Abstract: Changes of biogenic silica (BSi) contents of lake surface sediments in ten lakes from northeastern, southwestern, northwestern and northcentral China were investigated in this study. The causes for the changes of BSi content and its spatial distribution characteristics were also studied via regional comparison among the ten lakes. The results showed that the mean contents of BSi in northwestern and northcentral China were lower than that in northeastern and southwestern China, possibly because lower temperature and less precipitation restricted the growth of algae, leading to less biomass production. However, the reasons for the higher mean values of BSi in the lakes from northeastern and southwestern China were different. The two lakes in northeastern China were eutrophic lakes and next to human settlements, so they may be substantially influenced by human activities. Although annual mean temperature in northeastern China was markedly lower, there were adequate nutrients for algae growing. Most lakes in southwestern China were oligotrophic lakes, thus the higher BSi values may be induced by the higher temperature and more precipitation.

Key words: aboveground biomass, net primary productivity, spatial pattern