Collaborative Research: Free-drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean

在过去的十年里，气候变暖与冰川消退、冰架解体以及南大洋冰山日益增多有关。我们对西北韦德尔海的两座冰山的初步研究表明，陆地物质的大量输送伴随着浮游植物和浮游动物/微型生物丰度的显著增加，以及冰山周围的初级生产。我们假设，自由漂移的冰山的营养丰富将增加有机碳的初级生产和沉积，从而增加南大洋二氧化碳的吸收和封存，并影响全球碳循环。1)自由漂流冰山的物理动力学与Fe和周围水柱的营养盐分布有什么关系？2)Fe与自由漂流冰山的营养盐分布以及冰附和周围浮游动物群落(微生物、浮游动物、微型生物)的有机碳动态有什么关系？3)混合层对颗粒有机碳的输出通量有什么影响？提出了一种跨学科的方法来研究冰山的结构和动力学、生物地球化学过程和碳循环，其中包括测量微量元素、营养物质和放射性核素的分布；微生物、附着在冰上的和浮游动物群落介导的有机碳动力学；以及颗粒有机碳输出通量。该项目的成果将进一步加深我们对气候变化与南大洋碳封存之间关系的理解。我们的发现将被纳入海洋探索中心(OEC)南极研究部，作为SIOExplorer：数字图书馆项目的一部分。OEC允许用户访问内容，这些内容分为四个级别之一：入门(K-6年级)、学生(6-12年级)、学院和研究。研究生、本科生、教师和志愿者是拟议的现场和实验室工作的重要参与者。对于K-12级别，一名专业的儿童书籍作家将参加巡游，以制作关于探险的报道和一个日常互动网站。

Atmospheric warming has been associated with retreating glaciers, disintegrating ice shelves, and the increasing prevalence of icebergs in the Southern Ocean over the last decade. Our preliminary study of two icebergs in the NW Weddell Sea, an area of high iceberg concentration, showed significant delivery of terrestrial material accompanied by significant enhancement of phytoplankton and zooplankton/micronekton abundance, and primary production surrounding the icebergs. We hypothesize that nutrient enrichment by free-drifting icebergs will increase primary production and sedimentation of organic carbon, thus increasing the draw-down and sequestration of CO2 in the Southern Ocean and impacting the global carbon cycle. Our research addresses the following questions:1) What is the relationship between the physical dynamics of free-drifting icebergs and the Fe and nutrient distributions of the surrounding water column? 2) What is the relationship between Fe and nutrient distributions associated with free-drifting icebergs and the organic carbon dynamics of the ice-attached and surrounding pelagic communities (microbes, zooplankton, micronekton)? 3) What is impact on the export flux of particulate organic carbon from the mixed layer? An interdisciplinary approach is proposed to examine iceberg structure and dynamics, biogeochemical processes, and carbon cycling that includes measurement of trace element, nutrient and radionuclide distributions; organic carbon dynamics mediated by microbial, ice-attached and zooplankton communities; and particulate organic carbon export fluxes. Results from this project will further our understanding of the relationship between climate change and carbon sequestration in the Southern Ocean. Our findings will be incorporated into the Antarctic Research division of the Ocean Exploration Center (OEC) as part of the SIOExplorer: Digital Library Project. The OEC allows users to access content, which is classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. Graduate students, undergraduates, teachers, and volunteers are important participants in the proposed field and laboratory work. For the K-12 level, a professional writer of children's books will participate in cruises to produce an account of the expedition and a daily interactive website.