1997 was declared the Year of the Reef as a way of bringing to the world's attention, the problems faced by these immense living structures. Called by some 'the rainforests of the seas' because of the diversity of life that they support, they were the subject of exhibitions, seminars and TV programmes throughout the year.

One of the reasons for including this in a diving related site is because Scuba divers are among those responsible for substantial amounts of damage to reefs in many parts of the world. Before getting into that and what we can do about it, here's a bit of background.....

Reefs are mainly found between 30 degrees north and south of the equator. They mostly form in shallow water, down to 30m. The main classifications include fringing reefs (common in Hawai'i), platform reefs (such as the Great Barrier Reef) and atolls (common in the Maldives and also Molokini in Maui County).

Coral reefs are made up of lots of small animals, or polyps, of about 0.5 cm or less. The different structures are the result of different species of coral aggregating to form fan, staghorn, brain coral etc. Reefs are made up of hard, or calcareous, corals binding together to form a limestone skeleton. Each polyp is like a small cup with tentacles and stinging cells surrounding the dual purpose orifice - 'dual purpose' because it is where food goes in and waste comes out.

Corals are very active and life on a reef is not easy. Coral species fight each other for the best positions, with access to light, warmth and plentiful food. Pitched battles take place in slow motion as one coral tries to take the place of another. Slower growing corals (1-2 cm a year), such as the brain and table types, are the more aggressive, which is why more of them are seen on established sites, whereas the faster, less aggressive types (10-15 cm a year) such as staghorn, are seen more on new sites.The structure provided by the coral skeleton provides a home to a complete ecosystem of plants and animals.

Most divers will be familiar with the sight of a coral head, surrounded by a sandy area and it is the coral head that teems with life, rather than the sand. In fact, about 25% of all marine species live in, or gain benefit from, coral reefs.What's the problem?It has been estimated that about 10% of all coral reefs are damaged beyond recovery. The rate of damage is increasing and on current trends, about 25% of reefs will be destroyed in the next 10-20 years.

The main sources of damage are pollution, agricultural runoff and over fishing, particularly where dynamite and/or cyanide fishing techniques are used. However, dive tourism makes a significant contribution to the damage in some parts of the world, including Hawai'i and the Red Sea.

As well as the direct effects of damage caused by divers touching reefs, dragging anchor chains through them or kicking sand over them and stifling polyps, there are the indirect effects of building dive resorts near reefs. The dust from building sites also stifles corals. And not all resort hotels are conscientious about what they pump into the sea.

The irony is that environmentally aware dive tourism can contribute much to the recovery of reefs, but that certainly requires better educated divers. So, what can be done?How to help

• The amount of money made by people taking from reefs: holidaymakers, dive tourists, pharmaceutical companies exploiting them for new drugs, is vast. Very, very little of that goes back into reef conservation efforts. If means could be found for diverting a small fraction of that money into caring for reefs, a lot could be done to give something back. So, ask what your dive shop, boat store, hotel or other coastal business is doing to save reefs. Let them know that you are an informed customer who cares about reefs.
• If you dive on a coral reef, don't touch it at all, and that includes by leaving guages dangling. And don't wear gloves, because they increase the temptation to touch.
• Avoid kicking up sand with your fins.
• Photographers in particular, need to avoid hanging on to the reef as a secure base for taking pictures.
• Don't take coral, whether it is dead or alive. Also don't buy any from local markets. If you feel up to it, explain to other divers or market traders why it is a bad practice.
• Don't use chemically enhanced fertilizers or pesticides, even if you are a long way from the sea. That's where they'll end up eventually.
• Volunteer for a reef cleanup.
• Support conservation organisations. Many of them have coral reef programmes and your financial support will make a difference.
• If this interests you (and I guess it does if you got this far), talk to other people about it.
• Don't put garbage or human waste in the sea, or leave it on the beach.
• Recycle. The effects are indirect, but accumulate over time.
• Only buy aquarium fish if they have been collected in an ecologically sound manner. In some places, the fish are stunned with sodium cyanide, to make catching them easier.
• Support the creation and maintenance of marine parks and reserves. Other divers tell me that Bonaire is one of the worlds best dive sites because of its marine reserve. .

We have to remember that we are just visitors to the reef - it is their home!