Oral Presentations Anthropogenic Impacts
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Oral Presentations Anthropogenic Impacts Impact of bottom trawling on meiobenthos off Kakinada, East coast of India Annapurna, C Department of Zoology, Andhra University, Visakhapatnam- 530 003, India [email protected] The present work envisages a comprehensive study of the species composition, abundance and biomass of meiobenthic fauna, in general and impact of bottom trawling on meiobenthos in particular off Kakinada Bay, east coast of India, which is an important fishing ground and a nursery area for juvenile fish. Two sampling corridors were established at 50-65 m namely Trawling Experimental Corridor (TEC) and a Reference Corridor (RC). The area covered by Trawling Experimental Corridor (TEC) is approximately 15*2 km and by Reference Corridor (RC) is approximately 15*1 km. The sediment nature and physico – chemical parameters of the ambient milieu were also studied to explain spatial and temporal variations of the meiobenthic abundance and biomass in relation to impacts of bottom trawling. During the present study an attempt was made to study the responses for meiobenthic taxa. The magnitude of response of each variable to the fishing treatment was calculated by Meta analysis and explained the cause and effect relationship of trawling and meiobenthic population. From the data it is observed that nematodes and polychaetes in terms of abundance and biomass have shown a negative impact on the trawling in the study area. Presenting author status: Faculty Preferred Presentation type: Oral Topic area of preference: Anthropogenic Impacts, Biodiversity A Disturbance in the Force: Copper Impairs Herbivore Response Towards Seaweed Inducible Defenses Warneke, A.M.; Long, J.D. San Diego State University, San Diego, CA 92182. [email protected] Herbivory plays a quintessential function in controlling seaweed communities. Seaweeds often counter herbivore pressure through morphological or chemical modifications. Several biotic and abiotic factors have exhibited influence over these interactions, yet the roles of anthropogenic stressors are less understood. The objective of this study was to examine the effect of copper on herbivore perception of seaweed inducible defenses. To investigate these interactions within a contaminant context, we subjected the brown seaweed Silvetia compressa and the herbivorous snail Chlorostoma funebralis to an initial grazing period (induction phase) and a subsequent bioassay phase in the presence and absence of copper (50 ug/l). Preliminary results indicate that under uncontaminated settings, nongrazed tissues were more palatable than previously grazed tissues. This confirmed the presence of inducible defenses in Silvetia. However, copper additions prevented snails from distinguishing between control and previously grazed tissues. Further experiments have confirmed that this behavior persists only when herbivores have been copper exposed for an extended duration of time. This study is the first to demonstrate that contaminants can act as stressors by reducing the effectiveness of seaweed inducible defenses. Overall, this information will allow us to predict how communities will shift in response to rapidly changing aquatic environments. Presenting author status: Grad Preferred Presentation type: Oral Topic Area Preference: Anthropogenic Impacts; Community Ecology Presentation Recording and Evaluation: Yes Light requirements of seagrasses determined from historical records of light attenuation Choice, Z. D.1,2; Frazer, T. K.2,3; Jacoby, C. A.4 1USDA Forest Service, Southern Research Station, Center for Bottomland Hardwoods Research, Oxford, MS 38655 2School of Natural Resources and Environment, University of Florida, Gainesville, Florida 32611 3Fisheries and Aquatic Sciences Program, School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32653 4Department of Soil and Water Science, University of Florida, Gainesville, Florida 32653 [email protected] Seagrasses around the world are threatened by human activities that degrade water quality and reduce light availability. In this study, light requirements were determined for four common and abundant seagrasses along the Gulf coast of peninsular Florida using a threshold detecting algorithm. Light requirements ranged from 8-10% of surface irradiance for Halophila engelmannii to 25-27% of surface irradiance for Halodule wrightii. Requirements for all species differed from previous reports generated at other locations. Variations were attributed to morphological and physiological differences, as well as adaptation to light histories at specific locations. In addition, seagrasses were absent from stations with significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a and color. These results confirm the need to address links between increased anthropogenic nutrient loads, eutrophication, reduced light penetration, and loss of seagrasses and the services they provide. Presenting author status: Faculty Presentation Preference: Oral Topic Area Preferences: Anthropogenic Impacts and/or Conservation and Management Presentation Recording and Evaluation: Yes Deep-sea harpacticoid families expand the scope of impacts of the Deepwater Horizon oil spill and provide family-level indicators of tolerance and sensitivity Baguley, J.G.1; Bang, H.W.1; Moon, H.1; Montagna, P.A.2 1Department of Biology, University of Nevada, Reno, NV 89557; 2Texas A&M University-Corpus Christi, Corpus Christi, TX 78412. [email protected] In response to the Deepwater Horizon (DWH) oil spill, a large-scale investigation was initiated to elucidate potential impacts to biological communities across the northern Gulf of Mexico. Deep-sea benthic soft-sediment communities and environmental variables were sampled at 68 high-priority stations during September-October 2010 response cruises aboard the R/V Gyre and R/V Ocean Veritas. The DWH deep-sea benthic footprint, and identified impacts to major meiofaunal and macrofaunal taxa, extends to 5 km in all directions around the wellhead and up to 17 km to the southwest. Here, we test the hypothesis that benthic impacts can be more finely resolved if a higher degree of taxonomic resolution is provided. For this purpose, Harpacticoida were identified to the family level. Family-level indicators of tolerance and sensitivity have been identified. Reduced harpacticoid family diversity was found near the DWH wellhead and in the trajectory of the subsurfance plume. The harpacticoid community response suggests an expanded area of benthic impacts associated with the Deepwater Horizon blowout and oil spill. This expanded area of impacts is consistent with the trajectory of the subsurface oil plume and extends up to 90 km to the southwest of the wellhead. Presenting author status: Faculty Preferred presentation type: Oral Topic area: 1) Anthropogenic Impacts; 2) Community Ecology Nutritional status drives hypoxia tolerance in the Asian green mussel Perna viridis from Indonesia Huhn, M.1,2; Lenz, M.1; von Juterzenka, K1,2 1Bogor Agricultural University, Jl. Raya Darmaga Kampus, IPB Darmaga Bogor, 16680 West Java, Indonesia; 2GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany. [email protected] The Asian green mussel Perna viridis commonly occurs in anthropogenically impacted habitats where it survives under stressful conditions such as hypoxia. To test whether hypoxia tolerance is a consequence of habitat quality, e.g. through selection of stress-tolerant genotypes, we cross- transplanted mussels between the highly impacted Jakarta Bay and the pristine Lada Bay, Indonesia. After two months, we exposed mussels transplanted within (treatment control) and between (treatment) bays to hypoxia (0.5 mg/l dissolved oxygen) in the laboratory and monitored their survival during 14 days. Regardless of their origin, body condition indices (BCI, a measure for the nutritional status) and survival rates were significantly higher in mussels that spent the last two months in the pristine bay. This is in contrast to results from a similar study, in which hypoxia tolerance but also the BCI was higher in mussels from Jakarta Bay. This new picture suggests that the nutritional status is actually more important for hypoxia tolerance in green mussel populations than the quality of their habitat of origin. Therefore, a good nutritional status could mitigate detrimental effects of anthropogenic stressors in filter feeders. This is a relevant aspect for predicting the future of mussel populations in highly impacted coastal waters. Presenting author status: Grad Preferred presentation type: Oral Topic area preference: Anthropogenic impacts, Conservation and Management Evaluation of presentation: Yes Are cumulative impact indices an appropriate proxy for ecosystem health? Haupt, A.J.1; Baruch-Mordo, S.2; JBourque, J.3; Smith, S.4 1University of Massachusetts Boston; 2The Nature Consevancy; 3United States Geological Service; 4University of Michigan As humans expand current and planned uses of the ocean, it is increasingly important to understand how these impacts affect coastal ecosystems. A cumulative human impact score was created for the California Current by synthesizing fine-scale information on the distribution of multiple environmental stressors (Halpern et al. 2009). The resulting cumulative impact score is potentially useful to managers and policy makers, because it narrows a complex interaction of factors into a single number that can directly contribute to environmental