Trophic consequences of ocean acidification: Intertidal sea star predators and their grazer prey

人类产生的二氧化碳被吸收到世界海洋中，正在改变海水的化学成分，包括降低其PH值。这些变化统称为“海洋酸化”，预计将影响多种海洋生物。这个项目研究海洋pH值的变化如何影响动物的行为，从而影响物种之间的相互作用。它使用了一个案例研究系统，涉及海星捕食者、它们吃的蜗牛食草动物和后者吃的海藻。这些生物生活的岩岸栖息地一直受到关注，这项工作的新发现将进一步扩展本已庞大的海洋生态知识体系。该项目为研究生和本科生提供支持，包括来自附近社区大学的人数不足的学生。该项目是为当地K-12学校开发新的教育模块的基础。此外，调查结果还将通过使用短片纪录片，以及通过与政策、管理和行业团体建立的关系以及与媒体的联系向公众传达。然而，大多数关于这一主题的研究都考察了孤立运行的单个物种的影响，而对物种之间的相互作用没有进行充分的研究。这个项目通过考虑海洋酸化如何通过改变行为来改变捕食者和猎物之间的关系，来应对这一知识鸿沟。它通过四行调查，将海星、它们的腹足类食草动物猎物和被后者吃掉的马克藻作为一个模型系统。1)该项目利用针对高达16个离散的pH值水平的实验，研究了焦点分类群对海水化学变化的功能反应。这种实验设计对于识别非线性和临界点是必不可少的。2)该项目涉及直接和间接物种相互作用的消耗性和非消耗性组成部分。海洋酸化对这种联系的影响能力鲜为人知，更好地了解这一问题是公认的优先事项。3)该项目将受控的实验室实验与野外实验相结合，利用潮汐池塘及其独特的pH特征作为天然中温带。对海洋酸化效应的实地测试相对较少，迫切需要。4)最后的研究阶段在上述三个组成部分的基础上展开，以解决海洋酸化对多个在岩石潮间带系统中相互作用的额外类群的影响，以提供一个可能对未来的实验或建模有用的广泛数据库。

The absorption of human-produced carbon dioxide into the world's oceans is altering the chemistry of seawater, including decreasing its pH. Such changes, collectively called "ocean acidification", are expected to influence numerous types of sea creatures. This project examines how shifts in ocean pH affect animal behavior and thus interactions among species. It uses a case study system that involves sea star predators, snail grazers that they eat, and seaweeds consumed by the latter. The rocky-shore habitats where these organisms live have a long history of attention, and new findings from this work will further extend an already-large body of marine ecological knowledge. The project provides support for graduate and undergraduate students, including underrepresented students from a nearby community college. The project underpins the development of a new educational module for local K-12 schools. Findings will moreover be communicated to the public through the use of short film documentaries, as well as through established relationships with policy, management, and industry groups, and contacts with the media.Ocean acidification is a global-scale perturbation. Most research on the topic, however, has examined effects on single species operating in isolation, leaving interactions among species underexplored. This project confronts this knowledge gap by considering how ocean acidification may shift predator-prey relationships through altered behavior. It targets as a model system sea stars, their gastropod grazer prey, and macoalgae consumed by the latter, via four lines of inquiry. 1) The project examines the functional response of the focal taxa to altered seawater chemistry, using experiments that target up to 16 discrete levels of pH. This experimental design is essential for identifying nonlinearities and tipping points. 2) The project addresses both consumptive and non-consumptive components of direct and indirect species interactions. The capacity of ocean acidification to influence such links is poorly known, and better understanding of this issue is a recognized priority. 3) The project combines controlled laboratory experiments with field trials that exploit tide pools and their unique pH signatures as natural mesocosms. Field tests of ocean acidification effects are relatively rare and are sorely needed. 4) A final research phase expands upon the above three components to address effects of ocean acidification on multiple additional taxa that interact in rocky intertidal systems, to provide a broad database that may have utility for future experiments or modeling.