Effects of ocean acidification on benthic marine species and ecosystems

由于人为二氧化碳被海洋吸收，它改变了碳酸盐化学，并导致pH值和碳酸盐离子有效性的降低。这一过程被称为海洋酸化(OA)，将导致海洋pH值在本世纪末之前达到数百万年来未曾见过的水平。由于可能导致大规模的生态变化，包括人口崩溃、食物网中断和生态系统功能丧失，海洋生态系统最大的威胁就是海洋生态系统。迄今为止，记录在案的酸化影响包括幼虫发育受阻、生长减慢、贝壳和骨骼溶解以及直接死亡。尽管人们越来越清楚地描述了海洋酸化对个体表现的影响，但我们目前无法预测海洋酸化将如何影响人们最关心的事情，如可收获的人口数量和生物多样性。 我的研究计划集中在三个主要领域，其中关于OA影响的信息特别有限：1)酸化将如何推动种群增长或下降的变化，2)酸化将通过物种间相互作用的变化产生哪些重要的间接影响，以及3)这些反应的总和将如何改变整个生态系统？为了解决这些问题，我的研究小组正在使用微藻、海藻和无脊椎动物研究系统在实验室和野外操纵二氧化碳浓度。我们将确定OA对种群增长的变化(例如，在经济上重要的海胆)、对竞争和捕食等过程以及对生物多样性、生产力和其他生态系统属性的影响。我们的目标是了解变化的机制(例如，食物链中关键物种的损失)，从而为加拿大的保护和管理提供关键信息。此外，通过对不同类型的生物(植物和动物，钙化物种和未钙化物种)进行比较，我们将把对海洋酸化的全面生态反应置于预测框架内，从根本上推进全球变化生态学领域。

As anthropogenic carbon dioxide is absorbed by the oceans, it alters carbonate chemistry and leads to reductions in pH and carbonate ion availability. This process, know as ocean acidification (OA), will result in oceanic pH levels not seen in many millions of years being reached well before the end of this century. Because massive ecological changes, including population collapses, disruption of food webs, and loss of ecosystem function, are likely to result, OA is considered to be the single greatest threat to marine ecosystems. To date, documented effects of acidification include impairment of larval development, reductions in growth, dissolution of shells and skeletons, and direct mortality. Although effects of OA on individual performance are increasingly well described, we cannot currently predict how ocean acidification will affect the things that people care about the most, like harvestable population size and biodiversity. My research program focuses on three main areas in which information on OA impacts is particularly limited: 1) how will acidification drive changes in population growth or decline, 2) what important indirect effects of acidification will arise via changes in interactions among species, and 3) how will the sum of these responses alter entire ecosystems? To address these questions, my research group is manipulating carbon dioxide concentrations in the laboratory and in the field using microalgal, seaweed, and invertebrate study systems. We will determine the impacts of OA on changes in population growth (e.g., in economically important sea urchins), on processes such as competition and predation, and on biodiversity, productivity, and other ecosystem attributes. Our goal is to understand the mechanisms of change (e.g., loss of key species in a food web) and thereby provide key information for conservation and management in Canada. Furthermore, by making comparisons across different types of organisms (plants vs. animals, calcified vs. uncalcified species), we will fundamentally advance the field of global change ecology by placing the full range of ecological responses to ocean acidification within a predictive framework.