"Integrating classical with phylogenetic taxonomic treatments in five genera of coccoid green algae (Chlorophyta)" The morphologically simple, unicellular, coccoid green algae (Chlorophyta) are an important and diverse group of photosynthetic eukaryotes. As primary producers, they occur abundantly in aquatic marine, freshwater, and brackish habitats. Coccoid green algae also can be found commonly in terrestrial habitats, and have been collected from some of the driest places on earth. In addition, coccoid green algae participate in symbioses with multicellular animals such as anemones, hydras, foraminifera, limpets, with unicellular protists, and with fungi, to form lichens. Coccoid green algae are important model organisms. Their close evolutionary relationship to embryophyte land plants makes them an ideal proxy for larger multicellular green plants in studies of cellular and molecular biology and genetics. Despite their ecological and biological importance, the coccoid green algae are very poorly studied, and our current taxonomic system for them is not reflective of their great biological diversity and evolutionary history. A team of three scientists, each an expert in the systematics of coccoid algae, will train students in systematic monographic research on five common genera of coccoid green algae. The genera, Chlorella,Bracteacoccus,Tetracystis, Chlorosarcinopsis, and Chlorococcum, will be targeted for a combination of morphological and DNA sequencing analyses. Both forms of data will be collected for all available culture collection isolates of each genus now held in public culture collections, and the Biotic Crust Project collection of desert algae. These data will be used to establish explicit phylogenetic species boundaries within the five genera, leading to formal taxonomic revisions. This work will train two Ph.D. students in all activities leading to a modern systematic treatment of coccoid green algae, from isolation and culturing, to light and scanning electron microscopy, to DNA sequencing, publication, and database production. The work will result in approximately 5000 nucleotides of new sequence data, from 4-5 different genes, collected from over 300 isolates of green algae. Monographic accounts of these algae will be published in phycological journals and incorporated into a web-accessible relational database that will connect species descriptions with images, geographic information, and related publications, thereby making the information readily accessible to the broadest of audiences. In addition, this work will provide a model for genus-level taxonomic work on other coccoid algae, expand our knowledge of the biodiversity of green algae, and serve the phycological community by establishing explicit generic and species boundaries for the numerous culture collection isolates for which no phylogenetic information exists. With a new emphasis on identifying "non-model" organisms for physiological and genomic studies, clarification of the taxonomy of these algae will also assist in the ability of other biologists to target specific species for these activities, thereby serving the broader biological community.
