Collaborative Research: Species Discovery and Population Dynamics of Coccoid Algae in Itasca State Park, Minnesota

在所有真核生物中，微观藻类的多样性可能是最不为人所知的。然而，球藻在许多淡水系统中是极其重要的初级生产者。研究表明，在某些湖泊中，小球藻对固定碳总量的贡献超过70%。据估计，仍有多达100万种藻类有待发现。这个问题对于单细胞自孢子球藻来说可能是最严重的，在那里缺乏形态特征严重阻碍了物种识别。这些藻类几乎都是球形的，没有任何鞭毛阶段，也不有性繁殖。球藻是绿色的，代表了至少三种进化上不同的生物类型；黄叶植物（黄叶植物科）、赤叶植物（赤叶植物科）和绿藻（绿藻门）。这些生物不能通过光学显微镜相互区分（即使在分类水平上），因此通常被识别为“小绿球”，或（通常不正确地）小球藻。球藻大量存在于少营养、中营养、富营养和营养不良的湖泊中。然而，由于这些生物尚未被鉴定，对球藻的研究范围非常有限。研究人员通常认为只有少数几种广泛分布的球藻。这个合作项目（与北卡罗来纳大学威尔明顿分校的杰弗里·贝利博士合作，奖项0084197）正在调查明尼苏达州伊塔斯卡州立公园绿色自孢子球藻的多样性、种群动态和生理生态学。伊塔斯卡拥有多种多样的湖泊、池塘和沼泽，是这项研究的理想场所。该项目包括几个具体目标，包括：1)发现新的球藻分类群；2)建立可靠的球藻遗传鉴定标准；3)建立球藻参考采集库；4)确定不同湖泊类型球藻的分布格局；5)球藻种群动态研究；6)球藻高级分类学研究；7)球虫分离株的生理耐受性研究；8)建立识别标准和分布数据数据库。其他研究其他藻类群体的心理学家也将参与其中。这些研究将彻底改变对这些重要生物的时间分布、环境要求和种群动态的理解。这个项目将为新的、更现实的关于球藻种群的假设提供确凿的证据。

Among all eukaryotic organisms, the diversity of microscopic algae is perhaps the least understood. Yet coccoid algae are extremely important primary producers in many freshwater systems. It has been demonstrated that Chlorella sp. contributes over 70% of the total carbon fixed in some lakes. It is estimated that as many as 1 million species of algae remain to be discovered. This problem is probably most acute for the unicellular autosporic coccoid algae, where a lack of morphological characteristics has severely hampered species identification. These algae are all nearly spherical in shape, lack any flagellate stage, and do not sexually reproduce. Coccoid algae that are green in color and represent at least three evolutionarily divergent types of organisms; xanthophytes (Xanthophyceae), eustigmatophytes (Eustigmatophyceae), and green algae (Chlorophyta). These organisms can not be distinguished from each other (even at the class level) by light microscopy and thus have typically been identified as "little green balls", or (usually incorrectly) Chlorella spp. Coccoid algae are present in high numbers in oligotrophic, mesotrophic, eutrophic, and dystrophic lakes. However, because the organisms have not been identified, studies of the coccoid algae have been very limited in scope. Researchers have generally assumed that there are only a few widely distributed species of coccoid algae. This collaborative (with Dr. Jeffrey Bailey at the University of North Carolina, Wilmington, Award 0084197) project is investigating the diversity, population dynamics, and physiological ecology of green-colored autosporic coccoid algae in Itasca State Park, Minnesota. Itasca possesses a high diversity of lakes, ponds, and bogs that are ideal for this study. The project encompasses several specific goals, including the 1) discovery of new taxa of coccoid algae; 2) development of reliable genetic criteria for the identification of coccoid algae; 3) establishment of a reference collection of coccoid algae; 4) determination of the distribution patterns of coccoid algae in different lake types; 5) study of the population dynamics of coccoid algae; 6) investigation of the higher-level systematics of coccoid algae; 7) investigation of the physiological tolerances of the coccoid isolates; and 8) development of a database of identification criteria and distribution data. Other phycologists working with additional algal groups will be involved. These studies should revolutionize the understanding of the temporal distribution, environmental requirements, and population dynamics of these important organisms. This project will provide conclusive evidence for new, more realistic hypotheses concerning populations of coccoid algae.