The Study On Cyanobacteria Species Diversity And Ecology Of The Algal Crusts In Songnen Grassland

The Songnen grassland always has special ecological position and important economic significance. Recently, the scientists did a lot of researches on the vascular vegetation existed in this region, but they paid less attention to the widespread cyanobacteria. The cyanobacteria also have more important ecological functions, which is one of the essential components of the algal crust in this area. We selected the elementary biological soil crusts that subordinate to northeast normal university as the experiment matter in this research. We chose5kinds of vegetation types and a natural alkali spot as the experiment plots:Leymus chinensis community, Puccinellia tenuiflora community, Chloris virgata community, Artemisia anethifolia community, Suaeda corniculata community and Alkali spots.The cyanbacteria species composition of algal crusts was identified with the traditional morphology and molecular methods, the thickness and biomass of the algal crusts in difference vegetation types were also determined, and at the same time the weight degradation and the nitrogen contents were surveyed. The ecological functions of the algal crusts was researched as follows:the relationship between algal crusts and underground soil, including the temperature, water content, pH value, electrical conductivity.The results showed that the Microcoleus vaginatus and Nostoc commune are the dominant species in algae crusts in every experiment plots. The differences of thickness and biomass are statistically significant. The soil temperature, pH value and electrical conductivity in algae crusts plot is lower than that without algae crusts. The soil water content with algae crusts plot is more than that without algae crusts plot, but the differences of them were not statistically significant. The difference of degradation of weight and nitrogen in three kinds of algal crusts were affected by many factors, such as thickness and biomass.This study is a good supplement in the cyanobectiria species composition and ecology to this area and the grassland ecosystem. It also will make a big contribution to the biological soil crusts in arid or semiarid ecosystem.