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

项目概要 项目描述和目标：该项目响应 RFA 的要求来检查关系 气候变化和有害藻华之间的关系。项目 3 的目标是检验自然的作用 有害藻华产生的细胞外次生代谢物的命运减弱 和邻近的微生物群落。这样做的重点是衡量气候变化对 与群体感应相关的微生物信号的衰减率；有害藻类毒素的变化 表达（重点关注微囊藻毒素和赤霉素）作为藻类培养物暴露于常见物质的函数 多物种信号自诱导子 2 和酰基高丝氨酸内酯，细胞外毒素的降解 水柱和沉积物表面，并将埋藏毒素的沉积记录与过去联系起来 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）。将询问有害藻类培养物是否存在内源微生物 信号，以及它们对添加外源微生物信号的反应将被确定，特别是 重点关注表达的毒素的产量和类型。藻毒素降解的动力学和产物将是 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、毒素的浓度和独特的降解 两者的产物都将在德克萨斯州韦科湖的天然水中进行测定，采样点位于 与项目 2 协商。有害藻华毒素的浓度也将在 使用 210Pb 测年的沉积岩芯。最初的岩心研究将集中在韦科湖，以便对 210Pb、 当地气象记录和藻华历史记录。随后的勘探沉积物 将对从南卡罗莱纳州一系列雨水滞留池中取出的岩心进行分析，这些池子是 已知偶尔会出现有害藻华，但并未进行常规监测。本项目的总体目标 是为了测量对有害藻类至关重要的细胞外代谢物的环境影响和持久性 在基线条件和气候变化预测的条件下都会出现开花现象。 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