Collaborative Research: Understanding the Massive Phytoplankton Blooms over the Australian-Antarctic Ridge

合作研究：了解澳大利亚-南极海脊上空大量浮游植物的繁殖

• 批准号: 2135184
• 负责人: Kevin Arrigo
• 金额: $ 127.53万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2135184&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; Massive; Phytoplankton

Phytoplankton blooms throughout the world’s oceans support critical marine ecosystems and help remove carbon dioxide (CO2) from the atmosphere. Traditionally, it has been assumed that phytoplankton blooms in the Southern Ocean are stimulated by iron from either nearby land or sea-ice. However, recent work demonstrates that hydrothermal vents may be an additional iron source for phytoplankton blooms. This enhancement of phytoplankton productivity by different iron sources supports rich marine ecosystems and leads to the sequestration of carbon in the deep ocean. Our proposed work will uncover the importance of hydrothermal activity in stimulating a large phytoplankton bloom along the southern boundary of the Antarctic Circumpolar Current just north of the Ross Sea. It will also lead towards a better understanding of the overall impact of hydrothermal activity on the carbon cycle in the Southern Ocean, which appears to trigger local hotspots of biological activity which are a potential sink for atmospheric CO2. This project will encourage the participation of underrepresented groups in ocean sciences, as well as providing educational opportunities for high school and undergraduate students, through three different programs. Stanford University’s Summer Undergraduate Research in Geoscience and Engineering (SURGE) program provides undergraduates from different US universities and diverse cultural backgrounds the opportunity to spend a summer doing a research project at Stanford. The Stanford Earth Summer Undergraduate Research Program (SESUR) is for Stanford undergraduates who want to learn more about environmental science by performing original research. Finally, Stanford’s School of Earth, Energy, and Environmental Sciences High School Internship Program enables young scientists to serve as mentors, prepares high school students for college, and serves to strengthen the partnership between Stanford and local schools. Students present their results at the Fall AGU meeting as part of the AGU Bright STaRS program. This project will form the basis of at least two PhD dissertations. The Stanford student will participate in Stanford’s Woods Institute Rising Environmental Leaders Program (RELP), a year-round program that helps graduate students hone their leadership and communication skills to maximize the impact of their research. The graduate student will also participate in Stanford’s Grant Writing Academy where they will receive training in developing and articulating research strategies to tackle important scientific questions. This interdisciplinary program combines satellite and ship-based measurements of a large poorly understood phytoplankton bloom (the AAR bloom) in the northwestern Ross Sea sector of the Southern Ocean with a detailed modeling study of the physical processes linking deep dissolved iron (DFe) reservoirs to the surface phytoplankton bloom. Prior to the cruise, we will implement a numerical model (CROCO) for our study region so that we can better understand the circulation, plumes, turbulence, fronts, and eddy field around the AAR bloom and how they transport and mix hydrothermally produced DFe vertically. Post cruise, observations of the vertical distribution of 3He (combined with DMn and DFe), will be used as initial conditions for a passive tracer in the model, and tracer dispersal will be assessed to better quantify the role of the various turbulent processes in upwelling DFe-rich waters to the upper ocean. The satellite-based component of the program will characterize the broader sampling region before, during, and after our cruise. During the cruise, our automated software system at Stanford University will download and process images of sea ice concentration, Chl-a concentration, sea surface temperature (SST), and sea surface height (SSH) and send them electronically to the ship. Operationally, our goal is to use all available satellite data and preliminary model results to target shipboard sampling both geographically and temporally to optimize sampling of the AAR bloom. We will use available BGC-Argo float data to help characterize the AAR bloom. In collaboration with SOCCOM, we will deploy additional BGC-Argo floats (if available) during our transit through the study area to allow us to better characterize the bloom. The centerpiece of our program will be a 40-day process study cruise in austral summer. The cruise will consist of an initial “radiator” pattern of hydrographic surveys/sections along the AAR followed by CTDs to selected submarine volcanoes. When/if eddies are identified, they will be sampled either during or after the initial surveys. The radiator pattern, or parts thereof, will be repeated 2-3 times. Hydrographic survey stations will include vertical profiles of temperature, salinity, oxygen, oxidation-reduction potential, light scatter, and PAR (400-700 nm). Samples will be collected for trace metals, ligands, 3He, and total suspended matter. Where intense hydrothermal activity is identified, samples for pH and total CO2 will also be collected to characterize the hydrothermal system. Water samples will be collected for characterization of macronutrients, and phytoplankton physiology, abundance, species composition, and size. During transits, we will continuously measure atmospheric conditions, current speed and direction, and surface SST, salinity, pCO2, and fluorescence from the ship’s systems to provide detailed maps of these parameters. The ship will be used as a platform for conducting phytoplankton DFe bioassay experiments at key stations throughout the study region both inside and outside the bloom. We will also perform detailed comparisons of algal taxonomic composition, physiology, and size structure inside and outside the bloom to determine the potential importance of each community on local biogeochemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

全球海洋中的浮游植物血液支持关键的海洋生态系统，并有助于从大气中清除二氧化碳（CO2）。传统上，人们认为，南大洋中的浮游植物血被靠近陆地或海冰的铁刺激。但是，最近的工作表明，水热通风孔可能是浮游植物血液的附加铁源。通过不同铁源来增强浮游植物生产力的增强，支持丰富的海洋生态系统，并导致深海中碳的隔离。我们提出的工作将揭示水热活动在刺激沿南极循环电流的南部边界的大型浮游植物盛开中的重要性。这也将使人们更好地理解水热活动对南大洋碳循环的总体影响，这似乎触发了生物学活动的局部热点，这是大气中二氧化碳的潜在水槽。该项目将鼓励代表性不足的团体参与海洋科学，并通过三种不同的计划为高中和本科生提供教育机会。斯坦福大学的地球科学和工程学夏季本科研究（Surge）计划为来自美国不同大学和多元化文化背景的本科生提供了在斯坦福大学度过一个研究项目的机会。斯坦福大学夏季本科研究计划（SESUR）是针对斯坦福大学的本科生，他们希望通过进行原始研究来了解有关环境科学的更多信息。最后，斯坦福大学的地球，能源和环境科学学院高中实习计划使年轻科学家能够担任导师，为高中学生做好准备，并为加强斯坦福大学与当地学校之间的伙伴关系。作为AGU Bright Stars计划的一部分，学生在秋季AGU会议上展示了他们的结果。该项目将构成至少两次博士学位论文的基础。这位斯坦福大学的学生将参加斯坦福大学伍兹研究所（Stanford）的崛起环境领导者计划（RELP），这是一项全年计划，可帮助研究生磨练他们的领导力和沟通技巧，以最大程度地提高他们的研究影响。研究生还将参加斯坦福大学的赠款写作学院，在那里他们将接受制定和表达研究策略的培训，以解决重要的科学问题。该跨学科计划结合了卫星和基于船舶的测量值，该计划对南部海洋西北部罗斯海洋部门的大型植物浮游生物（AAR Bloom）以及将深层溶解的铁（DFE）储存到表面植物植物植物植物的物理过程进行了详细的建模研究。在巡航之前，我们将为我们的研究区域实施数值模型（Croco），以便我们可以更好地了解AAR Bloom周围周围的循环，羽，湍流，前部和涡流，以及它们如何垂直运输和混合氢化体生产的DFE。巡航后，对3HE的垂直分布的观察（与DMN和DFE结合）将用作模型中被动示踪剂的初始条件，并且将评估示踪剂分散体，以更好地量化各种湍流过程在上升富含DFE的DFE DFE富裕水域中的作用。该程序的基于卫星的组件将在我们的巡航之前，之中和之后表征更广泛的采样区域。在巡航期间，我们在斯坦福大学的自动化软件系统将下载并处理海冰浓度，CHL-A浓度，海面温度（SST）和海面高度（SSH）的图像，并将其电子方式发送到船上。在操作上，我们的目标是使用所有可用的卫星数据和初步模型结果来针对地理位置和临时进行船上采样，以优化AAR Bloom的采样。我们将使用可用的BGC-ARGO浮点数据来帮助表征AAR Bloom。通过与SOCCOM合作，我们将在通过研究区域的过境期间部署其他BGC-Argo浮子（如果有），以使我们能够更好地描述Bloom。我们计划的核心将是在澳大利亚夏季进行的40天工艺研究巡游。该巡航将包括沿AAR的水文调查/部分的初始“散热器”模式，然后是CTD到选定的海底火山。当/如果确定涡流时，将在初始调查期间或之后对它们进行采样。散热器图案或其部分将重复2-3次。水文调查站将包括温度，盐度，氧气，氧化还原电位，光散射和PAR（400-700 nm）的垂直轮廓。将收集用于微量金属，配体，3HE和总悬浮物的样品。在确定强烈的热液活性的地方，还将收集pH和总二氧化碳的样品以表征热液系统。水样将收集以表征大量营养素，以及浮游植物生理学，抽象，物种组成和大小。在过渡期间，我们将继续测量大气条件，当前速度和方向以及船体系统中的表面SST，盐度，PCO2和荧光，以提供这些参数的详细地图。该船将用作在整个研究区域内部和盛开室内的关键站点进行浮游植物DFE生物测定实验的平台。我们还将对Bloom内部和外部的藻类分类学组成，生理学和大小结构进行详细比较，以确定每个社区对本地生物地球化学的潜在重要性。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛的影响审查的审查标准来通过评估来获得的支持。