Development and application of CSI-AA biogeochemistry reconstructions in deep-sea corals to study decadal-centennial variability in the North Pacific

海洋生物生态系统的变化反映了海洋中的动态物理过程。这项研究的目的是利用新开发的、最先进的深海珊瑚化学成分分析，研究过去几个世纪浮游生物种群的地球化学变化和变化与环境变化的关系。该项目的重点是东北太平洋弧，其中包括阿拉斯加湾和加州海流系统（CCS）。这里的海表温度、海平面气压和沿海表面温度的仪器记录揭示了北太平洋海盆多年十年尺度变化的一致模式。资金支持一名研究生，一名博士后研究员的培训，并为UCSC本科生，社区大学生和高中生提供研究经验。该研究团队与UCSC西摩海洋发现中心合作，建立了一个新的永久性展览，突出深海珊瑚和与气候相关的生态系统变化。这项研究的中心目标是将来自深海蛋白质珊瑚的过去环境的高分辨率记录与新的化合物特异性氨基酸同位素（CSI-AA）测量相结合，以重建生物地球化学变化（例如，氮源）和基本浮游生物生态系统的变化跨越东北太平洋弧。研究小组将利用沉积物捕获器和活体采集的样本，更深入地了解出口生产与《珊瑚礁安全倡议-AA》基准值和深海蛋白质珊瑚记录的模式之间的联系，并建立这两者之间的明确联系。他们将运用这些知识，为东北太平洋生态系统在过去300-500年中变化的潜在机制提供新的见解。指导本研究的主要问题是：1）在太平洋年代际振荡之外，东北太平洋弧食物网是否存在结构性的、长期的、长期的变化？2)如果是的话，这些是如何反映在食物网底部的群落结构中的？以及3）在食物网的基础上，群落结构和硝酸盐来源如何响应这些变化而发生变化？

Oceanic biological-ecosystem variability reflects dynamic physical processes in the ocean. This research aims to use newly-developed, state-of-the-art analyses of the chemical composition of deep-sea corals to examine how biogeochemical changes and shifts in plankton populations are related to environmental changes over the past few centuries. The project focuses on the Northeast Pacific Arc, which includes the Gulf of Alaska and the California Current System (CCS). Here instrumental records of sea surface temperature, sea level pressure, and coastal surface temperature reveal a consistent pattern of multi-decadal-scale changes in the North Pacific Basin. Funding supports training of one graduate student, one postdoctoral fellow, and offers research experiences for UCSC undergraduates, community college students, and high school students. The research team has partnered with the UCSC Seymour Marine Discovery Center to establish a new permanent exhibit highlighting deep-sea corals and climate-related ecosystem change. The central goal of this research is to couple high resolution records of past environments derived from deep-sea proteinaceous corals together with new compound-specific amino acid isotope (CSI-AA) measurements to create reconstructions of both biogeochemical change (e.g., source of nitrogen) and basic plankton ecosystem shifts crossing the Northeast Pacific Arc. Using sediment trap and live-collected samples, the research team will develop a more intimate understanding of, and establish explicit links between export production and the CSI-AA baseline values and patterns recorded in proteinaceous deep-sea corals. They will apply this knowledge to provide new insight into the underlying mechanisms of North East Pacific ecosystem change over the last 300-500 years. Overarching questions guiding this research are: 1) Are there structural, secular, long-term changes in NE Pacific Arc food webs beyond the Pacific Decadal Oscillation?, 2) If yes, how are these reflected in the community structure at the base of the food web?, and 3) How has community structure and sources of nitrate at the base of the food-web shifted in response to these changes?