The effects of climate change on the natural attenuation and sedimentary record of harmful algal bloom toxins and microbial signals

项目总结 项目描述和目标：该项目是对RFA任务的响应，以审查关系 在气候变化和有害的藻类水华之间。项目3的目标是检查自然的作用 有害藻华产生的胞外次生代谢物去向的衰减 以及邻近的微生物群落。这项工作的重点是衡量气候变化对 与群体感应有关的微生物信号的衰减率；有害藻毒素的变化 微囊藻毒素和类毒素的表达作为藻类培养暴露于常见藻类的函数 多物种信号自动诱导剂-2和酰基高丝氨酸内酯，胞外毒素的降解 水柱和沉积物表面，以及埋藏毒素的沉积记录与过去的关联 气象条件。微生物信号降解的动力学和产物将根据 多因素环境模拟实验(包括光化学、水解性和沉淀物- 催化过程)。有害的藻类培养物将被询问是否存在内源微生物。 信号以及它们对外源微生物信号添加的响应将被确定，特别是 重点关注所表达的毒素的产量和类型。藻毒素降解的动力学和产物为 基于多因素环境模拟实验(包括光化学、水解性 和沉淀物催化过程)。微生物信号、毒素和独特降解的浓度 这两种产品都将在德克萨斯州韦科湖的天然水中进行检测，采样地点选择在 咨询项目2。有害藻华毒素的浓度也将在#年确定。 沉积物岩心用210Pb测年。最初的核心研究将集中在韦科湖，使比较210铅， 当地气象记录和藻类水华的历史记录。随后勘探的沉积物 将对从南卡罗来纳州一系列雨水滞留池中取出的岩芯进行分析，这些池子 已知偶尔会出现有害的藻类水华，但没有进行常规监测。本项目的总体目标 是测量对有害藻类至关重要的胞外代谢物的环境影响和持久性 无论是在基线条件下还是在气候变化预测的条件下，都会出现水华。 1

PROJECT SUMMARY Project Description and Objectives: This project is responsive to the RFA mandate to examine the relationship between climate change and harmful algal blooms. The goal of Project 3 is to examine the role of natural attenuation in the context of the fate of extracellular secondary metabolites generated by harmful algal blooms and adjacent microbial communities. This is done with a focus to measuring the effects of climate change on the attenuation rate of microbial signals involved with quorum sensing; changes in harmful algal toxin expression (focusing on microcystins and anatoxin) as a function of algal culture exposure to the common multispecies signals autoinducer-2 and the acyl homoserine lactones, degradation of extracellular toxins in the water column and at sediments surfaces, and correlating the sedimentary record of buried toxins with past meteorological conditions. The kinetics and products of microbial signal degradation will be determined based on multifactorial environmental modeling experiments (including photochemical, hydrolytic and sediment- catalyzed processes). Harmful algal cultures will be interrogated for the presence of endogenous microbial signals, and their response to the addition of exogenous microbial signals will be determined, particularly focusing on the yield and type of toxin expressed. The kinetics and products of algal toxin degradation will be determined based on multifactorial environmental modeling experiments (including photochemical, hydrolytic and sediment-catalyzed processes). The concentration of microbial signals, toxins, and distinctive degradation products of both will be determined in natural water from Lake Waco, Waco TX with sampling sites chosen in consultation with Project 2. The concentration of harmful algal bloom toxins will also be determined in sediment cores dated using 210Pb. Initial core studies will focus on Lake Waco, enabling comparison of 210Pb, local meteorological records and historical records of algal blooms. Subsequent exploratory sediment analyses will be performed on cores withdrawn from a series of storm water retention ponds in SC that are known to have occasional harmful algal blooms but are not routinely monitored. The overall goal of this Project is to measure the environmental effects and persistence of extracellular metabolites critical to harmful algal blooms at both baseline conditions and those predicted as a result of climate change. 1