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

海洋表面温度上升和海洋酸化（OA）可能会威胁钙化生物建造碳酸盐珊瑚礁的能力，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主要集中在石珊瑚的单物种实验室研究。 传统上，这些实验试图模拟静态的未来条件下，假设沿海地区是恒定的-并将酸化的速度与-开放的海洋表面沃茨。 基于这些过于简化的假设的预测是不现实的，因为许多底栖生物，包括钙化者和初级生产者，在一个昼夜周期内显著改变了大量海水碳酸盐的化学性质。 此外，最近发现的一些珊瑚礁pH值极端昼夜波动的普遍性表明，底栖物种可能会适应未来的碳酸盐条件。 为了在珊瑚礁上寻找潜在的OA避难所，来自斯克里普斯海洋学研究所（位于圣地亚哥的加州大学）和拉蒙道格拉斯地球观测站（哥伦比亚大学）的一个研究小组将对帕尔米拉环礁进行一项独特的机械研究，巴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群落组合到上述海水化学的生物地球化学反馈的强度和控制，并通过实验确定这种自然波动如何影响关键类群对OA的生理反应。 具体来说，他们将：（1）紧密结合一种新的原位底栖通量技术，可对净生态系统代谢率进行连续、高时间分辨率的测量（生产和钙化），同时正在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对观测到的海水碳酸盐化学性质的自然时空变化的反馈;和（2）在实验室中使用小规模的普通花园CO2富集实验和生产力/呼吸测定，与原位相互移植实验配对，以经验性地量化升高和/或波动的pCO 2对生长的影响，常见的骨架建筑生物及其底栖竞争者的钙化和生物生理学。 这将使他们能够在没有其他人为影响的情况下，研究有机农业与自然环境中各种底栖珊瑚礁生物之间的相互作用。 更广泛的影响。 海洋酸化预计将影响人类社会所依赖的一些生态系统产品和服务，具体而言，珊瑚礁提供的防止海岸侵蚀的实际保护将减少，可能加剧海平面上升的影响，有机农业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OA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，研究团队与圣地亚哥当地的非营利公共广播服务KPBS建立了强有力的合作伙伴关系，为OA通信和教育开发新产品。 此外，他们将与SIO的Birch水族馆合作，开发一个传达项目成果的展览。 最后，该项目将直接培训实习生、学生和研究人员，并将通过各种外联活动促进多样性，包括公开讲座、培训水族馆讲解员和编制网上教材。

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.