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Climate, ocean acidification, and the changing oceans

Room: Carron A     2014-08-18; 15:00 - 17:00

NB: Unless specified otherwise, presentations are 15 minutes in length, and speed presentations are 5 mins in length.

Chair(s)/Moderator(s): Pawluk, Kylee

C3.1  15:00  Assessing the role of intertidal seagrass meadows as coastal carbon sink in Scotland. Maria Potouroglou *, EDINBURGH NAPIER UNIVERSITY; Karen Diele EDINBURGH NAPIER UNIVERSITY; Mark Huxham EDINBURGH NAPIER UNIVERSITY;

Abstract: Industrialisation and rapid population growth have caused an increase in greenhouse gas emissions. Increasing atmospheric CO2 levels are having severe impacts worldwide including changing weather patterns, ecosystem destruction and the loss of livelihoods. While the critical role of terrestrial ecosystems as source and sink of organic carbon (Corg) has been widely studied, the importance of carbon storage in vegetated coastal ecosystems-“Blue Carbon”- is increasingly being acknowledged quite recently. Eelgrass beds are well developed in Scotland, most likely due to the presence of extensive suitable habitats and uncontaminated waters. However, seagrasses in Scotland are poorly studied, with the most recent published estimates of their extent dating from 1993. Hence this study set as primary goal to provide an insight into the structure, abundance and distribution of intertidal Zostera spp., and evaluate the extent of Corg stocks in the relatively undocumented seagrass meadows. Preliminary results indicate a great range of organic carbon stored in both living seagrass biomass and the underlying soils. The overall contribution of Zostera beds to carbon storage is relatively large given their extensive coverage and broad distribution. This study provides a thorough description of seagrass carbon stocks from an underrepresented region and further contributes to the existing global database on seagrass meadow Corg storage.

C3.2  15:15  Ecological implications of introductions and invasions; the dominance of a novel introduced seaweed over a known invasive seaweed. Pawluk, KA *, University of Victoria; Cross, SF University of Victoria;

Abstract: Despite recent advances in the study of marine invasion ecology, there is a limited understanding of how multiple invasive species interact. Using seaweeds as a model system, we tested how two invasive species interact with each other and with the larger community of native seaweeds in Baynes Sound, British Columbia, Canada. Sargassum muticum is one of the four most widespread global invasive seaweeds with previously demonstrated negative impacts on native seaweeds; Mazzaella japonica is an introduced seaweed thus far only found in Baynes Sound, whose impacts on native communities have never been studied. Using a long-term removal experiment with three treatments and a control, we have been monitoring the recovery of native seaweed communities in Baynes Sound. Preliminary results reveal a significant change in the seaweed community within the treatment plots. Removal of both introduced seaweeds and removal of only M. japonica have similar effects with a marked increase in both number and percent cover of native seaweeds compared to the removal of only S. muticum. Comparison of S. muticum and M. japonica removal on the success of the other introduced species suggests that M. japonica could be outcompeting S. muticum. Our study shows that poorly known introduced seaweed may be outcompeting a well studied aggressive invasive species, with possibly significant impacts on marine seaweed communities in Baynes Sound.

C3.4  15:45  The paradoxical roles of climate stressors on disturbance and recovery of coral reef ecosystems at Little Cayman Island. Manfrino, C *, Central Caribbean Marine Institute & Kean University, School of Environmental and Sustainability Sciences; Foster, G Central Caribbean Marine Institute; Foster, K. Little Cayman Research Centre, Central Caribbean Marine Institute;

Abstract: Six closely-spaced high-temperature events impacted the Caribbean between 1987 and 2009. The 1998 global ENSO event resulted in significant mortality at Little Cayman where live coral cover decreased by 40%. Subsequent annual monitoring revealed no significant recovery until 2009-2011, when a rapid rebound to pre-disturbance levels occurred. We report here the biophysical and hydrologic factors pertinent to reef resilience and describe the various roles climatic disturbances have played in this rapid recovery. The step-change in coral recovery is indicative of several episodic events. While numerous thermal stress events may have initially limited growth and recovery, the rapid cooling effect of frequent Tropical Storms and Hurricanes led to rapid regeneration. Future studies will illustrate the role of local hydrography as they pertain to recovery from climate stress with global applications for coral reefs.

C3.5  16:00  Rapid, high definition, automated underwater sensing of coral reef ecosystems: The Catlin Seaview Survey. Neal, Benjamin Paul *, Global Change Institute, University of Queensland; Beijbom, Oscar University of California San Diego; Mitchell, Greg University of California San Diego; Gonzalez-Rivero, Manuel Global Change Institute, University of Queensland; Hoegh-Guldberg, Ove Global Change Institute, University of Queensland;

Abstract: Coral reefs worldwide are suffering dramatic declines. An estimated 40% of coral reef habitat has been affected within the last 50 years due to a suite of factors, including pollution, overfishing, destructive fishing and climate change, affecting some 500 million people globally who rely on coral reefs for food, tourism income and coastal protection, along with extensive impacts to the still partially unknown biodiversity of these ecosystems. In response to this issue, the Catlin Seaview Survey is creating a baseline record of coral community composition over 150 worldwide coral reef locations, using multi-camera, high-resolution, panoramic underwater imaging. These images are processed by a novel, computer-vision driven, automated benthic image analysis system capable of producing summary statistics of population and community composition. This system, called CoralNet, reduces underwater ecological image processing time by at least two orders of magnitude, making this a valuable tool for many field managers. This paper will present both the underwater imaging and benthic community analysis processing systems in detail, along with coral reef case studies and data from the Caribbean, The Great Barrier Reef, and the Coral Triangle. The standardised data produced by this project enables comparison for the first time of impacts and changes to coral reef ecosystem across large-scale world regions and across differing regimes of anthropogenic and natural disturbances.

C3.6  16:15  Building the Atlas of Coral Resistance: Mapping Coral Thermal Tolerances across Water Quality Gradients. Oliver, TA *, University of Hawaii; Logan, C California State University Monterey Bay; Barshis, D Old Dominion University; Gates, R University of Hawaii, HIMB;

Abstract: Reefs sites globally face compounding threats from local pollution and overfishing, as well as the global threat of rising temperatures. To both investigate the linkages between these threats and inform the public about them, we are working with local communities and stakeholders across multiple sites in American Samoa, to (a) spatially map coral critical thermal thresholds, (b) correlate them with environmental history, algal symbiont distributions, land based pollution levels and site-specific management efforts. Do to so, we have developed an inexpensive, portable heat stress laboratory design, and a simple, short-term protocol to assess coral critical thermal tolerance. We are coupling our experiments in each site with outreach activities and citizen-scientist trainings, to inform the public about these issues and empower local institutions to add new sites and species to the Resistance Atlas. By assaying coral critical thermal tolerance at multiple sites across environmental and management gradients, we can (1) identify sites of particular resistance or susceptibility, (2) directly assess the correlations among thermal tolerance and environmental characteristics, and (3) establish a quantitative phenotypic dataset for investigating the transcriptomic/genomic basis of coral thermal tolerance.

C3.7  16:30  Assessing the vulnerability of the marine bird community in the western North Sea to climate change and other anthropogenic impacts . Burthe, SJ *, CEH; Wanless, S CEH; Newell, M CEH; Butler, A BIOSS; Daunt, F CEH;

Abstract: Ocean warming and anthropogenic activities are affecting marine top predators. Studies have focussed on impacts of single stressors on single species, yet understanding cumulative effects of stressors on communities is vital for conservation management. We studied a marine bird community (45 species) utilising the western North Sea for breeding, overwintering or migration between 1980 and 2011. Sea surface temperatures increased significantly over this period; simultaneously, the region has been subject to fishing pressure and a priority area for renewable energy developments. We used colony-based and at-sea data to assess relationships between SST and counts/demography for 25 species. For the remainder, we applied a qualitative approach using published population trends, climate relationships and foraging sensitivity. 53% of species showed negative relationships with SST. Climate vulnerability was combined with trends in counts and demography to give an index of population concern to future warming. 44% of species were classified as high or very high concern. Qualitative assessments of vulnerability to fisheries, pollutants, disturbance, marine renewables and climate found that 93% of species were vulnerable to ≥2 threats, and 58% to ≥4. This is the first, comprehensive assessment of multiple drivers on a marine bird community, and will act as a benchmark for conservation managers. The majority of species in this region face an uncertain future, potentially threatening the resilience of this important marine community.

C3.8  16:45  A manatee population in transition: Potential implications of a warming climate. Littles, CJ *, University of Florida; Pilyugin, S University of Florida; Frazer, T University of Florida;

Abstract: Endangered Florida manatees (Trichechus manatus latirostris) are sensitive to cool water temperatures and utilize natural warm-water springs as thermal refuge when coastal temperatures drop below 20°C. Manatee counts during winter aerial surveys along the northern Gulf coast of Florida are trending upward; a trajectory largely unexplained. Warmer winter temperatures may have resulted in increased yearly survival and contributed to the observed increase. We developed a stage-structured model to simulate the northwest subpopulation of manatees since 1990 and evaluated survivorship and reproduction parameters in light of the recent trend. Monthly aerial survey data were used to test and optimize model parameters. Our model estimated adult, juvenile and calf survival probabilities for the Northwest subpopulation of manatees at 0.969, 0.916, and 0.781, respectively, and the per capita reproduction rate at 0.14. These values are higher than previous estimates using alternative methods, but reflective of increased aerial counts. The proposed 3-stage model helps elucidate probable population metrics that underlie recent trends in aerial count data. Continued changes in regional climate-related variables and other environmental conditions will very likely impact future patterns of manatee distribution and observed abundance.

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