Accomplishment Based Renewal: An iron limitation mosaic within the central California Current System

基于成就的更新：加州中部洋流系统内的铁限制马赛克

• 批准号: 1259776
• 负责人: Kenneth Bruland
• 金额: $ 60.2万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1259776&HistoricalAwards=false
• 关键词: Accomplishment; Based; Renewal; iron; limitation

Eastern boundary upwelling systems have long been recognized for their high phytoplankton productivity. Carr and Kearns (2003), in a detailed comparison of eastern boundary current systems, reported that biomass sustained by a given macronutrient concentration in Atlantic eastern boundary current systems was twice as large as those systems in the Pacific. The authors concluded "It is not clear whether the apparent difference in biomass supported by available nutrients is due to differences in the efficiency of the phytoplankton community, perhaps related to the availability of iron, or to grazing pressure." They suggested that the width of the shelf might be considered a proxy for the benthic availability of iron. The lowest biomass for a given macronutrient concentration was in the Peru-Humboldt Current and in the northern California region of the California Current System, both areas with low dust inputs and a relatively narrow shelf. In this Accomplishment Based Renewal project, a marine trace metal geochemist at the University of California - Santa Cruz and his students and colleagues will continue a decades-old quest to understand the role of iron in the central California Current System (cCCS). Field efforts will combine continuous underway iron and nutrient data in surface waters and a series of vertical profiles. The focus will include three regions within the cCCS: a variety of active Fe-replete and Fe-deplete coastal upwelling regimes, the eddy-rich California Current transition zone that is Fe-limited and has elevated nitrate but relatively low and uniform chlorophyll concentrations, and the offshore, oligotrophic California Current. They will map surface and depth distributions of Fe and other micro- and macronutrients. There are four specific goals dealing with characterizing the organic Fe(III)-binding organic ligands, determining Fe(II) and Fe(III) concentrations in hypoxic waters over the shelf, examining the exchange between particulate and dissolved forms of Fe, and studying the roles of eddies in the eddy-rich transition waters of the cCCS. Broader ImpactsDirect Benefits to Science: There is a great deal of interest in the CCS because of its importance in terms of phytoplankton productivity and the support of higher trophic levels. Until now, the emphasis in studies of the CCS has been on relationships between physics and biology. This study will insert the important role of micronutrient chemistry into the picture. It will also serve an important role in securing ship time in advance and providing logistical support for other collaborative studies. This is extremely valuable and cost effective for collaborating scientists since with the hydrography, nutrient and trace metal data provided, they can focus on their complimentary research efforts.Outreach and Education: The project will provide funding for two current graduate students at UCSC, where they will also receive course training in a curriculum that includes i) scientific communication, ii) careers in marine science, and iii) grant writing. A broader impact goal of this project is to facilitate teaching and learning on marine science-related topics through translating research objectives into widely distributed educational materials for classroom use. To accomplish this, the team will partner with the Seymour Discovery Center at the Long Marine Lab, UCSC. The Discovery Center receives 14,000 visitors each year, and the project will provide funds to develop an interactive display on limiting nutrients and phytoplankton bloom development in the CCS.

东部边界上升流系统长期以来被认为具有较高的浮游植物生产力。卡尔和卡恩斯（2003年）在对东部边界洋流系统进行详细比较时报告说，大西洋东部边界洋流系统中由特定常量营养素浓度维持的生物量是太平洋东部边界洋流系统的两倍。作者得出结论：“目前尚不清楚可用营养物质支持的生物量的明显差异是否是由于浮游植物群落效率的差异，可能与铁的可用性或放牧压力有关。“他们建议，大陆架的宽度可被视为海底铁供应的替代指标。给定的常量营养素浓度的最低生物量是在秘鲁洪堡电流和北方加州地区的加州电流系统，这两个地区的低粉尘输入和相对狭窄的货架。在这个基于成就的更新项目中，加州大学圣克鲁斯分校的海洋微量金属地球化学家及其学生和同事将继续数十年的探索，以了解铁在中央加州洋流系统（cCCS）中的作用。 现场工作将结合联合收割机在地表沃茨和一系列垂直剖面中持续进行的铁和营养物数据。重点将包括cCCS内的三个区域：各种活跃的Fe-充满和Fe-耗尽的沿海上升流制度，涡流丰富的加州电流过渡区，是铁有限的，硝酸盐升高，但相对较低和均匀的叶绿素浓度，和离岸，寡营养加州电流。 他们将绘制铁和其他微量和常量营养素的表面和深度分布。 有四个具体的目标处理表征有机铁（III）结合的有机配体，确定铁（II）和铁（III）的浓度在缺氧沃茨的货架上，检查颗粒和溶解形式的铁之间的交换，并研究在涡流丰富的过渡沃茨的cCCS的涡流的作用。对科学的直接惠益：由于CCS在浮游植物生产力和支持更高营养水平方面的重要性，人们对CCS非常感兴趣。 到目前为止，CCS研究的重点一直是物理学和生物学之间的关系。这项研究将把微量营养素化学的重要作用插入到图片中。 它还将在提前确保船舶时间和为其他合作研究提供后勤支持方面发挥重要作用。 这对合作的科学家来说极具价值和成本效益，因为有了所提供的水文地理、营养和微量金属数据，他们可以专注于他们的免费研究工作。该项目将为UCSC的两名研究生提供资金，他们还将接受课程培训，包括i）科学交流，ii）海洋科学职业，（三）书面授权。该项目的一个更广泛的影响目标是，通过将研究目标转化为广泛分发的教学材料供课堂使用，促进海洋科学相关专题的教学。为了实现这一目标，该团队将与UCSC Long Marine Lab的Seymour Discovery Center合作。探索中心每年接待14，000名游客，该项目将提供资金，以开发一个关于限制CCS中营养物质和浮游植物水华发展的互动展示。