Ocean Acidification: Physiological and genetic responses of the deep-water coral, Lophelia pertusa, to ongoing ocean acidification in the Gulf of Mexico

墨西哥湾的深水生态系统受到海洋酸化的持续威胁。深水珊瑚将是最先感受到这一过程影响的珊瑚之一，尤其是由文石形成骨架的深水硬壳动物。文石饱和层（文石未饱和的深度）的持续浅滩化将在不久的将来使许多已知的和尚未发现的深水珊瑚处于危险之中。世界海洋中最常见的形成深水框架的硬壳藻是Lophelia pertusa。这种珊瑚在北大西洋最为丰富，那里文石饱和度相对较高，但它也在墨西哥湾300至600米深度之间形成了广泛的珊瑚礁结构，在那里文石饱和度以前是未知的。初步数据表明，该深度范围内的pH值在7.85 ~ 8.03之间，文石饱和状态一般在1.28 ~ 1.69之间。这是对墨西哥湾深处文石饱和度的首次测量，也是迄今为止在任何水域、任何深度的框架形成珊瑚中文石饱和度最低的记录之一。该项目将结合实验室实验、严格的海洋学测量、最新的基因组和转录组测序平台、定量PCR和酶分析，研究海洋酸化对L. pertusa的影响，以研究与碳酸盐化学差异相关的珊瑚基因表达和酶活性的变化。将在文石饱和度为1.45和0.75的情况下进行短期和长期实验室实验，并监测珊瑚的有机体（如存活率和钙化率）和遗传（如转录丰度）反应。将提取基因组DNA和RNA，纯化总mRNA，并使用454和Illumina测序技术组合生成转录组的全面定量图谱。将针对钙化途径中的关键基因以及其他差异表达基因进行特异性qPCR检测，以验证Illumina测序结果。在一次研究巡航中，L. pertusa将沿着碳酸盐化学的自然梯度取样（保存在深度），并包括在Illumina测序和qPCR分析中。水样将在珊瑚收集区附近的水下放置的皮肤瓶，以及在地点上方的水柱的CTD模型中获取。将分析水样的pH值、碱度、硝酸盐和可溶性活性磷。这些数据将与历史数据相结合，在一个模型中用于预测文石的饱和状态。知识价值：该项目将为墨西哥湾一种具有重要生态意义和受到人为威胁的深水珊瑚提供新的生理和遗传数据。pi已经开发了一个实验系统，提供了受控条件来测试文石饱和状态对硬骨细胞钙化率的影响，并随后确定参与降低pH和文石饱和状态反应的候选基因和途径。长期和群体抽样实验将提供额外的转录组学数据，并专门研究候选基因的表达。这些结果将有助于我们理解硬核虫适应和适应低pH、碱度和文石饱和状态的手段。此外，研究人员将继续对墨西哥湾的碳酸盐系统进行时间序列的海洋学测量，这将允许将这一重要水体纳入过去和未来海洋酸化情景的模型中。更广泛的影响：将墨西哥湾正在进行的海洋酸化研究与珊瑚对低饱和状态的生理和遗传反应相结合的结果将在会议、研讨会上发表，并发表在高影响力和开放获取的出版物上。原始和处理过的数据将在现有数据库中提供，包括NCBI（遗传和基因组数据），并通过生物和化学海洋学数据管理办公室（BCO-DMO）提供。所有项目数据也将通过链接到每个pi网站的本地ftp服务器提供。这些私人学院致力于将代表性不足的少数族裔纳入他们的研究，并在天普大学（Temple University）指导本科生方面有着良好的记录。天普大学是美国最多元化的院校之一。一个为期两天的研讨会将由私人学院领导，由海洋泉湾沿岸研究实验室的谢里亚·布朗博士协调，届时将有20名墨西哥湾沿岸高中教师参加，其中也包括来自天普大学的学生。MS为教师提供所需的背景和材料，以便将基于这些结果的课程直接引入他们的课堂。一名高中老师也将参加这次巡游。通过这些努力，研究人员希望提高公众对海洋酸化问题的认识，提高对美国水域深水珊瑚群落存在的认识水平，并激励下一代科学家。

The Gulf of Mexico deep water ecosystems are threatened by the persistent threat of ocean acidification. Deep-water corals will be among the first to feel the effects of this process, in particular the deep-water scleractinians that form their skeleton from aragonite. The continued shoaling of the aragonite saturation horizon (the depth below which aragonite is undersaturated) will place many of the known, and as yet undiscovered, deep-water corals at risk in the very near future. The most common deep-water framework-forming scleractinian in the world's oceans is Lophelia pertusa. This coral is most abundant in the North Atlantic, where aragonite saturation states are relatively high, but it also creates extensive reef structures between 300 and 600 m depth in the Gulf of Mexico where aragonite saturation states were previously unknown. Preliminary data indicate that pH at this depth range is between 7.85 and 8.03, and the aragonite saturation state is typically between 1.28 and 1.69. These are the first measurements of aragonite saturation state for the deep Gulf of Mexico, and are among the lowest Aragonite saturation state yet recorded for framework-forming corals in any body of water, at any depth. This project will examine the effects of ocean acidification on L. pertusa, combining laboratory experiments, rigorous oceanographic measurements, the latest genome and transcriptome sequencing platforms, and quantitative PCR and enzyme assays to examine changes in coral gene expression and enzyme activity related to differences in carbonate chemistry. Short-term and long-term laboratory experiments will be performed at Aragonite saturation state of 1.45 and 0.75 and the organismal (e.g., survivorship and calcification rate) and genetic (e.g., transcript abundance) responses of the coral will be monitored. Genomic DNA and RNA will be extracted, total mRNA purified, and comprehensive and quantitative profiles of the transcriptome generated using a combination of 454 and Illumina sequencing technologies. Key genes in the calcification pathways as well as other differentially expressed genes will be targeted for specific qPCR assays to verify the Illumina sequencing results. On a research cruise, L. pertusa will be sampled (preserved at depth) along a natural gradient in carbonate chemistry, and included in the Illumina sequencing and qPCR assays. Water samples will be obtained by submersible-deployed niskin bottles adjacent to the coral collections as well as CTD casts of the water column overlying the sites. Water samples will be analyzed for pH, alkalinity, nitrates and soluble reactive phosphorus. These will be used in combination with historical data in a model to hindcast Aragonite saturation state.Intellectual Merit: This project will provide new physiological and genetic data on an ecologically-significant and anthropogenically-threatened deepwater coral in the Gulf of Mexico. An experimental system, already developed by the PIs, offers controlled conditions to test the effect of Aragonite saturation state on calcification rates in scleractinians and, subsequently, to identify candidate genes and pathways involved in the response to reduced pH and Aragonite saturation state. Both long-term and population sampling experiments will provide additional transcriptomic data and specifically investigate the expression of the candidate genes. These results will contribute to our understanding of the means by which scleractinians may acclimate and acclimatize to low pH, alkalinity, and Aragonite saturation state. Furthermore, the investigators will continue a time series of oceanographic measurements of the carbonate system in the Gulf of Mexico, which will allow the inclusion of this significant body of water in models of past and future ocean acidification scenarios.Broader Impacts: Results that combine the study of ongoing ocean acidification in the Gulf of Mexico with the physiological and genetic responses of the corals to low saturation state will be presented at conferences, seminars, and published in high-impact and open-access publications. Raw and processed data will be made available in existing databases including NCBI (genetic and genomic data), and through the Biological and Chemical Oceanography Data Management Office (BCO-DMO). All project data will also be made available via a local ftp server linked to each of the PIs websites. The PIs are committed to the inclusion of under-represented minorities in their research, and have a proven record of mentoring undergraduates at Temple University, one of the most diverse institutions in the U.S. A two-day workshop for 20 Gulf Coast high school teachers, and also including students from Temple, will be led by the PIs and coordinated by Dr. Shelia Brown at the Gulf Coast Research Lab in Ocean Springs, MS to provide teachers with the background and materials needed to bring curricula based on these results directly into their classrooms. A high school teacher will also participate in the cruise. Through these efforts, the investigators hope to raise public consciousness of the issue of ocean acidification, increase the level of awareness of the presence of deep-water coral communities in U.S. waters, and to inspire the next generation of scientists.