Collaborative Research: Iron and phosphorus balanced limitation of nitrogen fixation in the oligotrophic ocean

合作研究：贫营养海洋固氮的铁磷平衡限制

基本信息

批准号：
1657766
负责人：
Mak Saito
金额：
$ 48.8万
依托单位：
Woods Hole Oceanographic Institution
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-03-01 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1657766&HistoricalAwards=false
关键词：
Collaborative Research Iron phosphorus balanced

项目摘要

Marine cyanobacteria are able to use or "fix" atmospheric nitrogen gas, and so supply much of the essential nutrient nitrogen that supports open ocean food chains. Oceanographers have usually thought that the growth of these nitrogen-fixing cyanobacteria is limited at any particular time and place by the supply of either iron, or of phosphorus. Preliminary experiments have shown, though, that these nitrogen fixers instead grow best when both iron and phosphorus are scarce at the same time. In this project, the researchers will use cellular indicators that are specific for iron and phosphorus limitation to determine how important this type of "balanced limitation" of nitrogen-fixing cyanobacteria is in controlling the productivity of ocean food chains in the tropical Atlantic Ocean. Two graduate students will be trained at the University of Southern California (USC) and Woods Hole Oceanographic Institution, as well as a postdoctoral researcher at USC. Educational outreach efforts will take place at a Los Angeles inner city high school with a student body that is over 98% Hispanic and African-American, and with underrepresented undergraduates in the USC Global Environmental Microbiology course. In addition, two Research Experiences for Undergraduates students will be supervised for summer research projects to help them learn about science career options. The researchers will investigate the biological and biogeochemical consequences of this unique balanced iron/phosphorus-limited phenotype, using both laboratory and fieldwork approaches. During the first year of this project, the nitrogen-fixing cyanobacteria will be cultured under iron and/or phosphorus limitation, followed by application of proteomics and transcriptomics to identify genes that are potential diagnostic biomarkers for iron/phosphorus balanced limitation. Preliminary work has already identified one promising candidate biomarker in one cyanobacterium, an EzrA protein domain that appears to be associated with the cell size decreases seen specifically under balanced limitation, and the researchers have identified numerous other potential candidates for similar biomarkers. During the second year, these new co-limitation biomarkers and others previously validated for iron limitation (IsiB) and phosphorus limitation (SphX) will be used to investigate balanced limitation during a research cruise transecting from relatively high-iron, low-phosphorus North Atlantic waters, to the relatively high-phosphorus, low-iron South Atlantic. This fieldwork component will survey nitrogen fixing cyanobacteria populations across this natural iron/phosphorus gradient for genetic, proteomic, and physiological indicators of balanced limitation, as well as testing their responses to iron and phosphorus manipulations in shipboard incubation experiments. The third year will be devoted to sample analysis, and publications exploring the responses of oceanic nitrogen fixers to simultaneous limitation by both iron and phosphorus.

海洋蓝藻能够利用或“固定”大气中的氮气，因此提供了支持开放海洋食物链的大量必需营养氮。海洋学家通常认为，这些固氮蓝藻的生长在任何特定时间和地点都受到铁或磷供应的限制。不过，初步实验表明，当铁和磷同时稀缺时，这些固氮剂反而生长得最好。在这个项目中，研究人员将使用特定于铁和磷限制的细胞指标来确定固氮蓝藻的这种“平衡限制”在控制热带大西洋海洋食物链的生产力方面有多重要。两名研究生将在南加州大学（USC）和伍兹霍尔海洋研究所接受培训，一名博士后研究员将在南加州大学接受培训。教育推广工作将在洛杉矶市中心的一所高中进行，该高中的学生人数超过 98% 是西班牙裔和非裔美国人，南加州大学全球环境微生物学课程的本科生人数不足。此外，还将对本科生的两名研究经历进行夏季研究项目的监督，以帮助他们了解科学职业选择。研究人员将利用实验室和现场工作方法研究这种独特的平衡铁/磷限制表型的生物学和生物地球化学后果。在该项目的第一年，固氮蓝藻将在铁和/或磷限制下培养，然后应用蛋白质组学和转录组学来鉴定作为铁/磷平衡限制的潜在诊断生物标志物的基因。初步工作已经在一种蓝藻中发现了一种有希望的候选生物标志物，这是一种 EzrA 蛋白结构域，它似乎与平衡限制下特别观察到的细胞大小减小有关，并且研究人员还发现了许多其他类似生物标志物的潜在候选物。在第二年，这些新的共同限制生物标志物和其他先前针对铁限制 (IsiB) 和磷限制 (SphX) 进行验证的生物标志物将用于研究从相对高铁、低磷的北大西洋横断的研究巡航期间的平衡限制水域，到相对高磷、低铁的南大西洋。该实地工作部分将调查天然铁/磷梯度上的固氮蓝藻种群，以了解平衡限制的遗传、蛋白质组和生理指标，并测试它们对船上孵化实验中铁和磷操作的反应。第三年将致力于样本分析和出版物，探索海洋固氮剂对铁和磷同时限制的反应。

项目成果

期刊论文数量（14）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Copper stress in Staphylococcus aureus leads to adaptive changes in central carbon metabolism

DOI：
10.1039/c8mt00239h
发表时间：
2019-01-01
期刊：
METALLOMICS
影响因子：
3.4
作者：
Tarrant, Emma;Riboldi, Gustavo P.;Waldron, Kevin J.
通讯作者：
Waldron, Kevin J.

Efficient zinc/cobalt inter‐replacement in northeast Pacific diatoms and relationship to high surface dissolved Co : Zn ratios

东北太平洋硅藻中有效的锌/钴相互置换及其与高表面溶解钴：锌比率的关系

DOI：
10.1002/lno.11471
发表时间：
2020
期刊：
Limnology and Oceanography
影响因子：
4.5
作者：
Kellogg, Riss M.;McIlvin, Matthew R.;Vedamati, Jagruti;Twining, Benjamin S.;Moffett, James W.;Marchetti, Adrian;Moran, Dawn M.;Saito, Mak A.
通讯作者：
Saito, Mak A.

Marine Synechococcus isolates representing globally abundant genomic lineages demonstrate a unique evolutionary path of genome reduction without a decrease in GC content

DOI：
10.1111/1462-2920.14552
发表时间：
2019-05-01
期刊：
ENVIRONMENTAL MICROBIOLOGY
影响因子：
5.1
作者：
Lee, Michael D.;Ahlgren, Nathan A.;Webb, Eric A.
通讯作者：
Webb, Eric A.

Competitive inhibition of cobalt uptake by zinc and manganese in a pacific Prochlorococcus strain: Insights into metal homeostasis in a streamlined oligotrophic cyanobacterium

DOI：
10.1002/lno.10935
发表时间：
2018-09-01
期刊：
LIMNOLOGY AND OCEANOGRAPHY
影响因子：
4.5
作者：
Hawco, Nicholas J.;Saito, Mak A.
通讯作者：
Saito, Mak A.

Minimal cobalt metabolism in the marine cyanobacterium Prochlorococcus

DOI：
10.1073/pnas.2001393117
发表时间：
2020-07-07
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
影响因子：
11.1
作者：
Hawco, Nicholas J.;McIlvin, Matthew M.;Saito, Mak A.
通讯作者：
Saito, Mak A.