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

项目摘要 项目描述和目标：本项目是对RFA任务的响应， 气候变化和有害藻华之间的联系项目3的目标是研究自然的作用， 有害藻华产生的细胞外次级代谢产物的命运背景下的衰减 和邻近的微生物群落。这项工作的重点是衡量气候变化对环境的影响， 与群体感应有关的微生物信号的衰减率;有害藻类毒素的变化 表达（重点是微囊藻毒素和类毒素）作为藻类培养物暴露于常见的 多物种信号自诱导物-2和酰基高丝氨酸内酯，细胞外毒素的降解， 水体和沉积物表面，并将埋藏毒素的沉积记录与过去进行对比 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、水解和沉积物- 催化过程）。有害藻类培养物将被询问是否存在内源性微生物 信号，以及它们对外源性微生物信号的加入的响应将被确定， 集中于表达的毒素的产量和类型。对藻毒素降解的动力学和产物进行了研究 根据多因素环境模拟实验（包括光化学、水解 和沉积物催化过程）。微生物信号、毒素和独特降解的浓度 将在德克萨斯州韦科湖（Lake韦科，TX）的天然水中测定这两种产品的含量，采样地点选择在 与项目2协商。有害藻华毒素的浓度也将在 210 Pb测年。最初的岩心研究将集中在韦科湖，以便比较210 Pb， 当地气象记录和藻类水华的历史记录。后续勘探沉积 将对从南卡罗来纳州一系列雨水蓄水池中提取的岩心进行分析， 已知偶尔会有有害的藻类大量繁殖，但没有定期监测。本项目的总体目标 是测量有害藻类的关键胞外代谢物的环境效应和持久性 在基线条件下和预测的气候变化结果下的水华。 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