The Biogeochemistry of Dissolved Iron-ligands in Marine Cyanobacteria and Seawater

微量营养素金属，如铁和钴，对地球上的所有生命都至关重要，它们在环境中的有效性可以调节一个区域的初级生产力。在海洋中，高达99.9%的溶解铁，以及程度较小的钴，都被强大的有机结合分子结合，这些分子被称为配体，控制着这些金属中的哪些部分可供生物利用。要了解海洋中许多痕量金属限制初级生产的偏远地区的碳和营养循环，重要的是了解配体的分布和循环。在这项研究中，伍兹霍尔海洋研究所的一名研究人员将使用新技术来评估全球丰富的海洋蓝藻原氯球藻实验室培养物和南太平洋亚热带环流海水样本中天然铁和钴结合配体的多样性和组成。这项研究将大大增加对铁和钴有效性的解释，并有助于将元素金属分布、配体浓度和结合强度的测量与微生物群落的评估联系起来。更广泛的影响：该项目的成果将被纳入提倡者教授的研究生级别的有机地球化学课，并通过麻省理工学院和伍兹霍尔海洋研究所的网站公开提供。作为该项目的一部分，一名研究生将得到支持和培训。预计本科生还将有机会在暑期参与这项研究，并学习有机地球化学、微生物生物地球化学和建模。

Micronutrient trace metals, such as iron and cobalt, are critical to all life on earth, and their availability in the environment can regulate the primary productivity in a region. In the ocean, up to 99.9% of dissolved iron, and to a lesser extent cobalt, are bound by strong organic binding molecules, known as ligands which control what fraction of these metals is available to organisms. To understand carbon and nutrient cycling in many remote areas of the ocean where trace metals limit primary production, it is important to understand the distribution and cycling of ligands. In this study, a researcher at the Woods Hole Oceanographic Institute will use novel techniques to assess the diversity and composition of natural iron and cobalt binding ligands in laboratory cultures of the globally abundant marine cyanobacteria Prochlorococcus and in seawater samples from the South Pacific Subtropical Gyre. This study will add significantly to the interpretation of iron and cobalt availability, and help to link measurements of elemental metal distributions, ligand concentrations and binding strengths, and assessments of the microbial community. Broader Impacts: Results from the project would be incorporated into graduate level organic geochemistry classes taught by the proponent and be made publically available through the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution websites. One graduate student would be supported and trained as part of this project. It is anticipated that undergraduate students would also have the opportunity to participate in the study during the summer months and learn about organic geochemistry, microbial biogeochemistry, and modeling.