Basic research for solutions on global climate change using microbial loop

在日本静冈县的Sanaru湖，每年夏天都会出现聚藻球菌（小型浮游藻类）的循环繁殖。研究了有利于聚囊球菌生长的环境条件和原生生物对聚囊球菌的放牧损失。我们最后讨论了通过光合作用固定CO2的聚球菌和捕食聚球菌的异养鞭毛虫之间的食物链降低大气CO2浓度。氮的供应促进了聚囊球菌的生长。鞭毛虫对聚囊球菌的掠食损失与聚囊球菌的产生一致。因此，大气中的二氧化碳将通过含氮聚球菌和异养鞭毛虫之间的食物链被有效地消耗掉。

In Lake Sanaru, Shizuoka Prefecture, Japan, annual cyclic blooms of Synechococcus spp. (small planktonic algae) occur during summer. We studied on environmental condition favorable to growth of Synechococcus and grazing loss of Synechococcus by protists. We finally discussed the reduction of atmospheric CO2 concentration through food chain between Synechococcus which fixes CO2 through photosynthesis and heterotrophic flagellates which prey on Synechococcus. Growth of Synechococcus was stimulated by nitrogen supply. Grazing loss of Synechococcus by the flagellates agreed well with production of Synechococcus. Atmospheric CO2 thus would be effectively consumed through the food chain between Synechococcus with nitrogen supply and heterotrophic flagellates.