求翻译：在微氧活性污泥中存在着好氧微生物，其正常的生长代谢消耗了溶解氧，使得反应器中存在一定体积的厌氧微环境，为厌氧微生物提供了生长空间。因此，在反应器中存在着由好氧微生物、兼性厌氧微生物及厌氧微生物组成的生态群落。是什么意思？

Exist in the micro-aerobic activated sludge aerobic micro-organisms, its growth and metabolism of normal consumption of dissolved oxygen, anaerobic reactor there is a volume of micro-environments, provided growth space for anaerobic microorganisms. Therefore, in the reactor there is by aerobic microbes in anaerobic, facultative anaerobic micro-organisms and microbial composition of ecological communities.