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

在过去十年中，大气变暖与冰川退缩、冰架解体以及南大洋冰山的增加有关。我们对西北威德尔海（NW Weddell Sea）两座冰山的初步研究表明，随着浮游植物和浮游动物/微浮游生物丰度的显著增强，陆生物质的大量输送以及冰山周围的初级生产。我们假设，自由漂流冰山的营养富集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。我们的研究解决了以下问题：1)自由漂流冰山的物理动力学与周围水柱的铁和养分分布之间的关系是什么？2)与自由漂流冰山相关的铁与营养物分布以及附冰和周围浮游生物群落（微生物、浮游动物、微浮游生物）有机碳动态之间的关系是什么？3)对混合层颗粒有机碳出口通量有何影响？提出了一种跨学科的方法来研究冰山结构和动力学、生物地球化学过程和碳循环，包括微量元素、营养物质和放射性核素分布的测量；微生物、冰附体和浮游动物群落介导的有机碳动态微粒有机碳输出通量。该项目的结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）的南极研究部门，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：入门级（K-6年级）、学生级（6-12年级）、大学级和研究级。研究生、本科生、教师和志愿者是拟议的实地和实验室工作的重要参与者。对于K-12年级的学生，将有一名专业的儿童书籍作家参与游船活动，制作一份探险记录和一个每日互动网站。

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.