Supply and removal of trace elements in the subtropical South Pacific

在该RAPID奖的资助下，哥伦比亚大学拉蒙特-多尔蒂地球观测站的一个美国研究小组将研究南太平洋副热带环流中微量元素的供应和移除。 这将在德国布莱曼马克斯普朗克研究所的Tim Ferdelman博士的指导下在一个国际项目（UltraPac）的背景下完成，他邀请Lamont-Doherty团队加入德国科学家在智利安托法加斯塔和新西兰惠灵顿之间的研究船索内（2015年12月至2016年1月）上的考察。UltraPac是SPSG的协调跨学科研究，包括微生物学，分子生物学，浮游动物，气溶胶，痕量金属，固氮，碳和营养物地球化学等主题的研究。美国研究小组将测量铀和钍衰变系列中长寿命、天然存在的放射性同位素的溶解和微粒浓度，这些浓度可用于限制该制度内微量元素的供应和去除率。该项目还将为两名博士生提供教育，培训和专业发展，否则将无法通过他们的博士研究的其他方面。它还将为学生提供与外国合作者建立联系的机会，这将对他们的长期职业发展非常有益。该项目将使Lamont-Doherty科学家能够量化严重采样不足的SPSG中微量元素的供应和去除率，SPSG是海洋中最大的海洋地理省，其特点是超贫营养（低生物生产力）生态系统和超低粉尘通量。评价粉尘中微量元素的供应提供了关于影响SPSG生态和地球化学的必需微量营养素来源的关键信息。该奖项将涵盖两个人参加邮轮的旅费，往返邮轮的运费，以及分析邮轮上收集的样本的仪器费。 将SPSG的清除结果与最近对其他海洋地理学提供的研究结果进行比较，包括北太平洋副热带环流，亚北极北太平洋，北大西洋副热带环流和东热带南太平洋，将朝着该团队的长期目标发展，即从环境方面表征海洋微量元素去除的强度，海洋地理区的生态和地球化学特征。SPSG的深水柱受到东太平洋隆起产生的热液羽流的影响。将SPSG的结果与那些没有受到热液羽流重大影响的地区的结果进行比较，也将使他们能够限制这些羽流在确定深海微量元素全球分布方面的作用。这项工作应能提供没有计划由GEOTRACES海洋断面进行取样的端元海洋体系中生物必需微量营养素和其他微量元素的供应和清除率，从而填补GEOTRACES正在开发的全球微量元素和同位素数据库中的空白。将使用符合GEOTRACES的方法获得结果，并通过GEOTRACES数据库提供给其他领域的研究人员使用。

With funding from this RAPID award, an American research team at the Lamont-Doherty Earth Observatory of Columbia University will study the supply and removal of trace elements in the South Pacific Subtropical Gyre (SPSG). This will be done in the context of an international program (UltraPac) under the direction of Dr. Tim Ferdelman of the Max Planck Institute in Breman, Germany, who has invited the Lamont-Doherty team to join the German scientists aboard their expedition on the Research Vessel Sonne (December 2015 - January 2016) between Antofagasta, Chile and Wellington, New Zealand. UltraPac is a coordinated interdisciplinary study of the SPSG, including research on microbiology, molecular biology, zooplankton, aerosols, trace metals, nitrogen fixation, carbon and nutrient biogeochemistry, among other topics. The American team will measure dissolved and particulate concentrations of long-lived, naturally-occurring radioisotopes in the uranium and thorium decay series that can be used to provide constraints on the rates of supply and removal of trace elements within this regime. The project will also provide education, training and professional development for two PhD students that would otherwise be unavailable through other aspects of their PhD research. It will also provide an opportunity for the students to network with foreign collaborators, which will be very beneficial to their long-term career development. This project will enable the Lamont-Doherty scientists to quantify the rates of supply and removal of trace elements in the severely undersampled SPSG, the ocean's largest biogeographic province, characterized by a hyper-oligotrophic (low biological productivity) ecosystem and ultra-low dust fluxes. Evaluating the supply of trace elements from dust provides critical information about sources of essential micronutrients that influence the ecology and biogeochemistry of the SPSG. The award will cover the travel expenses for two people to participate in the cruise, shipping to and from the cruise, and instrument fees to analyze samples collected on the cruise. Comparing scavenging results from the SPSG with results from recent studies of other biogeographic providences, including the North Pacific Subtropical Gyre, the Subarctic North Pacific, the North Atlantic Subtropical Gyre and the Eastern Tropical South Pacific, will build toward the team's long-range goal of characterizing the intensity of trace element removal from the ocean in terms of environmental, ecological and biogeochemical characteristics of ocean biogeographic provinces. The deep water column of the SPSG is influenced by the hydrothermal plume emanating from the East Pacific Rise. Comparing SPSG results with those from regions lacking significant influence by hydrothermal plumes will also enable them to constrain the role of these plumes in defining the global distribution of trace elements in the deep ocean. This effort should provide rates of supply and removal of biologically essential micronutrients, and of other trace elements, in an end-member ocean regime that is not scheduled for sampling by a GEOTRACES ocean section, thus filling a gap in the global database for trace elements and isotopes under development by GEOTRACES. Results will be obtained using GEOTRACES-compliant methods, and made available through the GEOTRACES database for use by investigators in other fields.