EAPSI: Understanding the response of a natural system to long-term acidification using Sydney rock oysters and mud crabs as a model predator-prey system

海洋酸化是由于二氧化碳(CO2)的吸收而导致海洋pH的逐渐下降，预计它将对牡蛎等钙化生物的外壳形成产生不利影响。应探讨海洋酸化对多种相互作用物种的影响，以了解对生态系统动力学的影响。澳大利亚悉尼附近的红树林河口经历了酸性土壤径流，为研究海洋酸化及其对生态系统的影响提供了一个天然实验室。这项研究将通过笼养实验和实验室实验研究海洋酸化对螃蟹-牡蛎捕食者-猎物系统的影响，实验使用的是世代暴露在酸化环境中的天然牡蛎种群。这项研究将与澳大利亚悉尼麦格理大学的红树林无脊椎动物群落生态学专家梅勒妮·毕晓普博士合作进行。在源头河口，生长在酸化或正常pH条件下的悉尼岩牡蛎(Saccostrea Gregata)将与泥蟹捕食性动物(Scylla Serrata)一起关在酸性水和正常pH水中的笼子中，为期一周。牡蛎死亡率、泥蟹的存在和pH值之间的关系将使用线性模型进行检验。在另一项单独的实验室实验中，来自酸化和正常pH值地点的牡蛎将暴露在泥蟹的捕食下，捕食者行为的视频将被用来计算处理时间(捕食者花在操纵或吃掉猎物上的时间)。酸化对处理时间和牡蛎死亡率的影响将使用方差分析进行检验。这项研究扩展了海洋酸化研究，考察了全球变化对两个具有重要商业意义的物种之间相互作用的影响，并使用了世代适应自然界长期酸化的牡蛎。该NSF EAPSI奖是与澳大利亚科学院合作资助的。

Ocean acidification is the gradual decrease in ocean pH as a result of carbon dioxide (CO2) uptake, and it is expected to have detrimental effects on the shell formation of calcified organisms such as oysters. The effect of ocean acidification on multiple interacting species should be explored to understand impacts on ecosystem dynamics. Mangrove estuaries experiencing acidic soil runoff near Sydney, Australia provide a natural laboratory for the study of ocean acidification and its effects on the ecosystem. This study will examine the effect of ocean acidification on a crab-oyster predator-prey system through a caging experiment and a laboratory experiment using a natural population of oysters that have been exposed to acidification for generations. This research will be conducted in collaboration with Dr. Melanie Bishop, an expert on community ecology of mangrove invertebrates, at Macquarie University in Sydney, Australia. In the source estuaries, Sydney rock oysters (Saccostrea glomerata) grown in either acidified or normal pH conditions will be enclosed in cages with mud crab predators (Scylla serrata) in both acidified and normal pH water for one week. The relationship between oyster mortality, the presence of mud crabs, and pH will be examined using linear models. In a separate laboratory experiment, oysters from acidified and normal pH sites will be exposed to mud crab predation, and video of predator behavior will be used to calculate handling time (the time a predator spends manipulating or eating a prey item). The effect of acidification on handling time and oyster mortality will be examined using ANOVAs. This study expands upon ocean acidification research by examining the effect of global change on interactions between two commercially important species, and by using oysters that have had generations to adapt to long-term acidification in nature. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.