Ocean Acidification Category 2: Collaborative Research - Development of geochemical proxies to evaluate larval pH-exposure history

学术价值：该项目将在连通性生态学(Levin在SIO)、金属同位素地球化学(Anbar和Gordon在亚利桑那州立大学)和古气候学(在亚利桑那州立大学Herrmann)之间建立新的跨学科伙伴关系，以确定新的海洋酸化指标，可用于评估生物体内的pH值暴露，并有可能解释地质记录。研究人员假设，幼体碳酸钙的同位素组成反映了海洋酸化导致的海水化学变化，在某些情况下，还伴随着氧气水平的下降。这两个参数在现代和过去海洋中的很大程度上一致变化(因此具有共同影响)，以及它们可能在多大程度上被人为的二氧化碳输入分离，值得相当关注。因此，pH和氧气在替代物开发中的整合将是一个重要的进展。该项目的重点是通过替代开发来确定处于幼虫状态的生物的pH暴露历史，并将集中在钙、硼和铀同位素以及多元素指纹上。在这个项目中，调查人员将瞄准开阔的海岸、前湾和后海湾的贻贝物种，每个物种都在不同的pH条件下自然生活，以及从开放货架上捕获的密封市场鱿鱼幼体的雕像。已知的pH、氧气和温度暴露史的幼虫将通过(1)操纵pH和氧气的实验室幼虫饲养实验和(2)将实验室产卵的幼虫原位种植到正在监测pH、T和氧气的现有系泊处获得。分析将使用SIMS(针对del 11B)、多收集器(针对del 44Ca、del 238U)和激光消融电感耦合等离子体质谱(针对B、铜、U、铅、钼以及一套额外的pH和氧化还原敏感的痕量元素)。多变量统计工具将定义检测pH诱导的特征和确定物种或分类群特定的生命效应的能力。研究人员正在探索未在酸化地球化学背景下测试的无脊椎动物幼虫的替代品。以幼虫为目标至关重要，因为许多海洋生物产生幼体碳酸盐结构，而这些阶段可能最受海洋酸化的影响。幼虫壳和雄石在补充后的保留可能最终允许我们测试幼虫暴露在pH和O2环境中对生存和种群持久性的重要性。通过地球化学指标评估过去暴露的能力将提供有关相对pH容忍度和生态系统水平变化的信息，以应对海洋的变化--S碳酸盐化学。广泛影响：该项目将：(1)动员年轻科学家开展新的合作，(2)通过加州大学夏季多样性项目吸引代表性不足的学生，(3)通过加州大学圣地亚哥分校全球变化、海洋科学与社会项目的IGERT课程，以及通过莱文、安巴和赫尔曼教授的课程，向学生传播科学。将生态学成果转化为海洋地球化学和古气候学领域(以及相关领域)，将为未来的合作和进展提供种子。

Intellectual merit: This project will develop a new interdisciplinary partnership between connectivity ecology (Levin at SIO), metal isotope geochemistry (Anbar and Gordon at ASU), and paleoclimatology (Herrmann at ASU) to identify new proxies for ocean acidification that can be used to assess pH exposures in living organisms and, potentially to interpret the geologic record. The investigators hypothesize that the isotopic composition of larval calcium carbonates reflects changes in seawater chemistry driven by ocean acidification and, in some instances, with associated decline in oxygen levels. The large extent to which these two parameters vary in concert in the modern and past ocean (and thus have joint influence), and the extent to which they may be uncoupled by anthropogenic CO2 inputs, merits considerable attention. Thus, the integration of pH and oxygen in proxy development would be an important advance.The focus of this project is on proxy development to determine pH exposure history for living organisms in their larval state, and will center on calcium, boron, and uranium isotopes as well as multi-elemental fingerprints. For this project, the investigators will target open coast, front bay and backbay mytilid mussel species, each living naturally under a different pH regime, and statoliths of encapsulated market squid larvae from the open shelf. Larvae with known pH, oxygen and temperature exposure histories will be obtained from (1) laboratory larval rearing experiments that manipulate pH and oxygen and (2) in situ out planting of lab-spawned larvae in larval homes onto existing moorings where pH, T and oxygen are being monitored. Analyses will employ SIMS (for del 11B), multicollector (for del 44Ca, del 238 U), and laser ablation ICP-MS (targeting B, Cu, U, Pb, Mo, and a suite of additional pH- and redox-sensitive trace elements). Multivariate statistical tools will define ability to detect pH-induced signatures and to determine species or taxon-specific vital effects. The investigators are exploring proxies for invertebrate larvae that are untested in the context of acidification geochemistry. Targeting larvae is critical as many marine organisms produce larval carbonate structures and these stages may be most affected by ocean acidification. The retention of larval shell and statoliths after recruitment may ultimately allow us to test the importance of larval pH and O2 exposure to survival and population persistence. An ability to assess past exposures through geochemical proxies will provide information about relative pH tolerances and ecosystem-level change in response to changes in the ocean¡¦s carbonate chemistry.Broader impacts: This project will: (1) engaging young scientists in new collaborations (2) involving underrepresented students through UC summer diversity programs and (3) conveying the science to students via UCSD IGERT courses in the program Global Change, Marine Science and Society, as well as via courses taught by Levin, Anbar and Herrmann. Translation of ecological results to the fields of marine geochemistry and paleoclimatology (and back) will provide the seed for future collaboration and advances.