EU-US ECOHAB. EC-NSF Cooperative Activity in Environmental Res: Mating Incompatibility Among Toxic and Non-Toxic Populations of Alexandrium: Ecological and Practical Implications

有害藻华（HABs）是美国和世界上一个严重且日益严重的问题。 在与有害生物有关的多种中毒综合征中，麻痹性贝类中毒可以说是全球范围内最广泛和最重要的。Alexandrum属内的甲藻（特别是tamarensis和minutum物种复合体）是美国和欧洲许多PSP爆发的原因。亚历山大草属物种的时空格局的几个特征值得注意。首先，在过去几十年中，由于自然和人为协助的扩散机制，两个复合体内的物种分布在地理上有所扩大。第二，在这些复合体中，某些物种既有有毒的，也有无毒的，有时这些物种在相对较近的地方开花。最近的研究结果表明，有毒和无毒的A。tamarense可以交配并产生休眠的孢囊，但是从这些孢囊中萌发的细胞在试图分裂时很快死亡。因此，至少对该物种的某些菌株存在生殖障碍。本项目的总体目标是调查亚历山大藻tamarensis和minutum物种复合体的有毒和无毒成员之间的交配相容性。这将涉及美国和欧盟合作伙伴在EC-NSF环境研究合作活动下直接合作的实验室和实地研究相结合。具体目标是：1）建立和表征来自美国东北部和欧洲的另外的有毒和无毒亚历山大藻培养物; 2）确定亚历山大藻的有毒和无毒菌株之间的交配相容性。tamarense和A.微小的; 3）确定区分有毒和无毒微小体的遗传标记; 4）开发确定嗜热细胞和包囊的有毒/无毒基因型的方法; 5）确定有毒和无毒A. minutum和A. tamarense菌株; 6）参加欧洲实地调查，绘制浮游生物和沉积物中Alexandrum种群的地图;以及7）利用生长率、放牧率和交配偏好数据来模拟各种入侵情景的结果，并评估引入无毒Alexandrum物种作为水华控制或缓解策略的潜力。拟议研究的科学价值是显著的，因为待探索的交配不相容性可以解释观察到的有毒和无毒亚历山大藻属物种在全世界的分布，并且直接与一种毒素类型入侵另一种毒素类型的领域的潜在成功有关，例如通过自然水流和风暴，或压载水排放。更广泛的影响也很重要。有害藻华对公众健康和有效利用沿海资源构成严重威胁。除了通过压载水排放或其他人为辅助手段的物种传播方面的实际影响，一种新的水华控制或缓解战略的潜在价值的社会将进行调查，从而无毒株Alexandrum可以引入到一个地区受到有毒爆发的方式类似于释放不育男性控制害虫。其他广泛的影响包括加强欧盟-美国的赤潮科学家网络，通过会议报告、科学出版物和大众媒体上的文章交流成果，以及培训和教育年轻科学家。在后一种情况下，来自美国和欧盟的学生和博士后研究人员将在PI的实验室工作，该项目得到外部奖学金，欧盟基金，内部WHOI基金（暑期学生奖学金，少数民族培训）和REU（本科生研究机会）的支持，并将提交提案。PI始终高度重视研究与教育的整合，该项目也不例外。

Harmful algal blooms (HABs) are a serious and growing problem in the US and the world. Among the multiple poisoning syndromes linked to HABs, Paralytic Shellfish Poisoning (PSP) is arguably the most widespread and significant on a global basis. Dinoflagellates within the genus Alexandrium (and in particular within the tamarensis and minutum species complexes) are responsible for many of these PSP outbreaks in the US and in Europe. Several characteristics of the temporal and spatial pattern of Alexandrium species are noteworthy. First, over the last several decades, the distribution of species within both complexes has expanded geographically as a result of natural and human-assisted dispersal mechanisms. Second, there are both toxic and non-toxic varieties of certain species within each of these complexes, and sometimes these bloom in relatively close proximity to each other. This latter observation is particularly noteworthy given recent results, which demonstrate that toxic, and non-toxic strains of A. tamarense can mate and produce resting cysts, but the cells that germinate from these cysts quickly die as they attempt to divide. A reproductive barrier thus exists for at least some strains of this species. The overall objective of this project is to investigate mating compatibilities among toxic and non-toxic members of the tamarensis and minutum species complexes of Alexandrium. This will involve a combination of laboratory and field studies in a direct collaboration between US and EU partners under the EC-NSF Cooperative Activity in Environmental Research. Specific objectives are to: 1) Establish and characterize additional toxic and non-toxic Alexandrium cultures from the northeastern U.S. and Europe; 2) Determine mating compatibility between toxic and non-toxic strains of A. tamarense and A. minutum; 3) Identify a genetic marker to distinguish between toxic and non-toxic minutum; 4) Develop methods to determine the toxic/non-toxic genotype of planktonic cells and cysts; 5) Determine mating selectivity of toxic and non-toxic A. minutum and A. tamarense strains; 6) Participate in European field surveys to map Alexandrium populations in the plankton and sediments; and 7) Employ growth rate, grazing rate and mating preference data to model the outcome of a variety of invasion scenarios and to evaluate the potential of introduced non-toxic Alexandrium species as a bloom control or mitigation strategy.The scientific merits of the proposed study are significant, as the mating incompatibilities to be explored may explain observed distributions of toxic and non-toxic Alexandrium species throughout the world and relate directly to the potential success of an invasion of one toxin-type into the domain of the other, such as through natural currents and storms, or ballast water discharge. The broader impacts are also significant. HABs represent a serious threat to public health and efficient utilization of coastal resources. In addition to practical implications with respect to species dispersal via ballast water discharge or other human-assisted means, a novel bloom control or mitigation strategy of potential value to society will be investigated whereby a non-toxic strain of Alexandrium could be introduced to an area subject to toxic outbreaks in a manner analogous to the release of sterile males to control insect pests. Other broad impacts include strengthening the EU-US HAB network of scientists, communicating results via conference presentations, scientific publications, and articles in the popular press, and training and education of young scientists. In the latter context, students and postdoctoral investigators from both the US and the EU will work in the PI's laboratory on this project, supported by outside fellowships, EU funds, internal WHOI funds (Summer Student Fellowships, Minority Traineeships), and REU (Research Opportunities for Undergraduates) support, for which proposals will be submitted. The PI has always placed a high priority on the integration of research and education, and this project will be no exception.