Microalgae of the Lanzhou (China) Cryptogamic Crust

Abstract
Cryptogamic crust was collected near Lanzhou, central China, in April 1986 before the start of the monsoon rains, which average 358 mm annually. The site lies on windblown loess at an elevation of 1556 m, where minimum January temperatures average — 14°C and maximum July temperatures average 29°C. The crust was analyzed for microalgae and cyanobacteria. Eleven organisms were isolated and described. Eukaryotic algae included two unicellular forms, Bracteococcus sp. and Myrmecia sp., and one filamentous branched alga, Moncilia sp., which was the largest algal component of the crust. Cyanobacteria included homocystous Oscillatoria williamsii an LPP group B isolate, and Phormidium sp., and heterocystous Nostoc spp., Anabaena sp., and Tolypothrix sp. The Lanzhou crust lacked the genus Microcoleus found in the western United States, Argentina, and Hungary, yet contained the genus Oscillatoria found in Argentina and India. The diversity of the Lanzhou crust composition indicates some potential for N2 fixation and moisture retention.