科尔沁沙地生物结皮藻类的组成及生物量的变化规律

The algae composition and biomass characteristic of microbiotic crust in Horqin Sand land

科尔沁沙地生物结皮中蓝藻和绿藻共有23种,其中蓝藻15种占总种数的65.22%,绿藻8种,占总种数的34.78%。在不同类型的样地中,生物结皮藻类组成及分布也不同,流动沙丘表层的种类组成最少,固定沙丘藻结皮层的种类组成最多。这种现象表明,随着沙丘的固定,生物结皮的进一步发育,藻类的种类也随之增多。固定沙丘藻结皮叶绿素a含量明显高于半固定沙丘藻结皮叶绿素a的含量,并且在春季和冬季固定沙丘藻结皮叶绿素a含量极显著高于半固定沙丘藻结皮叶绿素a的含量(P<0.01),对于同种类型沙丘藻结皮藻类生物量在不同季节的变化则表现出夏、秋季藻结皮藻类生物量显著高于春、冬季(P<0.05)。藻结皮不同季节藻类生物量含量与当地季节降雨量和温度呈明显的正相关,因此科尔沁沙地降雨量与温度是影响藻类生物量的重要生态因子。

It was studied in Horqin Sand land that blue and green algae obtained from Biological Crusts contain 23 kinds.Among them,there are 15 kinds of blue algae（about 65.22%） and green 8 kinds of algae（about 34.78%）.Composition and distribution of algae vary with different kinds of sample field.The species composition of algal crusts plane have the least in semi-fixed sand and the most in fixed sand.This phenomenon indicates that the types of algae increase in pace with the fixing of sand and growing up of microbiotic crust.The content of fixed sand algae crust chlorophyll a is obviously higher than that of semi-fixed sand,especially in spring and winter（P〈0.01）.The variation of the same type of sand algae crust algae biomass in different season shows that algal crust biomass in summer and autumn is higher than that in spring and winter（P〈0.05）.The biomass of algal crust in different seasons had positive correlation with the local rainfall and temperature.So the rainfall and temperature of Horqin Sand land are the main ecological factors in affecting algae biomass.