Sea is a home to a wide range of
sessile organisms having larval dispersing stage in their life cycle. For these larvae successful colonization of a suitable surface is a must for commencement of adult stage. This calls for intense competition among various benthic species to utilize the available space. Hence all surfaces, natural and artificial exposed to
marine environment are liable to be colonized by these organisms. This colonization is referred to as
biofouling. It has got huge
economic implications on industries operating in marine environment. The most affected one is the
shipping industry. These organisms alter with the streamline shape of the ship thereby increasing the drag and reducing fuel efficiency. Biofouling lead to a drop in performance, stability and efficiency of marine off shore structures. Thereby, from economic prospectus these highly adapted marvelous creatures should be treated as enemies to be defeated.
Currently available remedy for biofouling is
antifouling paints having organotin based compounds as their active ingredient. The most effective ones are those which incorporate TBT. But the use of TBT has got environmental implications as its biocidal behavior is not confined to embattled organisms alone. The toxic effect of TBT was brought to light in 1980s . TBT was found to induce imposex in many gastropods like
Nucella lapillus,
Nassarius obsoletus and
Ocenebra erinacea. In mud snail
Ilyanassa obsolete, increased TBT level causes rise in testosterone levels increasing the chances of imposex. It reduces the number of marine nucleoid containing bacteria by 62%. In tunicate
Styela plicata exposure to TBT damages both male and female gametes, preventing egg – sperm interaction and thereby fertilization. To tackle these and many other ill effects of TBT, the International Maritime Organisation has proposed the complete prohibition of these organotin derivatives and other toxins in antifouling paint formulations after 2008. This has triggered extensive research though out the world to find an alternative of TBT that will not cause any threat to marine environment while serving as an effective antifoulant. An important area of research is to investigate and isolate such compounds from sessile marine invertebrates which maintain clean surface even when there is abundant fouling in their vicinity. Presence of antifouling compounds have been reported from many marine sessile organisms like sponges, soft corals, bryozoans, ascidians,
Sea weeds and sea grasses.
More abstracts about the Economic Importance of Biofouling