The role of heterotrophic bacteria in protecting cyanobacteria from hydrogen peroxide in coastal systems.

异养细菌在保护蓝藻免受沿海系统过氧化氢侵害中的作用。

基本信息

批准号：
1736629
负责人：
Gregory Dick
金额：
$ 87.41万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-01-01 至 2022-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736629&HistoricalAwards=false
关键词：
role heterotrophic bacteria protecting cyanobacteria

项目摘要

Toxic cyanobacterial harmful algal blooms (CHABs) are now a worldwide problem that poses dangers for humans and aquatic organisms including life-threatening sickness, beach closures, health alerts, and drinking water treatment plant closures. This project focuses on the basic science needed to understand interactions between the microorganisms present in CHABs and the chemistry of the lakes they inhabit. In particular, it will study the sources, fate, and effects of hydrogen peroxide, which is a potentially important control on the toxicity and species present within these blooms. This research will be conducted in Lake Erie, a source of drinking water for 11 million people that is threatened by CHABs annually. Results will be directly integrated into two water quality models that are widely used by water managers and other stakeholders. This project will support the training of two PhD students, including a first-generation college attendee, and undergraduate students from backgrounds that are underrepresented in the earth sciences. Research will also be integrated into outreach aimed at increasing diversity in the earth sciences by involving women and underrepresented minorities in K-12 as well as college and adult educational settings.The overall goal of this project is to determine the influence of hydrogen peroxide (H2O2) on cyanobacterial community composition and function in nearshore ecosystems. Preliminary results from Lake Erie show that dominant primary producers rely on heterotrophic bacteria to draw down H2O2 from transiently high environmental levels that are likely inhibitory to members of the cyanobacterial community. This suggests that H2O2 plays important and still poorly understood roles in aquatic microbial ecology. A combination of field sampling, experiments, and state-of-the art "-omics" will be used to test the overall hypothesis that H2O2 decomposition by heterotrophic "helpers" is an important determinant of microbial interactions and community structure and function. Lake Erie will be studied because (i) it is a model system for shallow coastal areas receiving high terrestrial nutrient runoff, (ii) it offers strong inshore-offshore gradients of light and nutrients for comparative studies, and (iii) existing sampling infrastructure, archived samples, and preliminary data can be leveraged. Field and laboratory experiments and measurements will be integrated to answer the following questions: Q1: What drives the temporal dynamics of H2O2 concentrations? Q2: Which enzymes and organisms are responsible for protecting the community via biological H2O2 decay? Q3: How does protection from H2O2 by helpers influence the composition and function of the community? The study will perform controlled lab experiments on cultures and on natural waters during different points of the bloom. Measures of H2O2 concentrations and rates of production and decay, along with supporting chemical and biological measurements, will be used to assess the major sources and sinks of H2O2. Molecular tools will be used to determine the pathways underpinning H2O2 decay and the effect of H2O2 on cyanobacterial community composition function. In parallel, impacts of varying H2O2 concentrations on growth rates of major cyanobacteria will be assessed experimentally. These experimental results will be placed into context through comparisons with the structure and function of microbial communities from field samples across spatial, temporal, and chemical gradients in this coastal ecosystem. The approach of integrating studies of H2O2 with "-omics" in natural systems is novel, and will advance our fundamental knowledge and understanding of the relationship between microbial community composition and function.

有毒蓝藻有害藻华 (CHAB) 现在是一个世界性问题，对人类和水生生物构成危险，包括危及生命的疾病、海滩关闭、健康警报和饮用水处理厂关闭。该项目的重点是了解 CHAB 中存在的微生物与其所栖息的湖泊化学之间的相互作用所需的基础科学。特别是，它将研究过氧化氢的来源、归宿和影响，这对于控制这些水华中存在的毒性和物种具有潜在的重要作用。这项研究将在伊利湖进行，该湖是每年 1100 万人受到 CHAB 威胁的饮用水源。结果将直接整合到水资源管理者和其他利益相关者广泛使用的两个水质模型中。该项目将支持培训两名博士生（包括第一代大学生）和来自地球科学领域代表性不足的本科生。研究还将纳入旨在增加地球科学多样性的外展活动，让女性和代表性不足的少数群体参与 K-12 以及大学和成人教育环境。该项目的总体目标是确定过氧化氢 (H2O2) 的影响）关于近岸生态系统中蓝藻群落的组成和功能。伊利湖的初步结果表明，占主导地位的初级生产者依靠异养细菌从短暂的高环境水平中吸收 H2O2，这可能会抑制蓝藻群落的成员。这表明 H2O2 在水生微生物生态学中发挥着重要但仍知之甚少的作用。将结合现场采样、实验和最先进的“组学”来检验总体假设，即异养“助手”分解 H2O2 是微生物相互作用以及群落结构和功能的重要决定因素。将研究伊利湖，因为（i）它是接受高陆地养分径流的浅海沿海地区的模型系统，（ii）它为比较研究提供了强大的近海和近海光和养分梯度，以及（iii）现有的采样基础设施，可以利用存档的样本和初步数据。将整合现场和实验室实验和测量来回答以下问题： Q1：什么驱动 H2O2 浓度的时间动态？ Q2：哪些酶和生物体负责通过生物 H2O2 衰变来保护群落？ Q3：帮助者对 H2O2 的保护如何影响群落的组成和功能？该研究将对不同花期时期的培养物和天然水域进行受控实验室实验。 H2O2 浓度、生成和衰减速率的测量以及支持化学和生物测量将用于评估 H2O2 的主要来源和汇。分子工具将用于确定 H2O2 衰变的途径以及 H2O2 对蓝藻群落组成功能的影响。同时，将通过实验评估不同 H2O2 浓度对主要蓝藻生长速率的影响。这些实验结果将通过与该沿海生态系统中空间、时间和化学梯度的现场样本中微生物群落的结构和功能进行比较来结合起来。将 H2O2 研究与自然系统中的“组学”相结合的方法是新颖的，将增进我们对微生物群落组成和功能之间关系的基础知识和理解。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Chlorophyll nitrogen isotope values track shifts between cyanobacteria and eukaryotic algae in a natural phytoplankton community in Lake Erie

DOI：
10.1016/j.orggeochem.2018.12.006
发表时间：
2019-02
期刊：
Organic Geochemistry
影响因子：
3
作者：
Jenan J. Kharbush;Derek J. Smith;McKenzie A Powers;H. Vanderploeg;D. Fanslow;R. Robinson;G. Dick;A. Pearson
通讯作者：
Jenan J. Kharbush;Derek J. Smith;McKenzie A Powers;H. Vanderploeg;D. Fanslow;R. Robinson;G. Dick;A. Pearson

Genotype and host microbiome alter competitive interactions between Microcystis aeruginosa and Chlorella sorokiniana