GAIA AND THE ART OF FIGHTING MARINE OIL POLLUTION

More than two decades ago, James E. Lovelock proposed the "Gaia" hypothesis: The biosphere of earth acts as a single organism trying always to maintain optimal conditions for its life, and is capable of manipulating nature to counteract against adverse environmental changes.
            This hypothesis has had many illustrious proponents (Lynn Margulis, for one), and at least as many illustrious opponents (Richard Dawkins, for one).
            The Gaia concept became thought fodder for some mystic minded persons and cults and thus lost a lot of credibility with time. But the concept is not wholly dead and in many circles remains as controversial today as it was yesterday. However, it seems to have gained a new friend in an environmental discovery which seems to fit snugly within its framework.
            While studying the oil pollution in the Arabian Gulf, researchers Dr Naser Sorkhoh, Professor Redha Al-Hasan and Professor Samir Radwan from Botany and Microbiology Department of Kuwait University, in collaboration with Prof. Thomas Hoepner of ICBM, University of Oldenburg, discovered the phenomenon of natural bioremediation of the oil-polluted Gulf as reported in NATURE, vol. 359, September, 1992.
            Before we go into details about their discovery, let us talk about marine oil pollution in general.
            Oil pollution in the sea is a constant threat to global ecology. This threat has become more and more acute in the last few decades which saw disasters leading to spillage of huge quantities of oil in the sea. Some of these well-known oil spill disasters are the Amoco Cadiz spill in 1978, the Ixtoc 1 disaster in 1979, the Exxon Valdez disaster in 1989 and the Braer spill at Shetland Isles in 1993.
            There are three general approaches for dealing with oil pollution problems: the mechanical, the chemical and the biological. For the best possible reclamation of polluted land and sea, a combination of all three methods is required.
            In sea, the mechanical approach involves skimming the oil off the water surface.
            Oil polluted areas can be sprayed with detergents and chemicals which can react with hydrocarbons and break them down to simpler, non-polluting compounds. This constitutes the chemical approach in fighting oil pollution. This approach has one drawback. The chemicals used can themselves cause pollution and prolonged and intensive use of these chemicals is likely to invoke the law of diminishing returns.
            The third front of attack on oil pollution involves employing biodegradation techniques using microorganisms. This process is called bioremediation.
            The principle is simple enough. There are numerous microorganisms found in nature, which have the capacity of ingesting hydrocarbons and excreting simpler, non-polluting compounds. The oil-polluted areas are seeded with a cocktail of such microorganisms, along with nutrients which can stimulate the growth of these microorganisms. Given sufficient number of microorganisms and sufficient time, this method goes a long way in helping towards removal of oil-pollution.
            But that is not all. There seems to be yet another way of fighting oil pollution: the nature's way.
            This was discovered, ironically enough, in the wake of the worst oil pollution of this century.
            This environmental crisis was precipitated by the Iraqi forces during their occupation of Kuwait, from 2nd August 1990 to 26th February 1991. At a conservative estimate, one million tons of oil was spilled due to the actions of the Iraqi forces in Kuwait. More than nine hundred Kuwaiti oil wells were deliberately damaged.
The oil released into the sea alone severely polluted about 770 km of the Kuwait and Saudi Arabia coasts.
            Rigorous efforts were made to rectify the pollution problem. It has now been fourteen years, but the seas and deserts are still not completely free of oil, though the pollution levels have been much reduced.
            This brings us to the discoveries of the researchers, Sorkhoh, Al-Hasan, Radwan and Hoepner, mentioned above.
            These scientists discovered the occurrence of an extensive growth of mucilagenous mats over oil layers in Saudi coasts. These mats covered the regularly inundated lower part of the oiled intertidal zone in vast sectors. The major components of these mats were marine blue-green algae called cyanobacteria. The predominant species of cyanobacteria found in these mats were Microcoleus chthonoplastes, Phormedium corium, Spirulina subsalsa and Oscillatoria sp.
           Cyanobacteria are photosynthetic. Many species of the cyanobacteria are highly tolerant to severe environments including high temperature and salinity. Some species of cyanobacteria can grow at temperatures up to 75 degrees Celsius. The cyanobacteria produce large amounts of mucilage.
Numerous non-photosynthetic bacteria were found embedded in these mats, the major ones being Rhodococcus sp. and Pseudomonas sp. Research showed that these bacteria are highly efficient in biodegrading the hydrocarbons found in crude oil.
            Immobilizing such oil degrading bacteria within the cyanobacterial mucilage protects them from being washed out in the open sea, and in addition, provides them with oxygen from the photosynthetic partner. Oxygen is essential for hydrocarbon biodegradation. Further, evidence   exists that the cyanobacterial component of the mats may also be involved in direct biodegrading of oil. Thus, in the microbial mats an unusually efficient oil-degrading system is being employed by nature to clean the seas of the oil-pollution and restore environmental balance.
            This natural phenomenon is very much in operation even today and is helping the human endeavors in fighting against marine oil pollution.

            Gaia???

Ahmed A Khan

 Ahmed is a Canadian writer who has written a book - Ghelenden .