Changing Phytoplankton Trace Metal Requirements in a High CO2 Ocean

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。在过去的二十年里，铁和其他生物活性微量金属在构建海洋食物网和生物地球化学循环中的根本重要性已经实现。最近，在过去几年中，国际海洋科学界已开始动员起来，紧急努力了解人为二氧化碳增加和全球海洋酸化对生态系统的影响。该项目探讨这两个主要研究主题的交叉点，通过提出以下问题：海洋浮游植物的微量元素需求将如何变化，以应对未来大气pCO 2的增加？研究人员产生的初步数据表明，改变pCO 2确实可以深刻影响原核和真核浮游植物中Fe，Mo，Zn，Cd，Co和Mn的细胞配额。 微量金属作为酶促辅助因子在与CO2的可用性密切相关的过程中发挥着关键作用，如碳和氮固定，光合电子传递和营养物质获取。因此，重要的是开发方法来定量预测藻类金属需求将如何在未来迅速变化的海洋中变化。调查人员将采取三管齐下的方法来解决这个首要问题。实验室实验将测量的微量金属配额的稳态培养的关键浮游植物功能群，如硅藻，颗石藻，棕囊藻，固氮和微微蓝藻，同时改变二氧化碳分压都单独，以及与其他限制因素，如铁，温度和光。在南加州湾的实地工作将提供在一个季节性周期的自然浮游植物群落的微量金属化学计量的测量与pCO 2和其他环境变量-这一地区已经经历了一些最大的增加酸性涌上水沿着整个西海岸。这种观察和相关的研究将加上在南加州大学的卡塔利纳岛设施，其中相同的天然浮游植物群落的微量金属配额可以测量控制孵育条件下的二氧化碳分压变化的操纵实验。总之，这三种互补的方法将使研究人员能够在各种时间和空间尺度上确定植物毒素驱动的微量元素地球化学在未来高二氧化碳海洋中可能发生的变化。更广泛的影响包括为年轻的首席研究员Fu提供一个重要的职业里程碑的机会，她是南加州大学的少数民族女性研究员，以及通过夏季NSF-REU项目，南加州大学高级研究论文项目，以及与墨西哥裔和美洲原住民科学促进协会一起招募学生的新举措，为代表性不足的学生提供机会。该项目的社会和科学影响包括提供了一个新的视角，探讨海洋生物学和海洋地球化学对持续人为变化的综合反应，最终目标是更好地预测基本海洋资源的未来变化和对全球气候的潜在反馈。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Over the past two decades, the fundamental importance of iron and other bioactive trace metals in structuring marine food webs and biogeochemical cycles has been realized. Even more recently, over the past several years, the international ocean science community has begun to mobilize in an urgent effort to understand the ecosystem-level consequences of rising anthropogenic CO2 and acidification of the global ocean. This project examines the intersection of these two major research themes, by asking the question: How will the trace element requirements of marine phytoplankton change in response to future increases in atmospheric pCO2?Preliminary data generated by the investigators suggests that changing pCO2 can indeed profoundly affect the cellular quotas of Fe, Mo, Zn, Cd, Co and Mn in both prokaryotic and eukaryotic phytoplankton. Trace metals play critical roles as enzymatic co-factors for processes that are closely linked to the availability of CO2 such as carbon and nitrogen fixation, photosynthetic electron transport, and nutrient acquisition. Therefore, it is important to develop methods to quantitatively predict how algal metal requirements will change in tomorrow's rapidly changing ocean. The investigators will take a three-pronged approach to addressing this overarching question. Laboratory experiments will measure the trace metal quotas of steady-state cultures of key phytoplankton functional groups like diatoms, coccolithophores, Phaeocystis, and diazotrophic and pico-cyanobacteria while varying pCO2 both alone, and together with other limiting factors such as iron, temperature, and light. Field work in the Southern California bight will provide measurements in trace metal stoichiometry of natural phytoplankton communities over a seasonal cycle in relation to pCO2 and other environmental variables -- this region is already experiencing some of the largest increases in acidic upwelled water along the entire West Coast. This observational and correlative study will be coupled with manipulative experiments at the USC Catalina Island facility in which trace metal quotas of the same natural phytoplankton communities can be measured in relation to pCO2 shifts under controlled incubation conditions. Together, these three complementary approaches will enable the investigators to determine over a variety of temporal and spatial scales how phytoplankton-driven trace element biogeochemistry is likely to change in a future high-CO2 ocean.The broader impacts include providing an opportunity for a major career milestone for young lead investigator Fu, a female minority investigator at USC, as well as opportunities for under-represented students through the summer NSF-REU programs, senior research thesis programs at USC, and a new initiative for student recruitment with the Society for Advancement of Chicanos and Native Americans in Science. The societal and scientific impacts of this project include offering a novel perspective on the integrated responses of ocean biology and biogeochemistry to ongoing anthropogenic change, with the ultimate goal of better predicting future shifts in basic ocean resources and potential feedbacks to global climate.