Department of Earth and Marine Sciences (DiSTeM), University of Palermo, Palermo, Italy; National Inter-University Consortium for Marine Sciences (CoNISMa), Rome, Italy.
Department of Earth and Marine Sciences (DiSTeM), University of Palermo, Palermo, Italy.
Sci Total Environ. 2019 Jun 1;667:41-48. doi: 10.1016/j.scitotenv.2019.02.391. Epub 2019 Feb 26.
Experiments have shown that increasing dissolved CO concentrations (i.e. Ocean Acidification, OA) in marine ecosystems may act as nutrient for primary producers (e.g. fleshy algae) or a stressor for calcifying species (e.g., coralline algae, corals, molluscs). For the first time, rapid habitat dominance shifts and altered competitive replacement from a reef-forming to a non-reef-forming biogenic habitat were documented over one-year exposure to low pH/high CO through a transplant experiment off Vulcano Island CO seeps (NE Sicily, Italy). Ocean acidification decreased vermetid reefs complexity via a reduction in the reef-building species density, boosted canopy macroalgae and led to changes in composition, structure and functional diversity of the associated benthic assemblages. OA effects on invertebrate richness and abundance were nonlinear, being maximal at intermediate complexity levels of vermetid reefs and canopy forming algae. Abundance of higher order consumers (e.g. carnivores, suspension feeders) decreased under elevated CO levels. Herbivores were non-linearly related to OA conditions, with increasing competitive release only of minor intertidal grazers (e.g. amphipods) under elevated CO levels. Our results support the dual role of CO (as a stressor and as a resource) in disrupting the state of rocky shore communities, and raise specific concerns about the future of intertidal reef ecosystem under increasing CO emissions. We contribute to inform predictions of the complex and nonlinear community effects of OA on biogenic habitats, but at the same time encourage the use of multiple natural CO gradients in providing quantitative data on changing community responses to long-term CO exposure.
实验表明，增加海洋生态系统中溶解二氧化碳的浓度（即海洋酸化，OA）可能成为初级生产者（如肉质藻类）的营养物质，或成为钙化物种（如珊瑚藻、珊瑚、软体动物）的应激源。首次通过在 Vulcano 岛 CO 渗漏（意大利西西里岛东北部）进行的移植实验，记录了在一年的时间里，由于低 pH/高 CO 暴露，从造礁生物生境向非造礁生物生境的快速栖息地优势转变和竞争替代。海洋酸化通过降低造礁物种密度来减少贻贝礁的复杂性，促进了冠层大型藻类的生长，并导致相关底栖生物群落的组成、结构和功能多样性发生变化。OA 对无脊椎动物丰富度和丰度的影响是非线性的，在贻贝礁和冠层形成藻类的中等复杂水平下达到最大值。在高 CO 水平下，较高等级消费者（如肉食动物、悬浮食者）的丰度下降。在高 CO 水平下，食草动物与 OA 条件呈非线性关系，只有次要的潮间带食草动物（如桡足类）的竞争释放增加。我们的结果支持 CO 的双重作用（既是应激源又是资源）在破坏岩石海岸群落的状态，并对 CO 排放增加下潮间带礁生态系统的未来提出了具体的担忧。我们有助于预测 OA 对生物生境的复杂和非线性群落效应，但同时鼓励使用多个自然 CO 梯度来提供关于长期 CO 暴露下群落对变化的反应的定量数据。
