In a word, the sea is earth's life-support system. The services rendered are so fundamental that most of us who live here tend to take them for granted. In the past century without much thought about the consequences, we have removed billions of tons of living creatures from the sea and added to it billions of tons of toxic substances. Fish, whales, shrimp, clams and other living things are regarded as commodities, not as vital components of a living system upon which we are utterly dependent.

When our numbers were small -- about 100 million 5000 years ago -- we could do little to harm the ocean's ancient ecosystems. Even by 1800 when our population had swelled to one billion, the impact of humankind on the sea was insignificant. By mid 1980s our population had ballooned to five billion. At the same time the catch of ocean wildlife peaked in 1989. Since then because of environmental awareness, the annual catch has declined. Yet, amazingly, under present "freedom of the seas" policies, even species once safe in remote parts of the deep sea are considered fair game, although not much is known about how many there are, how they live or what other values they have to humankind.

Deep sea exploitation wreaks havoc not only on one kind we want to net, but on others too. When we lure squid from the depths of ocean with bright lights, we snare millions of tons; our brief bonanza may doom not only the squid but also other fish, birds, marine mammals and other members of ocean communities that depend on squid for food. While certain kinds of krill, crab, cod, squid, herring, halibut, haddock, pollack, tuna and many other commercially sought after species may exist in "enormous" numbers, there is nothing to support the notion embraced by some that there are "surpluses" in nature just waiting to be extracted at will. Rather, wild populations, like the variations in the life on Earth, have good times and bad, the prosperous years serving as a cushion against leaner times. When we destroy the large numbers, we destroy the population's insurance against disease, poor weather, short rations and other natural ups and downs.

Curiously, no one really knows what the consequences will be of over fishing or ocean dumping, and incredibly little is being done to find it out. In recent years, observations from ships, submersibles, satellites and spacecraft, have yielded staggering discoveries: the existence of 65,000 km of underwater mountain ranges, knowledge of plate tectonics and the grand earth processes that drive the shifting of continents, the presence of the largest concentration of volcanoes on earth, and the profound important links between ocean currents and climate, weather and periodic phases of global warming and cooling.

In a sense, we are plundering the sea. Giant high-tech vessels roam the world's waters, scooping up their once bottomless bounty. Environmental activists call the vessels the "strip miners of the sea". Oceanologist liken many of them to plows that rip open the sea bottom. When they sail into unauthorised areas governments call them "pirates". These ships, trailing nets at least a kilometre long capable of hauling up 400 tons of fish in a single gulp, are blamed for an assault on worldwide fish stocks that could do what once was thought impossible: wipe out whole species of marine wildlife. Alarmed scientists of the World Conservation Union have added more than 100 species of marine fishes to the group's "Red List of Threatened Animals" including the familiar ones like sharks, tuna, coral-reef fish and sea horses.

Warns Greenpeace, the international environmental organisation: "For the first time in this century, world marine fish catches are declining". Many of the world's formerly productive fisheries are seriously depleted, and some have collapsed due to overfishing. The present state of the sea is alarming. "Dead Zones" -- layer of water devoid of wxygen and tens of thousands of square kilometres in size -- are spreading rapidly from river estuaries that pour human wastes and toxins into the sea. The factory ships are marvels of modern fishing technology equipped with sophisticated fish finding sonar, spotting aircraft and precision satellite based navigation leaving nothing to luck. Tens of thousands of tons of fish are swept into city-size nets and brought aboard for conveyor belt sorting, filleting and freezing.

Ocean pollution as evidenced by coral damage goes on unabated. Researchers found that environmental stress caused bleaching of the coral -- turning pale or completely white. Among the most badly affected areas: the Seychelles, the Maldives and the Coast of Indian sub-continent and its surrounding islands. Marine biologist R Soundararajun and his research team of the Central Agriculture Research Institute (CARI) in Port Blair, the capital of Andamans have found to their total shock that most severe and extensive bleaching of corals have occurred over the area they surveyed. Researchers opine that recovery from such dangerously high mass bleaching of corals will be delayed or impossible if the impact from pollution, overfishing and other human activities are not stopped or controlled.

Like tropical rainforests coral reefs are among the world's most biological diverse and productive ecosystems. They are a source of bioactive compounds for medicine. On the other hand economy of many countries is dependent on sea wealth and corals. Maldives' economy, for example, is driven by reef fishing and tourism, which accounts for 45 percent of its GNP. The spectacular and varied marine life around coral reefs attracts seven million sport divers around the world. "When corals die, reefs get degraded, shores are affected, fishes die, tourism dollars dry up", says Samir Acharya, of the society for Andaman and Nicobar Ecology, a non-governmental organisation.

Says Philippine marine researcher Laury Raymundo: Reefs offer refuge for many fish at different stages of their lives. Indonesia and the Philippines are places where reefs are most at risk, notes a study by the World Resources Institute. The annual potential fish yield from coral reef is estimated at nine million tonnes -- about 10 percent of the global catch. In the developing world reef associated fisheries provide a quarter of the seafood consumed. By forming natural barriers reefs protect seashores from the brunt of strong waves and storms. And their degradation will hurt coastal communities which account for more than two-thirds of the world's population. One might have noticed the severe erosion which has already struck sections of the Sri Lanka coast where reef structures were heavily mined in the prolonged civil war in that country. Some estimates of the economic damage beginning from 1998 Indian ocean bleaching that rise upto $700 million a year will total upto $8 billion in the next 20 years.

That's why solutions will require enormous organised effort on a global scale -- to reduce heat-trapping green house gases, halt unsustainable logging and adopt environmentally responsible habits. Business as usual is a formula for disaster. That was the call of the World Environment Day. After six months that still echoes the message of reducing sea pollution shouldn't we pay heed yet?

Md Asadullah Khan is a former teacher of Physics and Controller of Examinations, BUET.