An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving, physical components of the environment with which the organisms interact, such as air, soil, and water. Oceans are the home to huge microbial populations and diversity (Stach et al., 2005; Sogin et al., 2006) and they live in every corner of the ocean and their habitats are diverse; they are distributed in open waters, sediments, associated with many organisms, estuaries, hydrothermal vents (Cevera et al., 2005). They are always involved in the important processes of the sea in promoting organic material transformation and mineralization in the sediments and overlying waters (Das et al., 2007). Microbial communities are structured by temporal and spatial variability of physicochemical and biotic parameters (Hewson et al., 2007).