Introduction

Our lab reflects the interest of the Marine Invasion Research Laboratory in studying patterns and processes of marine invasions over broad spatial scales. Working with our counterparts in Maryland and Oregon, researchers here pursue studies that compare the biological diversity and impacts of invasive species in waters on the Atlantic and Pacific coasts. We are investigating demographic and ecological differences among populations of invertebrates in their native (East Coast) and invaded (West Coast) ranges. In collaboration with the National Ballast Information Clearinghouse, we also help track shipping and ballast water delivery patterns and link these to onboard densities of organisms, to better understand inoculation and invasion rates in West Coast ports.

Our mission is two-fold: (1) to serve as a focal point for such comparative work conducted in the San Francisco Bay Estuary and along the California coast and (2) to increase the scope of research on invasion ecology in San Francisco Bay, in collaboration with researchers in the Bay Area and elsewhere.

We are housed at San Francisco State University's marine research and teaching facility, the Romberg Tiburon Center . Our bayside location in Marin County, north of the city of San Francisco, allows for easy access to field sites in the North, Central and South bays. Collaborators at RTC include Wim Kimmerer , Sarah Cohen (SFSU) and Drew Talley (San Francisco Estuarine Research Reserve). Other Bay Area collaborators include USGS , Port of Oakland and Point Reyes Bird Observatory .

Setting

San Francisco Bay is the second largest estuary in the nation and the largest on the Pacific Coast. Including the Delta region, where the Sacramento and San Joaquin rivers converge, the Bay estuary encompasses more than 1,600 square miles and drains 40 percent of California's water. As an important stop for migratory birds using the Pacific Flyway, the Bay is also home to hundreds of animal and plant species, including many endemics.

San Francisco Bay Estuary is a highly altered ecosystem. During the past 160 years, environmental disturbance of the estuary and its surroundings by humans has escalated dramatically. Some 80 to 90 percent of wetlands and riparian areas have been lost as a result of draining, filling and sedimentation; some 40 percent of the freshwater input is diverted for agricultural and urban uses; and major cities with industry, busy ports, and shipyards line the shores of the estuary.

One result of intense human use is the high number of non-native species found in the Bay. With more than 200 introduced protists, plants, invertebrates, fish and other vertebrates reported from the estuary, and with more non-natives discovered every year, San Francisco Bay has been called the most invaded aquatic ecosystem in North America. Although the impacts of most of these invaders are unknown, a handful of highly abundant non-natives have greatly altered the Bay ecosystem. Examples include: the Asian clam Potamocorbula (Corbula) amurensis, which, through its filter-feeding, has dramatically reduced phytoplankton populations in the northern part of the Bay; and the Atlantic cordgrass Spartina alterniflora, which changes sediment dynamics, converting mudflats into meadows and hybridizes with the native cordgrass, resulting in local extirpations.

Projects involving MIRL's California Lab at RTC

Population Ecology : Key demographic characteristics of three species are being compared between native (East Coast) and invading (West Coast) populations.

Community Ecology : Surveys and manipulative field ecology experiments are being used to examine species richness and diversity in fouling communities, spatial and temporal differences in these communities, and the effects of key species on community assembly and diversity.

Eradication: Manual removal and heat treatments are being explored as possible eradication techniques for the rough periwinkle, Littorina saxatilis. Removals remain ongoing for an isolated population of the Atlantic common periwinkle, Littorina littorea, at Don Edward National Wildlife Refuge in Fremont, Calfornia. Additionally, in November 2002, personnel from the California Department of Fish and Game, NOAA Fisheries/Restoration Center, the Port of Redwood City, U.S. Fish and Wildlife Service, the University of California, Davis, the California Coastal Conservancy, the San Francisco Estuary Institute, the Smithsonian Environmental Research Center, and San Francisco State University's Romberg Tiburon Center for Environmental Studies conducted a systematic manual removal of a western Atlantic brown alga, Ascophyllum nodosum, from a site in Redwood City. Frequent monitoring of the site during the intervening 3 years indicates successful local eradication of the alga.

Patterns of Invasions Across West Coast Estuaries: Patterns of species richness and diversity in fouling communities along latitudinal gradients and across salinity and wave exposure gradients within estuaries.

Ballast Water Exchange Verification : There is no commercially available technology to verify whether ballast water has been exchanged, as required by law. During the past 4 years, SERC and the US Coast Guard have collaborated to identify and evaluate various chemical markers and associated analytical techniques to differentiate water of coastal versus oceanic origin. A research project expected to launch by the end of this year will continue to test the efficacy of these chemical tracers as indicators of proper ballast water exchange.

Hull Fouling : Remotely operated vessels equipped with video cameras will be used to examine the hulls of commercial ships in West Coast ports. The data gathered will be used to determine the effects of season, vessel type, speed, vessel husbandry, and route on the degree of hull fouling.

Light Trap Monitoring of Planktonic Larvae: We used light traps to collect planktonic larvae, focusing on the spatial and temporal distribution and abundance of the Chinese Mitten crab, Eriocher sinensis. This work was part of a larger project in the San Francisco Bay-Delta system, which is addressing the potential transport of larvae to estuaries, especially in the Pacific Northwest, in the ballast water of container ships from the San Francisco Bay-Delta system.