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

南极洲周围的沿海沃茨是地球上生物最丰富、最未受破坏的生态系统之一。在很大程度上，这种生物丰富性集中在南极大陆附近广阔的海冰上的众多开口（这些开口被称为冰穴）。这些冰穴代表了被称为热点的产量增加的区域，并支持南大洋最高的动物密度。它们中的许多还位于巨大的南极冰盖的漂浮延伸附近，每年夏天都会接收大量的融水径流。然而，人们对使这些生态系统如此具有生物生产力的具体过程知之甚少。在目前已知的46个南极沿海冰穴中，只有少数得到了详细的调查。该项目将为罗斯海冰穴、阿蒙森冰穴和松岛冰穴开发生态系统模型;这三个冰穴是南极最具生产力的沿海冰穴。主要目标是使用这些模型来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中具有生物生产力，但在某些方面（例如大小和生产力）不同。还将扩大建模工作，以潜在地评估这些生态系统过去可能如何运作，以及它们在不同的物理、化学和气候背景下未来可能如何变化。该项目将通过斯坦福大学推进代表性不足的少数民族的教育？在地球科学与工程（浪涌）计划的夏季本科生研究。SURGE将为本科生提供在斯坦福大学获得工程和地球科学指导研究经验的机会。老自治领大学还将利用当地公立和私立学校的推广计划，以及一个正在进行的支持童子军海洋学奖章计划的计划，以创造推广和教育的影响。Polynyas（被海冰包围的开放水域）是极地生态系统中不成比例的生产区域，但对其高生产率的控制尚不清楚。该项目将提供控制浮游植物丰度和生产力的物理和化学过程的定量评估，这些过程在不同的海穴中有何不同，以及海穴在未来可能如何变化。特别令人感兴趣的是冰穴内过程之间的相互作用以及附近冰盖（包括思韦茨冰川和松岛冰川）夏季融化的情况。在这项拟议的研究中，我们将开发一套全面的，高分辨率的耦合物理生物模型，并实施这些三个主要的，但不同的，南极冰穴。这些冰穴，罗斯海冰穴，阿蒙森冰穴和松岛冰穴，占南极冰穴总产量的50%。要解决的研究问题是：1）什么样的环境因素发挥最大的控制初级生产在南极洲周围的冰穴？2)什么是控制物理，导致溶解铁（dFe）供应的不均匀性，以真光层在冰槽南极大陆架周围？这对当地的初级生产率有什么影响？3)在未来几十年中，由于气候引起的物理变化（风、海冰、冰架基底融化、跨冰架交换、分层和垂直混合），真光层的dFe供应可能发生什么变化，这将如何影响整个大陆的初级生产力？罗斯海、阿蒙森和松岛是南极洲取样最好的几个冰穴，有助于模型参数化和验证。此外，这些冰穴在大小、位置、海冰动态、与融化的冰架的关系以及与大陆架断裂的距离方面差异很大，使它们成为理想的案例研究。作为比较，还将模拟南极西部半岛（wAP），这是一个多产大陆架，其中冰穴对生物产量的贡献相对较小。调查不同类型的南极沿海沃茨内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。

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.