US GEOTRACES North Atlantic Section: Sample collection for iron stable isotopes

GEOTRACES是一个新发起的国际海洋学计划，旨在确定控制海洋中关键微量元素和同位素分布的过程和量化通量，并了解这些分布对不断变化的环境条件的敏感性。 溶解铁（Fe）是一种对海洋浮游植物生长、生态系统生产力和碳固存具有深远影响的元素。 大气粉尘沉降、大陆边缘沉积物溶解铁通量和富铁流体的热液喷发都被认为是生物利用铁向海洋的重要来源。 然而，这些来源在向溶解相提供Fe方面的相对重要性还没有得到很好的理解。 为了解决这一问题，加州理工学院的一名科学家将与LEGOS（法国）的研究人员合作，对2010年GEOTRACES巡航沿着北大西洋海盆收集的样本进行铁稳定同位素测量。 将从影响痕量金属及其同位素的所有物理和地球化学过程中取样，即强对流平流、海洋边缘交换、大气输入和热液源和热液汇。 由此产生的数据集应有助于限制全球铁通量的海洋。 至于更广泛的影响，该研究将对铁的地球化学循环产生新的见解，铁是解决碳循环所需的重要组成部分。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).GEOTRACES is a newly initiated international oceanographic program to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the oceans and to establish an understanding of the sensitivity of these distributions to changing environmental conditions. Dissolved iron (Fe) is an element that has a profound impact on phytoplankton growth, ecosystem productivity, and carbon sequestration in the ocean. Atmospheric dust deposition, dissolved Fe flux from continental margin sediments, and hydrothermal venting of Fe-rich fluids have all been identified as important sources of biologically utilized Fe to the oceans. However, the relative importance of these sources in supplying Fe to the dissolved phase is not well understood. To address this issue, a scientist from the California Institute of Technology in collaboration with researchers at LEGOS (France) will make Fe stable isotopic measurement on samples collected during the 2010 GEOTRACES cruise along the North Atlantic Ocean basin. Samples will be taken from all physical and biogeochemical processes that influence trace metals and their isotopes, namely strong meridional advection, ocean margin exchange, atmospheric inputs, and hydrothermal sources and sinks. The resultant dataset should help constrain global Fe fluxes to the ocean. As regards broader impacts, the study will yield new insights into the biogeochemical cycle of Fe, an important component needed to resolve the carbon cycle.