Dissertation Research: Effects of propagule pressure and invasion resistance on establishment success of the toxic golden alga Prymnesium parvum

某些藻类可能会造成巨大的社会经济成本，因为它们会产生对环境中的其他物种以及人类有害的毒素。最近，一种金藻在全国和全球范围内的湖泊和水库出现有毒水华的频率和严重程度显著增加。在过去的十年里，这种物种在美国水道中的传播速度惊人地快。到目前为止，已有16个州证实，大量鱼类死亡可归因于金藻。该项目将研究入侵藻类如何在新环境中形成的两种假想机制。第一个假设是，富含营养的水会产生种类较少的微生物群落，从而降低对入侵的抵抗力。第二个假设是，入侵成功仅仅是分散到新栖息地的入侵者数量的函数。这项研究将在俄克拉荷马大学生物站的室外水箱中进行实验，以测试湖泊群落抵御金藻入侵的能力。实验处理将包括不同的金藻引入速度和群落中不同水平的微生物多样性，通过营养丰富和DNA测序进行量化。这项研究代表了对一般生态学理论在理解淡水微生物多样性方面的适用性的测试，但也为控制淡水有害藻类入侵提供了洞察。因此，该项目的成果与淡水生态系统的管理具有广泛的相关性。结果将通过科学报告和期刊出版物传播，也通过向当地社区和参观大学生物站的K-12学生和教师进行外联传播。本项目资助了一名研究生的毕业论文研究。

Certain species of algae can have substantial socio-economic costs because they produce toxins that are harmful to other species in their environments, as well as to humans. Recently, a species of golden alga has exhibited a significant increase in its frequency and severity of toxic blooms in lakes and reservoirs nationally and globally. The spread of this species has been surprisingly rapid through US waterways during the last decade. To date, sixteen states have confirmed massive fish kills attributable to golden algae. This project will examine two hypothesized mechanisms for how invasive algal species become established in new environments. The first hypothesis is that enrichment of water with nutrients creates less diverse microbial communities, which are then less resistant to invasion. The second hypothesis is that invasion success is simply a function of the number of invaders that disperse to the new habitat. This research will conduct experiments in outdoor tanks at the University of Oklahoma Biological Station to test the ability of a lake community to resist invasion by golden algae. The experimental treatments will consist of different rates of introduction of golden algae and different levels of microbial diversity in the community, created through nutrient enrichment and quantified using DNA sequencing.This study represents a test of the applicability of general ecological theory to understanding freshwater microbial diversity, but also provides insight into what controls freshwater harmful algal invasions. As such, the results from this project are of broad relevance to the management of freshwater ecosystems. Results will be disseminated through scientific presentations and journal publications, and also through outreach to local communities and K-12 students and teachers that visit the university biological station. This project supports the dissertation research of a graduate student.