Poster Presentations Anthropogenic Impacts Interacting influence of low salinity and nutrient pulses on the growth of bloom-forming Ulva compressa Guidone, M.; Steele, L. Sacred Heart University, Fairfield, CT 06825. [email protected] For the eastern US, it is predicted that climate change will increase the frequency of severe rainstorms, inundating coastal areas with pulses of freshwater that will reduce salinity but also temparily increase nutrients through sewage overflow and storm runoff. In an effort to predict how this may influence the frequency and severity of macroalgal blooms, this study examined the interacting effect of salinity and nutrient supply on bloom-forming Ulva compressa. In laboratory experiments with constant nutrient supply, U. compressa showed decreased growth at low salinities; however, this decrease was not detectable until the fifth day of treatment. Moreover, U. compressa demonstrated an extraordinary tolerance for freshwater, surviving for 48 hours without nutrients at 0 PSU. When exposed to pulses of freshwater (0 PSU) and varying nutrient levels (none, low, high) lasting either 0.5, 4, or 8 hours, U. compressa growth was negatively impacted in the treatment without nutrients and positively impacted by the low and high nutrient treatments. Furthermore, thalli in the high nutrient treatment showed increased growth with increased pulse time. These findings, combined with observations of U. compressa’s tolerance for high temperatures, suggest Ulva blooms will not decrease in frequency or severity with a change in precipitation patterns. Additional information: a) Faculty b) Poster c) Anthropogenic impacts; Community ecology d) No Long Term Effects of Anthropogenic Influences on Marine Benthic Macrofauna Adjacent to McMurdo Station, Antarctica Smith, S.1; Montagna, P.; Palmer, T.; Hyde, L. Harte Research Institute, Texas A&M University, Corpus Christi, Texas. [email protected] McMurdo Sound (Ross Sea, Antarctica) sediments have been influenced by contamination from adjacent McMurdo Station. Long-term monitoring of benthic communities provides a basis for assessment of impacts associated with human residency and known chemical waste disposal areas. The objectives of this study are: 1) to determine if any changes in benthic community abundance, biomass, and diversity occur over time, and 2) to investigate differences in benthic communities between polluted and unpolluted stations. Benthic cores were collected during the austral summer from 2000 to 2012 on three transects perpendicular to the shoreline with three stations (12, 24, and 36 m). Samples were sorted and macrofauna organisms were identified to the lowest identifiable taxon level possible. Macrofauna community structure has changed over time, but it is unknown if change is due to changes in contaminant exposure or natural, long-term variation. However, there is a significant decrease in some contaminants over time at two impacted stations. The macrofaunal community near the former wastewater outfall has recovered since a wastewater treatment plant was installed at McMurdo Station. These results indicate historical pollution has caused negative effects on sediments, but recent management actions have improved the environmental conditions adjacent to McMurdo Station. Presenting author status: Grad Preferred Presentation type: Poster Topic Area Preference: Anthropogenic Impacts, Community Ecology Non-target effects of mosquito control pesticides on the sub-lethal stress and survival of coral larvae Amanda Andersen1, Kevin Olsen1, Chelsea Metzgar1, Richard Pierce2 and Cliff Ross1 1Department of Biology, University of North Florida, Jacksonville, FL 32224 2 Mote Marine Laboratory 1600 Ken Thompson Parkway, Sarasota, FL34236 Abstract As coral cover declines on a global scale, coral communities are facing unprecedented levels of environmental stress. Survival, settlement, and health of coral larvae are a special concern because successful coral recruitment is critical to the maintenance and recovery of coral reefs. Mosquito control pesticides are a potential local stressor found in the Florida Keys, while elevated temperatures act on a global scale. To assess the effects of pesticides and elevated temperature (independently and in combination) larvae of the coral Porites astreoides were exposed to selected concentrations of the mosquito control pesticides Dibrom® and Permanone® 30-30 (0.0, 0.1, 1.0, 10.0 μg/L) at either ambient (27⁰C) or elevated (30⁰C) temperatures for 17 h. Post-exposure, larvae were evaluated for survival, settlement and signs of sub-lethal oxidative stress. While elevated temperature or exposure to permethrin failed to have any impact on the endpoints examined in this study, high levels of Dibrom® (≥1.0 μg/L) were found to cause a significant reduction in P. astreoides survival. These data suggest that ecologically relevant concentrations of pesticides that are associated with coastal runoff and tidal transport may only have a negligible impact upon larval health and survival. Presenting Author Status: Undergrad Presentation Type: Poster Topic Area Preferences: 1) Anthropogenic Impacts, 2) Recruitment/ Larval Ecology Ultrastructure and Calcification in the Coral Porites astreoides Under Ambient and Low pH Conditions Dungan, A. 1; Blackwelder, P. 1,2; Renegar, D. A.1; Peach, K. 3 1National Coral Reef Institute, Nova Southeastern University, Dania Beach, FL 33304; 2 MGG-RSMAS and Center for Advanced Microscopy, University of Miami, Coral Gables, FL 33124; 3Florida Atlantic University, Boca Raton, FL 33431 [email protected] Reduced surface ocean water pH, driven by ocean acidification, is emerging as one of the most significant threats to marine calcifying organisms. This process decreases the bioavailability of carbonate crucial to coral calcification. Additionally, a stable pH is necessary to maintain cellular function of marine tissues. The International Panel on Climate Change (IPCC) predicts that by 2100 the pH of surface ocean waters will drop an additional 0.14 - .35 units. The question remains whether coral ultrastructure (cell structure and components) will be significantly compromised at low pH environments. This research will quantify fine and ultrastructural differences in tissue and calcification response of Porites astreoides when exposed to ambient and high levels of carbon dioxide to reduce pH. This project utilizes scanning electron microscopy (SEM) for visual evaluation of calcium carbonate crystals and transmission electron microscopy (TEM) for qualitative and quantitative evaluation of tissue changes. Results from this experiment may have the potential to play a role in establishing a threshold value of CO2 for coral survivorship. Presenting author status: Grad Preferred presentation: Poster Topic area preferences: Anthropogenic impacts, Reef ecology Size matters: Insecticide exposure may create selective pressure that favors juvenile blue crabs (Callinectes sapidus) K. Spain-Schroeder; D.L. Smee, Marine Ecology Laboratory, Department of Life Sciences, Texas A&M University – Corpus Christi, TX Adult and juvenile blue crabs (Callinectes sapidus) are an important predator in estuarine systems (e.g., oyster reefs, saltmarshes) and serve as a food resource for several species, including humans. Populations are declining in many regions, and in some cases, smaller bodied crabs are becoming more frequent than larger bodied crabs. This trend is commonly attributed to fishing pressure, but exposure to pesticides from mosquito abatement programs and storm run- off may also be a factor. Adult and juvenile blue crabs were exposed to three insecticides (malathion, carbaryl, resmethrin) and a synergist (PBO), individually and in combination; lethal and sublethal effects (e.g., behavior, reflexes, coordination) were recorded every 12-hrs for 7 days. Effective lethal/sublethal exposure levels varied with pesticide, but exposure generally reduced coordination, decreased neurological functioning and crabs were less able to respond to stimuli. Resmethrin +/- PBO treatments were more toxic than individual carbaryl and malathion treatments. Mixture treatments increased lethal/sublethal effects compared to single-pesticide treatments for both life stages. Juvenile and adult blue crabs responded similarly to malathion and carbaryl, but adults were consistently more susceptible to resmethrin, PBO and mixture treatments than juveniles. These results suggest that toxicant exposure may create a selective pressure that favors juvenile stages. (a) Grad (PhDc) (b) Poster (c) Topic Area Preference: Anthropogenic Impacts and/or Behavior (d) Presentation Recording and Evaluation: YES! Benthic Fauna and Beach Stability on Delaware Bay Beaches: Major Storms and Seasonal Changes Affect Spatial Distributions Meghan Owings; Doug Miller; Danielle Ferraro; Art Trembanis School of Marine Science and Policy, College of Earth, Ocean, and Environment, University of Delaware, Lewes, Delaware 19958 USA [email protected], [email protected], [email protected], [email protected] Beach surveys have shown events like Superstorm Sandy and nor’easter Karen erode 10’s of cm from the beachface, followed by a more gradual redeposition over months. This “signature” of rapid erosion and incremental accretion may affect beach fauna at all tidal levels from the dune line down to sandbuilder (Sabellaria vulgaris) worm reefs low in the intertidal, where present. In the summer of 2013, we initiated monthly surveys for beach fauna: mole crabs (Emerita talpoida), amphipods