DIVERSITY OF EUKARYOTIC ALGAE

Algae are ubiquitous. They are the primary producers for all the oceans and seas, an area that covers 71% of the Earth's surface. Algae also occur in freshwater lakes, ponds and streams as well as on and in soil, rocks, ice, snow, plants and animals. In total, 40% of global photosynthesis is contributed by algae. The algae are tremendously diverse These are at least seven distinct phylogenetic lineages that arose independently during geological time and that evolved at different rates (based upon molecular clocks). Consequently, the algae in toto do not form a single, cohesive group, and they must be considered a polyphyletic assemblage. The red algal lineage has approximately 5000 recognized species (excluding nomenclatural synonyms. superfluous names, etc.) that are extant, and an estimated 500 to 15 000 new species remain to be described. The green algal lineage has approximately 16000 recognized extant species and up to 100 000 species that remain to be described. The chromophyte lineage has approximately 15 000 recognized extant species and from one to ten million species that remain to be described. The dinophycean lineage (primarily dinoflagellates) has approximately 3000 recognized, extant species and workers estimate that from 500 lo 8000 species remain to be described. The euglenophyte lineage has approximately 900 recognized extant species, and experts estimate that up to 1000 species remain to be described. The cryptophyte lineage is undergoing total revision and the numbers of species is very uncertain; perhaps 200 extant species are recognized and 1000 species remain to be described. The glaucophyte lineage has 13 recognized species, and perhaps several dozen species remain to be described. Since the 1960s, clonal culture followed by electron microscopic examination is often required before an alga can be identified or described as new. Recently, electron microscopy is being augmented by, or replaced by, gene sequence comparisons. Both electron microscopy and molecular sequencing are time consuming and expensive methods that slow the descriptions of new species. Time consuming methods for describing new algal species, a reduction in the number of algal systematists, a reduction in funds to support systematic research, and phycologically unexplored geographical areas act synergistically to hamper the rate of accessing algal biodiversity.