Collaborative Research: Iron Regulation of the Food Quality of Phytoplankton In Acidified Eastern Boundary Upwelling Systems

在下一个世纪，东边界流上升流系统，这是家庭的一些主要渔业，支持世界各地的人类，预计将经历极端酸化（pH值下降到7.3或更低），因为增加大气中的二氧化碳。 可能会对微量金属（特别是铁）和氮的生物利用度产生影响，因此预计浮游植物的物种组成和生理也会发生变化。 海洋酸化的一个未充分研究的方面是它对浮游植物脂质和多不饱和脂肪酸（PUFA）的影响，如二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）以及其他必需脂肪酸（EFA），这些脂肪酸是更高营养水平所依赖的。在这个项目中，来自旧金山弗朗西斯科州立大学、夏威夷大学、和缅因州大学将研究极端海洋酸化（OA）的影响下，铁充满和耗尽上升流条件下的物种组成的变化，总脂质生产，和具体生产的多不饱和脂肪酸。 有两个指导性假设：（1）极端海洋酸化将通过碳吸收和氮吸收减少之间的不平衡增加浮游植物的脂质合成和EFA生产;以及（2）在自然上升流区，极端的海洋酸化会改变PUFA和EFA的数量和组成，这可能是由于酸化海水对细胞生理的直接影响，也可能是由于浮游植物群落的显著变化混合物. 目前的Fe-充满和Fe-耗尽上升流区在加州上升流区将进行调查，以说明这些影响。 该团队将使用受控的实验室单克隆，半连续培养实验，将代表性的沿海浮游植物分离物置于不同的pH值和铁的可用性下，以表征极端pH环境条件下的耐受性/成功率，并量化细胞对组合压力源的生理反应。 在项目的第三年，将研究社区一级对同一系列压力源的反应。 由于海洋渔业的全球重要性以及对海洋酸化潜在威胁的了解尚不多，本研究的主题跨越了各种学科，机构，学术政府和国家边界。 所有三个参与机构的研究人员将领导各种公共教育推广活动，以造福K-12学生和整个社会。 研究生和本科生也将是研究工作的重要组成部分。

Within the next century, Eastern Boundary Current upwelling systems, which are home to some of the major fisheries that support humans worldwide, are expected to undergo extreme acidification (pH falling to 7.3 or lower) because of increasing atmospheric CO2. Impacts on trace metal (especially iron) and nitrogen bioavailability are likely, and consequently changes in phytoplankton species composition and physiology are also to be expected. One understudied aspect of ocean acidification is its impact on the production of phytoplankton lipids and polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and other essential fatty acids (EFA) upon which higher trophic levels depend.In this project a research team from San Francisco State University, University of Hawaii, and University of Maine will study the effect of extreme ocean acidification (OA) under iron replete and deplete upwelling conditions in regard to changes in species composition, total lipid production, and the specific production of PUFAs. There are two guiding hypotheses: (1) Extreme ocean acidification will increase lipid synthesis and EFA production in phytoplankton through the imbalance between carbon uptake and decreased nitrogen uptake; and (2) Extreme ocean acidification in natural upwelling regions will change the amount and composition of PUFA and EFA produced due either the direct effects of acidified seawater on cell physiology or to marked shifts in phytoplankton community composition. Current Fe-replete and Fe-deplete upwelling zones in the California upwelling region will be investigated to illustrate these impacts. The team will use controlled laboratory monoclonal, semi-continuous culture experiments to subject representative coastal phytoplankton isolates to varying pH and Fe availability to characterize tolerance/success under extreme pH environmental conditions and to quantify cellular physiological response to the combined stressors. In the third year of the project, community-level responses to the same set of stressors will be studied.Broader Impacts: Because of the global importance of marine fisheries and the as-yet modest understanding of the potential threats of ocean acidification, the topic of this study spans a variety of disciplinary, institutional, academic-government, and national boundaries. Researchers at all three participating institution will lead a variety of public educational outreach activities for the benefit of K-12 students and for society at-large. Graduate and undergraduate students will also be an important part of the research effort.