The importance of marine microbes and their relation to the productivity of the deep sea.

A review of: Das, S., Lyla, P and Khan, A. 2006. Marine microbial diversity and ecology: importance and future perspectives. Current science. Vol 90. No 10.

The largest habitat biospheres on earth provides the largest living space for organisms, especially for marine microbes. the term microorganism encompasses a wide variety of organisms including bacteria, viruses, protists and fungi. the deep sea is a unique and physically extreme environment. Barotolarent bacteria from depths of 500m were first discovered by certes, 1983. It thought that these microbes may exist in a state of suspended animation. deep see expeditions to work on deep sea microbiology undertook by Zobell 1952, stated that these heterotrophic bacteria utilize the abundant organic carbon or dissolved organic matter in a threshold concentration. These microbacterial split refractory polymeric substances, and further monomeric and oligomeric molecules to either the bacterial metabolism or the dissolved organic matter (DOM) pool. The deep sea bacteria are therefore efficiently adapted to extreme oligotrophy and the activity is mainly limited by substrate availability. Bacteria have adapted themselves for life in the extreme marine environment. the bacteria require high levels of Na+. This is vital for maintaining the osmotic environment for protection of cellular integrity.

The role of bacteria within the marine environment.
heterotrophic bacterial functions promote organic degradation, mineralisation and decomposition, and adds to the release of dissolved organic and inorganic substances. This organic matter which is mainly derived from primary producers, is recycled so these are again available for primary producers. These heterotrophic bacteria make up the bulk of the microbial populations inhabiting the water column. They are also responsible for the production of organic matter and carbon dioxide.
the study concludes that marine micro-organisms are able to breakdown all natural organic compounds into the compounds they originated from. The breakdown of protein takes place by proteoytic bacteria e.g. pseudomonas. cellulose within the ocean is mainly broken down by cellolytic bacteria e.g. cytophaga, chitin. This is then synthesised by some marine organisms e.g. cell wall of chlorophytes, extracellular material from algae and exoskeleton and molts from copepods.
The study also highlights the role that microbes play in the formation of sediment. The total amount of organic matter gradually decrease over time within the sediment, the structure of which therefore changes. It highlights the point that the bacteria will colonize suspended particles, changing their size, shape and therefore the sedimentation rate.
secondary metabolites. These are produced during the idiophase of microbial growth. One excellent example of a secondary metabolite only found in the marine environment is the production of antibiotics by marine bacteria.