The ocean: treasure trove . . .
The sea, which covers around 70 per cent of the earth's surface, is home to millions of fish, crustaceans, mammals, microorganisms, and plants. It is a vital source of food for both animals and people. Thousands of birds rely on the sea for their daily food supplies. Fishermen throughout the world catch over 90 million tonnes of fish every year, and in many developing countries, fish is the principal source of protein.

But the oceans are in a bad way. People have treated the sea as a dumping ground for thousands of years, offloading rubbish, sewage, and - more recently - industrial waste. Marine pollution frequently originates on land, entering the sea via rivers and pipelines. This means that coastal waters are dirtier than the open seas, with estuaries and harbours being especially badly affected. Additional pollution is actually created at sea by activities such as dredging, drilling for oil and minerals, and shipping.

Defining Marine Pollution

For close to thirty years, most academics studying the phenomena of marine pollution have adhered to a definition developed by a UN body, the Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP), who define it as the...

"Introduction of man, directly or indirectly, of substances or energy into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hazard to human health, hindrance to marine activities including fishing, impairment of quality for use of sea-water, and reduction of amenities."

The definition has two important qualities.

First, it is action oriented. Marine pollution is conceptualized as a human activity, thereby omitting all natural activities that could potentially have damaging effects on the ocean eco-system. So, for example, earth quakes or volcanic eruptions that emanate from the ocean floor and subsequently damage or change already existing ocean eco-systems would not be considered pollution.

Second, the definition is amenable to measurement. Marine pollution is harmful, and its danger can be identified in a variety of ways. For example, it is easy to see the deleterious effects that oil spills have on the sea birds and mammals that happen to run into them. Scientists likewise can readily identify various toxic substances found in the marine environment, measure their quantities, and provide estimates of their potential danger for the health of both marine life and humans.