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

Marvin W. Fawley and Karen A. Phillips

Phycologists estimate that as many as 1 million species of algae remain to be discovered and named. 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 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 round green things”, “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 project will investigate the diversity and population dynamics 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. This project will encompass 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) development of a database of identification criteria and distribution data. We will also work to involve other phycologists working with additional algal groups.

The first stage of this project will involve the isolation and identification of new species of coccoid algae. Samples will be collected from 10 sites over a one year period. Coccoid algae will be isolated from these samples and each isolate will be characterized by ribosomal RNA sequence-based techniques. These molecular characters will overcome the scarcity of morphological characters in these organisms. Over 100 new species of coccoid algae are expected from the Itasca Lakes. New species collected during this study will provide a more complete estimate of the biodiversity of coccoid algae and should result in the establishment of new genera, families and orders of coccoid algae.

In the second stage of the project, the population dynamics of the coccoid algae will be investigated by repeated sampling from the 10 sites for two consecutive years. Coccoid algae will be identified and enumerated using ribosomal RNA based techniques. These studies should truly revolutionize our 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.

Fawley-Phillips website on coccoid algae at the Arrowwood National Wildlife Refuge, ND: http://www.ndsu.nodak.edu/instruct/fawley/coccoids/