Collaborative Research: Plankton Community Structure and Iron Distribution in the Southern Drake Passage and Scotia Sea

南大洋德雷克海峡的沙克尔顿断裂带（SFZ）定义了浮游植物沃茨的低层和高层之间的边界。低叶绿素水流经德雷克海峡南部出现高叶绿素水的东部，最近的证据表明，南南极绕极流锋（SACF）转向南方的SFZ到南极半岛大陆架的水类型之间的混合发生。混合水，然后平流小康架与升高的铁和浮游植物生物量。因此，SFZ是一个理想的天然实验室，以提高浮游生物群落对天然铁施肥的反应，以及这些过程如何影响有机碳出口到海洋内部的理解。假设该地区的水深会影响中尺度环流和铁的输送，从而导致观察到的浮游植物生物量模式。进一步假设南极绕极流（ACC）的位置影响ACC水流入半岛大陆架的幅度，介导铁运输到斯科舍海的量。为了解决这些假设，将在SFZ附近和南部斯科舍海以东进行一次研究巡航。一个中尺度站网格的垂直剖面，水取样，瓶孵化富集实验将补充快速表面调查的化学，浮游生物和水文特性。将确定锰、铝和镭同位素的分布，以追踪铁源并估计混合率。将研究浮游植物和细菌的生理状态（包括对铁富集的反应）以及浮游生物群落的结构。主要目标是更好地了解南大洋的浮游生物生产力、群落结构和出口生产如何受到水深测量、中尺度环流和限制性营养物分布之间的耦合的影响。拟议的工作代表了一个跨学科的方法来解决的基本物理，化学和生物过程，有助于在叶绿素a发生的SFZ附近的突然转变。鉴于最近有迹象表明南大洋正在变暖，必须进一步了解调节目前生态系统结构的条件，以便预测气候变化的影响。该项目将促进广泛群体的培训和学习。基金包括支持博士后，研究生和本科生。此外，该项目还将为极地科学站网站的内容开发做出贡献，自2001年以来，该网站一直是成人教育、家庭教育、部落学校、教养教育、家庭扫盲方案和一般公众的教师和学生的资源。

The Shackleton Fracture Zone (SFZ) in Drake Passage of the Southern Ocean defines a boundary between low and high phytoplankton waters. Low chlorophyll water flowing through the southern Drake Passage emerges as high chlorophyll water to the east, and recent evidence indicates that the Southern Antarctic Circumpolar Current Front (SACCF) is steered south of the SFZ onto the Antarctic Peninsula shelf where mixing between the water types occurs. The mixed water is then advected off-shelf with elevated iron and phytoplankton biomass. The SFZ is therefore an ideal natural laboratory to improve the understanding of plankton community responses to natural iron fertilization, and how these processes influence export of organic carbon to the ocean interior. The bathymetry of the region is hypothesized to influence mesoscale circulation and transport of iron, leading to the observed patterns in phytoplankton biomass. The position of the Antarctic Circumpolar Current (ACC) is further hypothesized to influence the magnitude of the flow of ACC water onto the peninsula shelf, mediating the amount of iron transported into the Scotia Sea. To address these hypotheses, a research cruise will be conducted near the SFZ and to the east in the southern Scotia Sea. A mesoscale station grid for vertical profiles, water sampling, and bottle incubation enrichment experiments will complement rapid surface surveys of chemical, plankton, and hydrographic properties. Distributions of manganese, aluminum and radium isotopes will be determined to trace iron sources and estimate mixing rates. Phytoplankton and bacterial physiological states (including responses to iron enrichment) and the structure of the plankton communities will be studied. The primary goal is to better understand how plankton productivity, community structure and export production in the Southern Ocean are affected by the coupling between bathymetry, mesoscale circulation, and distributions of limiting nutrients. The proposed work represents an interdisciplinary approach to address the fundamental physical, chemical and biological processes that contribute to the abrupt transition in chl-a which occurs near the SFZ. Given recent indications that the Southern Ocean is warming, it is important to advance the understanding of conditions that regulate the present ecosystem structure in order to predict the effects of climate variability. This project will promote training and learning across a broad spectrum of groups. Funds are included to support postdocs, graduate students, and undergraduates. In addition, this project will contribute to the development of content for the Polar Science Station website, which has been a resource since 2001 for instructors and students in adult education, home schooling, tribal schools, corrections education, family literacy programs, and the general public.