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Collaborative Research: Elucidating Environmental Controls of Productivity in Polynas and the Western Antarctic Peninsula

合作研究：阐明波里纳斯和南极西部半岛生产力的环境控制

基本信息

批准号：
1643652
负责人：
Eileen Hofmann
金额：
$ 25.2万
依托单位：
Old Dominion University Research Foundation
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-15 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643652&HistoricalAwards=false
关键词：
Collaborative Research Elucidating Environmental Controls

项目摘要

Coastal waters surrounding Antarctica represent some of the most biologically rich and most untouched ecosystems on Earth. In large part, this biological richness is concentrated within the numerous openings that riddle the expansive sea ice (these openings are known as polynyas) near the Antarctic continent. These polynyas represent regions of enhanced production known as hot-spots and support the highest animal densities in the Southern Ocean. Many of them are also located adjacent to floating extensions of the vast Antarctic Ice Sheet and receive a substantial amount of meltwater runoff each year during the summer. However, little is known about the specific processes that make these ecosystems so biologically productive. Of the 46 Antarctic coastal polynyas that are presently known, only a handful have been investigated in detail. This project will develop ecosystem models for the Ross Sea polynya, Amundsen polynya, and Pine Island polynya; three of the most productive Antarctic coastal polynyas. The primary goal is to use these models to better understand the fundamental physical, chemical, and biological interacting processes and differences in these processes that make these systems so biologically productive yet different in some respects (e.g. size and productivity) during the present day settings. Modeling efforts will also be extended to potentially assess how these ecosystems may have functioned in the past and how they might change in the future under different physical and chemical and climatic settings. The project will advance the education of underrepresented minorities through Stanford?s Summer Undergraduate Research in Geoscience and Engineering (SURGE) Program. SURGE will provide undergraduates the opportunity to gain mentored research experiences at Stanford University in engineering and the geosciences. Old Dominion University also will utilize an outreach programs for local public and private schools as well as an ongoing program supporting the Boy Scout Oceanography merit badge program to create outreach and education impacts. Polynyas (areas of open water surrounded by sea ice) are disproportionately productive regions of polar ecosystems, yet controls on their high rates of production are not well understood. This project will provide quantitative assessments of the physical and chemical processes that control phytoplankton abundance and productivity within polynyas, how these differ for different polynyas, and how polynyas may change in the future. Of particular interest are the interactions among processes within the polynyas and the summertime melting of nearby ice sheets, including the Thwaites and Pine Island glaciers. In this proposed study, we will develop a set of comprehensive, high resolution coupled physical-biological models and implement these for three major, but diverse, Antarctic polynyas. These polynyas, the Ross Sea polynya, the Amundsen polynya, and Pine Island polynya, account for 50% of the total Antarctic polynya production. The research questions to be addressed are: 1) What environmental factors exert the greatest control of primary production in polynyas around Antarctica? 2) What are the controlling physics that leads to the heterogeneity of dissolved iron (dFe) supply to the euphotic zone in polynyas around the Antarctic continental shelf? What effect does this have on local rates of primary production? 3) What are the likely changes in the supply of dFe to the euphotic zone in the next several decades due to climate-induced changes in the physics (winds, sea-ice, ice shelf basal melt, cross-shelf exchange, stratification and vertical mixing) and how will this affect primary productivity around the continent? The Ross Sea, Amundsen, and Pine Island polynyas are some of the best-sampled polynyas in Antarctica, facilitating model parameterization and validation. Furthermore, these polynyas differ widely in their size, location, sea ice dynamics, relationship to melting ice shelves, and distance from the continental shelf break, making them ideal case studies. For comparison, the western Antarctic Peninsula (wAP), a productive continental shelf where polynyas are a relatively minor contributor to biological production, will also be modeled. Investigating specific processes within different types Antarctic coastal waters will provide a better understand of how these important biological oases function and how they might change under different environmental conditions.

南极洲周围的沿海水域代表了地球上生物最丰富、最原始的生态系统。在很大程度上，这种生物丰富度集中在南极大陆附近广阔海冰上的众多开口（这些开口被称为冰间湖）。这些冰间湖代表了被称为热点的生产增强区域，并支持南大洋最高的动物密度。其中许多还毗邻巨大的南极冰盖的浮动延伸部分，每年夏季都会接收大量的融水径流。然而，人们对这些生态系统具有如此高生物生产力的具体过程知之甚少。目前已知的 46 个南极沿海冰间湖中，只有少数得到了详细调查。该项目将为罗斯海冰间湖、阿蒙森冰间湖和松岛冰间湖开发生态系统模型；三个生产力最高的南极沿海冰间湖。主要目标是使用这些模型更好地理解基本的物理、化学和生物相互作用过程以及这些过程中的差异，这些过程使这些系统在当今环境下具有如此高的生物生产力，但在某些方面（例如大小和生产力）有所不同。建模工作还将扩展到潜在地评估这些生态系统在过去如何运作以及它们在未来在不同的物理、化学和气候环境下可能如何变化。该项目将通过斯坦福大学地球科学与工程暑期本科生研究 (SURGE) 计划推进代表性不足的少数族裔的教育。 SURGE 将为本科生提供在斯坦福大学获得工程和地球科学领域指导研究经验的机会。奥道明大学还将利用当地公立和私立学校的外展计划以及支持童子军海洋学优异徽章计划的持续计划来创造外展和教育影响。冰间湖（被海冰包围的开放水域）是极地生态系统中生产力极高的区域，但对其高生产力的控制尚不清楚。该项目将对控制冰间湖内浮游植物丰度和生产力的物理和化学过程进行定量评估，不同冰间湖的这些过程有何不同，以及冰间湖未来可能如何变化。特别令人感兴趣的是冰间湖内部过程与附近冰盖（包括思韦茨冰川和松岛冰川）夏季融化之间的相互作用。在这项拟议的研究中，我们将开发一套全面的、高分辨率耦合的物理生物模型，并将这些模型应用于三个主要但多样化的南极冰间湖。这些冰间湖，即罗斯海冰间湖、阿蒙森冰间湖和松岛冰间湖，占南极冰间湖总产量的50%。要解决的研究问题是：1）哪些环境因素对南极洲周围冰间湖的初级生产发挥最大的控制作用？ 2) 导致南极大陆架周围冰间湖富光带溶解铁（dFe）供应不均匀的物理控制因素是什么？这对当地初级生产力有何影响？ 3）由于气候引起的物理变化（风、海冰、冰架基底融化、跨陆架交换、分层和垂直混合），未来几十年内富光带的 dFe 供应可能会发生哪些变化？这将如何影响大陆周围的初级生产力？罗斯海、阿蒙森和松岛冰间湖是南极洲采样最好的冰间湖，有利于模型参数化和验证。此外，这些冰间湖在大小、位置、海冰动态、与冰架融化的关系以及距大陆架断裂的距离方面差异很大，使它们成为理想的研究案例。为了进行比较，还将对南极半岛西部（wAP）进行建模，这是一个富有成效的大陆架，其中冰间湖对生物生产的贡献相对较小。研究不同类型的南极沿海水域的具体过程将有助于更好地了解这些重要的生物绿洲如何发挥作用以及它们在不同环境条件下可能如何变化。