期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 108, 期 3, 页码 1076-1081出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1010963108
关键词
trace metals; carbohydrates; organic matter; exopolymeric substances; plankton
资金
- Australian Research Council [1092892]
- Australian Antarctic Division [2720]
- Antarctic Climate and Ecosystems Cooperative Research Center
- Commonwealth Scientific and Industrial Research Organization (CSIRO) Office of the Chief Executive
- University of Technology Sydney
- Belgian Federal Science Policy Office [SD/CA/03A]
- Belgian French Community (Actions de Recherche Concertee) [2/07-287]
- Netherlands Organisation for Scientific Research [851.20.046]
- New Zealand Foundation for Research Science and Technology Coasts and Oceans Outcome Based Investment
- European Network of Excellence EUR-OCEANS [511106-2]
Iron limits primary productivity in vast regions of the ocean. Given that marine phytoplankton contribute up to 40% of global biological carbon fixation, it is important to understand what parameters control the availability of iron (iron bioavailability) to these organisms. Most studies on iron bioavailability have focused on the role of siderophores; however, eukaryotic phytoplankton do not produce or release siderophores. Here, we report on the pivotal role of saccharides-which may act like an organic ligand-in enhancing iron bioavailability to a Southern Ocean cultured diatom, a prymnesiophyte, as well as to natural populations of eukaryotic phytoplankton. Addition of a monosaccharide (>2 nM of glucuronic acid, GLU) to natural planktonic assemblages from both the polar front and subantarctic zones resulted in an increase in iron bioavailability for eukaryotic phytoplankton, relative to bacterioplankton. The enhanced iron bioavailability observed for several groups of eukaryotic phytoplankton (i.e., cultured and natural populations) using three saccharides, suggests it is a common phenomenon. Increased iron bioavailability resulted from the combination of saccharides forming highly bioavailable organic associations with iron and increasing iron solubility, mainly as colloidal iron. As saccharides are ubiquitous, present at nanomolar to micromolar concentrations, and produced by biota in surface waters, they also satisfy the prerequisites to be important constituents of the poorly defined ligand soup, known to weakly bind iron. Our findings point to an additional type of organic ligand, controlling iron bioavailability to eukaryotic phytoplankton-a key unknown in iron biogeochemistry.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据