Toxic Harmful Algal Blooms (HABs)

在过去的几十年里，出现了一系列新的有害藻华（HAB），并新发现了天然毒素;据认为，其中许多是沿海沃茨营养负荷增加和生态系统改变的结果，特别是在亚热带和热带海洋沃茨。据推测，有许多其他种类的藻类产生毒素，但这些毒素没有被识别，因为它们的浓度不足以对人类和其他动物造成问题。为了了解有害藻华的发展情况，必须在低浓度下研究这些物种成为有害藻华之前的种群动态。拟议研究项目的中心假设是，许多种类的甲藻，蓝藻和其他藻类产生的毒素目前没有被人类注意到，因为这些物种目前还没有密集到足以产生有害数量的毒素，或者它们位于人类与受影响食物网互动不多的海洋区域。由于流入海洋的营养物质不断增加，运输到新的地区，全球变化和不断变化的社区 然而，由于结构的复杂性，其中一些稀疏或未被注意的物种可能会在未来产生有害藻华。 这项拟议研究的目标是检查大量的藻类物种从亚热带和热带沃茨的生产各种类型的天然海洋毒素。利用遥感设施核心，大部分取样制度将以遥感数据为指导。遥感数据将特别有助于查明“水团”和锋面，从而优化取样制度。将测量温度、盐度、氧气、浊度、光照和营养物质。浮游植物群落将通过色素、流式细胞术、光学显微镜和物种特异性寡核苷酸探针来表征。与有毒藻类养殖设施核心合作，将确定和培养个别潜在的有害藻华物种。将通过红细胞溶血和离子通道活性测定来分析水、海洋表面微层和颗粒物（包括浮游植物）的样本中的毒素。显示毒性的样品随后将用前面提到的其他方法进一步分析。利用基因组学核心，DNA测序将用于确定物种之间的遗传关系，并将这些数据与产生的毒素类型进行比较，以确定可能的生态和进化关系。将开发新的物种特异性寡核苷酸探针，可用于快速定量 这些物种在海洋中。实地采样将主要在亚热带南佛罗里达沿海沃茨进行，但也在热带加勒比地区进行，利用调查人员使用的现有采样网络。这一取样将检查和量化毒素在亚/热带生态系统中的分布、毒素通过食物网的传播及其与产生毒素的物种的空间和时间相关性。此外，还研究了无毒种、产毒非赤潮种和赤潮种的种群动态。 比较有害藻华和非有害藻华物种对环境因素的反应，以确定它们之间是否有任何基本的差异，并阐明在亚热带海洋环境中产生毒素的任何可能的生态功能。

Over the past few decades, a range of new Harmful Algal Blooms (HABs) with newly discovered natural toxins have appeared; it is thought that many of these are the result of increased nutrient loading into coastal waters and altered ecosystems particularly in subtropical and tropical marine waters. It is hypothesized that there are many other species of algae produce toxins, but these toxins go unrecognized because they are not in high enough concentrations to cause problems to humans and other animals at the present time. To understand the development of HABs, it is important to study the population dynamics of species at low concentrations before they become HABs. The central hypothesis of the proposed research project is that many species of dinoflagellates, cyanobacteria, and other algae produce toxins that are not currently noticed by humans because those species are not dense enough at the present time to produce harmful quantities of the toxins, or they are in areas of the ocean where humans do not interact much with the affected food web. As a result of increasing nutrient fluxes to the ocean, transport to new areas, global change, and changing community structure, some of these sparse or unnoticed species could generate HABs in the future. The goal of this proposed research is to examine a large number of algal species from subtropical and tropical waters for the production of a variety of types of natural marine toxins. Using the Remote Sensing Facility Core, much of the sampling regime will be guided by remote sensing data. The remote sensing data will be particularly useful in identifying "water masses" and fronts so that sampling regimes can be optimized. Temperature, salinity, oxygen, turbidity, light, and nutrients will be measured. The phytoplankton community will be characterized by pigments, flow cytometry, light microscopy, and species-specific oligonucleotide probes. Working with the Toxic Algae Culture Facility Core, individual potentially HAB species will be identified and cultured. Samples of water, sea surface microlayer, and particulates (including phytoplankton) will be analyzed for toxins by red blood cell hemolysis and ion channel activity assays. Samples that show toxicity will then be analyzed further with the other methods mentioned earlier. Using the Genomics Core, DNA sequencing will be used to determine the genetic relationships among the species, and these data will be compared to the types of toxins produced to determine possible ecological and evolutionary relationships. New species-specific oligonucleotide probes will be developed that can be used to rapidly quantify the abundance of these species in the ocean. Field sampling will be conducted primarily in subtropical South Florida coastal waters, but also in the tropical Caribbean, taking advantage of existing sampling networks used by the investigators. This sampling will examine and quantify the distribution of toxins in the sub/tropical ecosystem, the propagation of the toxins through the food web, and their spatial and temporal correlations with the species that produce the toxins. In addition, the population dynamics of non-toxic species, toxin-producing non-HAB species, and HAB species will be compared to determine if there are any fundamental differences between HAB and non-HAB species in how they respond to environmental factors and elucidate any possible ecological function for toxin production in sub/tropical marine environments.