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November 2000

Tomales Bay Ecosystem Concerns Discussed

By Elena Belsky

The fourth State of Tomales Bay Conference (last held in 1992) met for two days in early October, sponsored by the Environmental Action Committee, Inverness Foundation, Tomales Bay Association, Point Reyes National Seashore, Gulf of the Farallones National Marine Sanctuary and the University of California Cooperative Extension/Sea Grant, with support from many volunteers. Speakers and moderators donated their time, with financial support for the Conference coming from various governmental, non-profit and individual grantors.

The organizers succeeded in presenting an excellent range of local speakers, government scientists, and academic researchers, with important discussion time after each presentation. Topics covered included watershed management issues; invasive specie-both plant and animal; endangered species-behavior, restoration & habitat; significant factors affecting water quality; and hydrology and tidal actions of the bay and it's tributaries. Local and governmental efforts to address the various critical issues were also discussed.

A pervasive theme throughout the Conference was the importance of a science based approach to watershed and water quality management. Also, repeatedly pointed out was the fact that because ecosystems are so interconnected and complex, we do not have enough overall information about their nature to provide us with a clear idea of what our interference will do. Therefore we don't really have an adequate understanding of what effects, positive, negative (or none at all), our "restoration" efforts might bring, and that it is important to remember this when considering action.

Standout presentations were given by Dr. Debra Ayres of UC Davis, "Spartina in Tomales Bay-Friend or Foe?" ; Dr. Randy Chambers, "LMER/BRIE Studies 1987-1995", and Dr. Rick Bennett, "Seasonal and Spatial Distribution of Coliform Bacteria and E.coli in a Rural California Estuary."

Dr. Ayres is a scientist at UC Davis, specializing in estuarine ecology and the introduced marsh plant Sparitna alterinflora. Her startling and forewarning lecture was a wake up call to everyone in attendance that morning. A prolific and mutative invasive species of cordgrass has taken over native stands of cordgrass in the northern pacific coast bays and more locally, marshes in the San Francisco Bay. Although currently unaffected, tides and storm surges could easily transport foreign spores and seed from SF Bay into Tomales Bay.

The profound effects eastern cordgrass (spartina alterniflora) has demonstrated in the Pacific Coastal areas, in it's hybridization with our native cordgrass (spartina foliosa) and subsequent hostile takeover, is cause for alarm. It chokes out native cordgrass by interbreeding, creating a more adaptive form of Spartina which successfully eliminates all other plant species from the marsh. So far, the only method of eradication of the invader and it's hybrid, is to destroy the marsh - either by removal of the topsoil/mud or by using repeated doses of Round Up. Dr. Ayres urged people working or recreating on the Tomales Bay to notify her of any suspicious cordgrass stands - Barbara Moritsch, plant ecologist at PRNS stated she is also available for consultation.

Dr. Randy Chambers, holds a Ph.D in Environmental Sciences from the University of Virginia, and is currently associate professor of biology at Fairfield University in Connecticut. Dr. Chambers has been involved in recent studies on ecology of estuaries, invasive plants and sediment chemistry in the Florida Everglades. During an 8-year study, primarily in the early 1990s, he spent hundreds of hours taking direct measurements of various parameters from a rubber dinghy on the Tomales Bay. In particular, Chambers measured eutrophication (the rate of supply of organic material) to the Bay, using mud cores, from which he believes he has pieced together a picture of the long-term impacts of terrestrial and oceanic organics on the Bay ecosystem over the last several hundred years. Dr. Chambers research might give insight into whether human activities are creating permanent changes in the Bay.

Dr. Rick Bennett has a Ph.D in Comparative Pathology from U.C. Davis; his interests include the effects of agricultural and urban land use on surface water microbiology, and has done multi-year studies in Marin and Sonoma Counties monitoring urban and rural water quality. Along with four other colleagues, Dr. Bennett conducted extensive Coliform bacteria and E.coli testing and monitoring in Tomales Bay in 1997-98. Sampling in two wet seasons, at 84 sample sites at the mouths of the tributaries and throughout the entire shoreline of Tomales Bay. The data revealed that fecal bacterial contributions to the Bay are wet season related, and suggests that there is a "reservoir of fecal bacteria feeding into the Bay".

It was generally held by the scientific community, that E.coli bacteria degraded rapidly, and only propagated in the intestines of mammals - but that turns out to be incorrect; E.coli can survive for prolonged periods of time in silt and mud AND reproduce. Sediment E.coli concentrations were "three to five times greater than in the water column", according to Dr. Bennett. Also discussed was a very recent study by Dr. Marilyn Yeats, uncovering evidence that even in good, deep soils, viruses can travel 300 feet away from it's underground discharge source. Both of these new findings indicate a drastic departure from previous beliefs, and merit serious consideration for public health and safety. Such a gathering of knowledgeable people, sharing their studies, encouraging others to learn is of tremendous value, as is inspiring people to continue to work for the health of Tomales Bay and environs. Hopefully it won't be another eight years before we all gather for another State of the Tomales Bay Conference.

There was much additional technical information presented, in numerous subjects, all worth the time to read carefully. According to Conference organizers, a complete syllabus will made available in book form and on CD-ROM. Contact the Tomales Bay Advisory Committee, PO Box 684, Inverness CA 94937 for ordering information.

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