ABSTRACT

This chapter explains a detail description of the microbial community structure and dynamics occurring in various water environments, their survival, and role in the biogeochemical cycle. Aquatic microbiology is the study of microscopic organisms, namely, bacteria, archaea, viruses, and fungi, and their relation to other organisms in this entire aquatic environment, that is, organisms living in fresh or saline water ecosystems. A detailed study on microbial diversity of the aquatic ecosystems is essential for monitoring and anticipating their major activities and sustainability. The chapter presents microbial community structure and composition of the diverse aquatic ecosystem and the effect of contamination on the aquatic microbiota and a broad overview of groundwater, estuaries and lakes, drinking and wastewater microbial structure. The freshwater environment is broadly classified as lentic and lotic systems. Natural water bodies are in constant contact with rocks and sediments having different composition of mineral and compounds; therefore, the water inevitably gains a specific composition.