Numerous microscopic studies have described the development of biofilm on surfaces immersed in marine waters. The biofilm development begins with the adsorption of dissolved organic matter followed by the colonization, attachment and growth of microorganisms, and adsorption of particulate matter.

Generally, it is also believed that bacteria are the most abundant microorganisms to colonize surfaces followed by microalgae, fungi and protozoa during the initial stages of fouling. This implies that the biofilm is rich in labile organic matter and can serve as an excellent nutrient source for the detritus or filter feeders.

Recently, a multi-parameter approach based on biological, chemical, biochemical and molecular level has been used to assess the development of biofilm on metal surfaces. Such a approach was helpful to better understand the dynamics, nature, nutritional value and sources of biofilm developed on surfaces. It appears that irrespective of the type of surface, the first step in the development of biofilm is the deposition onto surfaces of the degraded organic matter derived from biogenic and/or terrestrial sources. This is generally followed by high abundance of hexoses accompanied by low contribution from pentoses and deoxysugars suggesting the abundance of microalgae between days 5 and 10 following immersion. As the period of immersion increased, the relative abundance of ribose and rhamnose increased and that of glucose and fucose decreased suggesting the abundance of bacteria in the biofilm developed on metal surfaces at day 15 of the immersion period. This biofilm development based on above mentioned parameters is rather different than that was known earlier. Furthermore, although microalgae were abundant in biofilm, carbohydrates were not the most abundant constituents of total organic carbon. Carbohydrate-C and protein-C accounted for 7 to 30% of total organic carbon of the biofilm. That means 70 to 93% of the organic matter of the biofilm remained uncharacterized. Thus, biochemical characterization at the molecular level provides a better picture of biofilm development on surfaces immersed in aquatic environment.