Ocean Acidification: Collaborative Research: Quantifying the potential for biogeochemical feedbacks to create 'refugia' from ocean acidification on tropical coral reefs

不断上升的海面温度和海洋酸化（OA）可能会威胁到钙化生物构建碳酸盐礁的能力，但目前尚不清楚特定的珊瑚礁是否有能力承受全球变化。目前对OA对珊瑚礁影响的认识来自于单物种的实验室研究，主要集中在硬核珊瑚上。传统上，这些实验试图模拟静态的未来条件，假设沿海地区的情况与开阔的海洋表层水一样稳定，并且酸化的速度与之相同。基于这些过于简化的情景的预测是不现实的，因为许多底栖生物，包括钙化剂和初级生产者，在昼夜循环中显著改变了海水的总体碳酸盐化学。此外，最近在一些珊瑚礁中普遍存在的pH值极端波动表明，底栖生物可能已经适应了未来的碳酸盐环境。为了在珊瑚礁上寻找潜在的OA避难所，来自加利福尼亚大学圣地亚哥分校斯克里普斯海洋学研究所和拉蒙特多尔蒂地球观测站（哥伦比亚大学）的一个研究小组将在帕尔米拉环礁上进行一项独特的机械研究，帕尔米拉环礁是太平洋中部一个偏远的无人居住的岛屿，没有受到当地人类影响的退化。他们将探索从珊瑚礁底栖生物群落组合到上述海水化学的生物地球化学反馈的优势和控制，并通过实验确定这种自然波动如何影响关键分类群对OA的生理反应。具体而言，他们将：(1)将一种新的底栖生物通量技术紧密结合起来，该技术可以连续、高时间分辨率地测量净生态系统代谢率（生产和钙化），并进行高空间分辨率的底栖生物群落动态研究，以量化已知物种组合的反馈，以观察海水碳酸盐化学的自然时空变化；(2)利用小规模的普通花园CO2富集实验和实验室的生产力/呼吸分析，结合原位互惠移植实验，以经验量化二氧化碳浓度升高和/或波动对普通框架构建生物及其底栖竞争对手的生长、钙化和光生理的影响。这将使他们能够在没有其他混杂的人类影响的情况下，检查OA与自然环境中各种底栖珊瑚礁生物之间的耦合相互作用。更广泛的影响。海洋酸化预计将影响人类社会所依赖的许多生态系统产品和服务。具体来说，珊瑚礁提供的免受海岸侵蚀的物理保护将会减少，可能会加剧海平面上升的影响，OA对渔业和旅游业的影响尚待确定。一个中心目标是与当地社区和组织合作，更好地教育公众，让他们了解开放获取将如何影响人们、社会和他们使用的自然资源，并为个人提供工具，使他们能够成为解决方案的一部分。为此，研究小组与当地非营利公共广播服务机构圣迭戈KPBS建立了牢固的合作伙伴关系，以开发用于OA通信和教育的新产品。此外，他们将与SIO的Birch水族馆合作，开发一个展览，传达项目的成果。最后，该项目将直接培训实习生、学生和研究人员，并通过各种外展活动促进多样性，包括公开讲座、培训水族馆讲解员和开发基于网络的教育材料。

Rising sea surface temperatures and ocean acidification (OA) may threaten the ability of calcified organisms to build carbonate reefs, but it is unclear if particular reefs have the capacity to tolerate global change. Current understanding of the effects of OA on coral reefs originates from single-species laboratory studies largely focused on scleractinian corals. Traditionally, these experiments attempt to mimic static future conditions under the assumption that coastal regimes are as constant as -- and will acidify at the same rate as -- open ocean surface waters. Predictions based on these oversimplified scenarios are unrealistic because numerous benthic organisms, including calcifiers and primary producers, significantly alter the bulk seawater carbonate chemistry over a diurnal cycle. Further, the prevalence of recently appreciated extreme diel fluctuations in pH across some reefs suggests that benthic species may be acclimated to future carbonate conditions. To look for potential OA refugia on reefs, a research team from the Scripps Institute of Oceanography (University of California at San Diego) and the Lamont Dougherty Earth Observatory (Columbia University) will undertake a unique mechanistic study on Palmyra Atoll, a remote uninhabited island in the central Pacific that lacks degradation from local human influence. They will explore the strengths and controls of biogeochemical feedbacks from coral reef benthic community assemblages to the seawater chemistry above and experimentally determine how this natural fluctuation affects physiological responses of key taxa to OA. Specifically they will: (1) tightly integrate a novel benthic flux technique in situ that allows continuous, high-temporal resolution measurements of net ecosystem metabolic rates (production and calcification) with an ongoing high spatial resolution benthic community dynamics study to quantify feedbacks of known species assemblages to observed natural spatiotemporal variability in seawater carbonate chemistry; and (2) use small scale common garden CO2 enrichment experiments and productivity/respiration assays in the lab paired with reciprocal transplant experiments in situ to empirically quantify the effects of elevated and/or fluctuating pCO2 on growth, calcification and photophysiology of common framework building organisms and their benthic competitors. This should allow them to examine the coupled interactions between OA and diverse benthic coral reef organisms in their natural environment in the absence of other confounding human impacts. BROADER IMPACTS. Ocean acidification is expected to affect a number of ecosystem goods and services that human societies have come to depend on. Specifically, the physical protection that coral reefs provide from coastal erosion will be reduced, potentially exacerbating the effects of sea level rise, and the effects of OA on fisheries and tourism are yet to be determined. One central goal is to work with local communities and organizations to better educate the public about how OA will affect people, societies and the natural resources they use and to give individuals tools that can allow them to be part of the solution. To that end, the research team has established strong partnerships with a local non-profit public broadcasting service KPBS, San Diego to develop novel products for OA communication and education. Further, they will work with the Birch Aquarium at SIO to develop an exhibit that communicates the results of the project. Finally, the project will directly train interns, students and researchers and will promote diversity through a variety of outreach activities including public lectures, training of aquarium docents and the development of web-based educational materials.