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了解的。 然而，球藻是许多淡水系统中极其重要的初级生产者。 在一些湖泊中，小球藻贡献了70%以上的固定碳。 据估计，多达100万种藻类仍有待发现。 这个问题可能是最严重的单细胞自孢子球藻，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，没有任何鞭毛虫阶段，并且不进行有性繁殖。 球形藻类，颜色为绿色，代表至少三种进化上不同的生物类型;黄藻（黄藻纲）、真鞭毛藻（真鞭毛藻纲）和绿色藻类（绿藻门）。 这些生物体不能通过光学显微镜彼此区分（即使在类水平上），因此通常被鉴定为“小绿色球”或（通常不正确地）小球藻属。 球形藻类大量存在于贫营养、中营养、富营养和营养不良的湖泊中。 然而，由于生物体尚未被鉴定，对球藻的研究范围非常有限。 研究人员通常认为，只有少数广泛分布的球形藻类。 这个合作项目（与北卡罗来纳州威尔明顿大学的Jeffrey Bailey博士合作，奖项0084197）正在研究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。 伊塔斯卡拥有丰富多样的湖泊、池塘和沼泽，非常适合这项研究。该项目包括几个具体目标，包括：（1）发现新的球藻分类群;（2）发展鉴定球藻的可靠遗传标准;（3）建立球藻参考标本库;（4）确定球藻在不同湖泊类型中的分布模式;（5）研究球藻的种群动态;（6）研究球藻的生物多样性。6）调查球状藻类的高级系统学; 7）调查球状分离物的生理耐受性;和8）开发鉴定标准和分布数据的数据库。 与其他藻类群体合作的其他藻类学家也将参与其中。这些研究应该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。 该项目将为有关球状藻类种群的新的、更现实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.