TROPHIC AND NUTRIENT DYNAMIC ASPECT OF AQUATIC MICROBIAL ECOLOGY

Abstract

This paper gives a chronological review on our understanding in the role of heterotrophic bacteria in trophic and nutrient dynamic aspects of aquatic microbial ecology. Traditionally, the role of  heterotrophic bacteria was known as decomposer only. Later studies revealed that bacteria could be the food for several grazers especially, nano-, micro-  and mesozooplankton. Now, it is clear that heterotrophic bacteria channel the energy and matter to higher trophic level via microbial and metazoan food chains. Previously it was argued that dissolved organic carbon (DOC) is the prime limiting factor for fueling the energy and nutrient in aquatic ecosystem. However, emerging experimental evidences suggest that enrichment of plant nutrients such as phosphorus (P) stimulates bacterial growth. These suggest accumulation or organic carbon and other important nutrients in aquatic ecosystem, which are funneled in presence of limiting nutrients phosphorus. Moreover, recent studies showed that material transfer efficiency from bacteria to higher trophic level may depend on species composition of mesozooplankton. These discoveries established that bacterial primary production contributes substantially in secondary production, implying that contrasting to their tiny form bacteria play much important role in trophic and nutrient dynamics aspects of aquatic ecology. Key words:  Heterotrophic bacteria; Trophic dynamics; Nutrients; Mesozooplankton DOI: 10.3126/eco.v17i0.4097Ecoprint An International Journal of Ecology Vol. 17, 2010 Page: 9-16 Uploaded date: 28 December, 2010