TA4 Integrating Sublethal Responses and Ecologically Relevant Endpoints
204 Oregon Ballroom
8:00 AM - 12:00 PM, Tuesday
() Complementing the Eco-Risk Paradigm: Indicators of Toxicant Exposure and Effect in Salt Marsh Species.
Anderson, S1, Brooks, A2, Cherr, G1, Higashi, R1, Morgan, S1, Nisbet, R2, Ustin, S1, Carr, R3, 1 University of California at Davis, Davis, CA, USA2 University of California at Santa Barbara, Santa Barbara, CA, USA3 US Geological Survey, Corpus Christi, TX, USA
ABSTRACT- Ecological risk assessment in estuarine systems relies heavily on use of toxicity tests, analytical chemistry, and ecosystem census to estimate risk to aquatic life. While this approach has been valuable for many management goals over at least two decades, complementary approaches are needed. These should provide improved: linkage to the ecological system under investigation, assessment of multiple stressors, procedures for spatial, temporal, or biological scaling. We propose a complementary framework in which chemical exposures and effects are characterized in strategically-selected salt marsh species at multiple scales. This makes possible: 1) direct evaluation of ecologically-relevant responses and 2) analysis and diagnosis of multiple stressors. We sampled several marsh sites in Northern and Southern California for population-level and biomarker responses in wetland plants, shore crabs (Pachygrapsus crassipes), and mudsucker fish (Gillichthys mirabilis). We also conducted analytical chemistry and ecosystem censuses at each site. A comparison to toxicity test responses has been performed at a more limited number of stations. Data for a key marsh restoration site indicate that the application of toxicity tests to the salt marsh environment is limited by ammonia interferences; however, toxicity attributable to organic compounds is implicated. Data on resident species includes: decreased biomass (by remote sensing and field measurement) of wetland plants as well as endocrine disruption and apoptosis in mudsuckers. More preliminary findings also point to decreased reproductive success in shore crabs and depressed growth rates of fish relative to reference sites. These data indicate that an integrated suite of techniques linking sublethal effects to ecologically relevant endpoints in resident organisms may provide practical information that can be used to inform decisions about marsh restoration and monitoring. This research has been supported by a grant from the EPA's Science to Achieve Results (STAR) Estuarine and Great Lakes (EaGLe) program through funding to the Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium, US EPA Agreement #R-82867601.
Key words: saltmarsh, wetlands, biomarkers