Fungi, particularly those in the class Euascomycetes, are important decomposers of large particulate organic matter in freshwater habitats, and hence are important intermediaries in energy flow and chemical cycles. Despite evidence of their importance, little information exists regarding their taxonomic identities and abundance in various types of freshwater habitats throughout North America and the rest of the world. As part of an ongoing survey of freshwater eascomycetes along latitudinal gradients, Dr. Carol Shearer of University of Illinois will collect, identify and isolate freshwater euascomycetes from a variety of aquatic habitats. Collections will be made in geographical areas rich in lakes and in tropical areas in Central and northern South America. This survey is organized around two broad conceptual areas: (1) the relationship between latitude and species diversity and composition, and species distribution patterns; and (2) the evolutionary relationships among terrestrial, freshwater and marine euascomycetes. Collections and cultures will be used to answer the following questions: (1) What species comprise the freshwater euascomycetes? (2) What is the relationship between latitude and species distribution patterns, species richness, and taxonomic composition at the species level and above? (3) Does species composition differ in lakes and rivers in the same geographical area? (4) What is the nature and degree of morphological and life cycle adaptation of freshwater euascomycetes to aquatic habitats? (5) How do the freshwater euascomycetes differ taxonomically from their terrestrial and marine counterparts? Products of this study will include: specimens, cultures, and gene sequences of freshwater euascomycetes; descriptions of new genera and species; an illustrated species monograph with an interactive key for their identification available on the WWW; and improved understanding of the relationships among sexually and asexually reproducing euascomycete species. Resulting cultures will be screened for production of new, biologically active chemicals and fungal cultures will be made available to other scientists for systematic, developmental, physiological, molecular, and ecological studies. A Colombian postdoctoral scholar will participate in the research, along with undergraduate students at the University of Illinois.
