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Natural History I stepped off the stern into the frigid water of Barkley Sound. A sharp pain stabbed my forehead as the icy water assaulted my skull, like the kind of headache you get when you gulp too much ice cream. After a brief swim to the bow of the boat, my buddy and I descended the anchor line into the murky depths. Faint white blotches gradually materialized into giant Plumose Anemones as we approached the reef 15 metres down. I sometimes wonder why I endure the discomforts of these cold northern waters. But each time, the colour and diversity of life here rekindles my enthusiasm, and the discomforts fade into the background. Yellow, pink, red and lavender patches cover the entire surface of rock and sway in the surging current. Few places in the world can surpass the beauty of this undersea garden. With my face now just centimetres away from the reef, I can see the texture and forms of sponges, sea squirts and moss animals that cover the rock. Very few of these organisms are overgrown by other species. The sponge cannot physically remove organisms that settle on it, and yet its surface is clean. The same goes for the translucent blobs we call compound sea squirts. What's going on here? The ocean is full of larval animals and plants looking for a place to attach themselves. What prevents them from settling on top of each other? It turns out that many of these animals produce repellents, a kind of chemical defence. They cannot run away from their enemies, so they produce toxic chemicals that repel them. And many of these repellents have medicinal properties beneficial to humans. We have already discovered this phenomenon in land organisms. Most of you are familiar with the mould called penicillin that kills bacteria. Aspirin (ASA) comes from the willow tree. Many British Columbians know about the discovery of taxol -- which is used in treating cancer -- in the Yew tree of our own rain forests. Almost a quarter of all medical prescriptions originate from plants or micro-organisms. One of the arguments for preserving tropical rain forests is the potential for discovering more of these natural chemicals that can benefit humans. The same argument can be used for preserving the health of marine ecosystems - they can also be a source of medicines. In the sea, many of the attached organisms are animals rather than plants. Common marine animals such as sponges, sea squirts, hydroids, corals and sea anemones contain chemicals that repel predators. Scientists are only just beginning to assess the potentially useful molecules that may be present in marine species. In A Wealth of Wild Species, tropical biologist Norman Myers presents an impressive list of chemicals already isolated from these animals. An extract from octopus relieves hypertension. A Caribbean sponge produces a compound that acts against viral diseases. Chitosanase, an enzyme from shells of shrimps, crabs and lobsters, prevents some fungal infections. Didemnin, derived from sea squirts, appears to attack two classes of viruses: it is also reported to double the life expectancy of animals suffering from leukaemia. Extracts from three species of sea stars can resist one type of flu virus. A Caribbean sponge produces a compound, Cytarabine, that is effective against herpes and encephalitis, and treats leukaemia. One hundred and twenty species of sponges have been screened for bioactive chemicals -- almost half contain antibiotic substances. Paolin I, an extract from clams, oysters and abalone, arrests many harmful bacteria including streptococci. A related agent, Paolin II, inhibits herpes viruses and reduces some tumours. The list goes on. More than 2,000 species of marine life has been tested, and about 40% of the species with bioactive chemicals came from the corals and their relatives. These bioactive chemicals probably developed by random mutations. Because a bioactive repellent allowed an individual to survive longer and produce more offspring during its lifetime, a new genetic strain evolved. The potential chemical storehouse in the sea has barely been tapped. Some screening programs are under way in the northeast Pacific. Scientists sampled 40 marine sponges from the San Diego region, and found anti-microbial activity in 28 of them. A company in Washington State is testing marine species from the west coast, and east-cost marine species are being tested at a federal lab in Halifax. Ideally, once the compounds are identified, they would be synthesized artificially so that the species would not be endangered by over-harvesting. Humans can thus benefit from the millions of "clinical trials" that have taken place in nature. This potential storehouse is one of many reasons to preserve biological diversity in the sea. We poison our environment at our own peril. The spread of DDT and PCBs throughout the globe, thousands of kilometres from the original sources, should be proof enough that what we do locally can have global consequences. Human activities are causing the loss of species at a greater rate now than during any previous mass extinction, even more than during the extinction of the dinosaurs. Humans are the dominant animal on the planet. Unlike previous dominant species, we have the potential intelligence and the foresight to improve our chances of survival. But we must change how we affect our environment before it is too late. What guidelines should govern our behaviour? Renowned biologist and conservationist Aldo Leopold summed it up this way: "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise." Or as Norman Myers quotes from an international conference on the environment: "if we live as if it matters and it doesn't matter, it doesn't matter. If we live as if it doesn't matter and it matters, then it matters".
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