at the 4th Biennial State of the Estuary Conference, San Francisco CA, 1999.
Future Activities:
The major oceanographic equipment deployments for the last phase of the project have commenced, along with the concurrent monthly water and sediment sampling. Trace element quantification, which has been hindered by the unplanned unavailability of an ICP-MS on the main University of California, Davis, campus should be greatly facilitated by the purchase of a new instrument, due to arrive in February 2001. One of the critical project goals is to relate contaminant fluxes to impacts in the San Pablo Bay ecosystem. It is hypothesized that fluxes of bioavailable compounds rather than total fluxes will control these impacts. To demonstrate this link in the laboratory, sediments from six sites are being analyzed to determine their toxicity to two test species, the accumulation of chemicals in the organisms and the chemical availability of the contaminants. The collection activities for the avian and fish components will continue as planned.
Due to the difficulty of completing an intensive 3-year data collection program and fully analyzing the data within the same time frame, we anticipate requesting an extension for a fourth year.
Supplemental Keywords: water, estuary, ecological effects, bioavailability, organism, cellular, chemicals, toxics, particulates, ecosystem, indicators, Pacific Coast.
Relevant Web Sites:
http://www.sfei.org http://www.engr.ucdavis.edu/~edllab
Original Project Abstract
1999 Progress Report
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Last Updated: June 6, 2002