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Program |
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Special Session 1: Ecosystem under multiple stressors |
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Does heavy metal exposure decrease thermal tolerance of crabs? A case study from the subtropical mangroves of Hong Kong
Wednesday 11th @ 1138-1155
Multi-function Hall
Stefano Cannicci* , Swire Institute of Marine Sciences and School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
Joao Marcelo Silva, Instituto do Mar, Universidade Federal de Sao Paulo, Brazil
Rebekah J Butler, Swire Institute of Marine Sciences and School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
Ronaldo Christofoletti, Instituto do Mar, Universidade Federal de Sao Paulo, Brazil
Gray A. Williams, Swire Institute of Marine Sciences and School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
Presenter Email: cannicci@hku.hk
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| Mangrove forests are threatened by a number of direct and indirect anthropogenic stressors. Although mangroves are not generally thought to be vulnerable to climate change, the unprecedented combination of various human impacts on mangrove forests may undermine their resilience to future climatic change. A major cause of mangrove loss within the last 50 years is related to the increasing volume of chemical-contaminated runoff from urban, industrial and agricultural areas. Mangroves acts as physical and biochemical barriers to contaminants and it is well known that their sediments sequester heavy metals.
Despite a number of studies focusing on the concentration of heavy metals in mangrove sediments and plant tissues, our understanding about their bioavailability and impact on the biology of the mangrove fauna is still preliminary. In South China, studies mainly focused on heavy metal presence in bivalves and gastropods tissues, often ignoring the effects on crab communities, which actually are of paramount importance for the overall mangrove ecosystem functioning. Heavy metal pollution can enhance the vulnerability of populations to climate change by affecting their genetic diversity and narrowing their specific thermal windows , ultimately affecting their physiological performance.
In the present study, we investigated the influence of heavy metal bioaccumulation on the thermal performance of mangrove crabs exposed to heavily and lightly metal-impacted mangroves in Hong Kong. Respiratory and circulatory (heart rate) metrics were recorded in vivo using non-invasive techniques. Our data show that crabs bioaccumulate heavy metals through the food web and that tissue concentrations affect their physiological performance. The results are discussed in the light of the acclimation ability of semi-terrestrial mangrove crabs to cope with climate change in a multiple-stressor scenario such as the mangroves of South China. |
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