Despite the overhanging plumes of soft coral and multitude of brightly coloured reef fish swarming around me, my attention is frequently diverted away from the wall and outward to the blue water. You never know what could be passing.
Today I am lucky. I glance up to see a manta ray flying lazily above, circling and feeding on the rich water washing across the reef. I swim away from the wall and ascend slowly toward the manta. Just as curious about me as I am about it, the manta descends and circles closer and closer until one wingtip brushes through my exhaust bubbles and it flits away.
Diving on a coral reef is always a wonderful experience, but it is the occasional special encounter like this that makes it really worthwhile. To tell the truth it had been a few years since I had dived in the Red Sea, I had been concentrating on locations further afield. But when I got back to it I was delighted by the quality of the diving; dense hard and soft corals and teeming with a huge variety of fish - equal to anywhere else I had dived.
Geologically the Red Sea is a continuation of the Great African Rift Valley, a north-south crack thousands of miles long in African continent. Surrounded by desert, low rainfall ensures exceptionally clear waters that combine with strong sunlight to provide an ideal environment for coral growth.
Corals are colonial animals, each individual polyp is an animal in its own right. They live in symbiosis with algae contained within the cells of the coral. In clear water the algae lives by photosynthesis - just like any other plant. The coral feeds on the algae and on nutrient filtered from the surrounding sea water. The algae in turn feeds on the corals' waste products.
The reef structure is built by coral polyps secreting a limestone skeleton. Although a slow process, over hundreds of thousands of years the skeletons of dead corals built one on top of the other to produce the towering walls of coral that make such fantastic dive sites. Coral growth and reef life is most prolific just below the surface where the sunlight is strongest. The top few metres of a coral wall frequently grow outward to overhang the older corals below. As you descend below the surface teeming clouds of bright orange antheas will surge in and out of the reef in chaotic formation, pecking at minute specks in the water.
Life on a coral reef ranges right down to the macro level. For a change from the big scene get your mask as close as possible to a small area of reef and study it in detail. It may take a while to spot them, but with dedication you will see gobies, shrimps, pipe fish and other minute reef creatures.
Coral reefs are a threatened environment. They suffer pollution from heavy industry and towns, shore development, over fishing and increasing numbers of divers. We can do our bit by being careful how we treat the reef, maintaining good buoyancy control and avoiding touching the corals. Many flights to Red Sea destinations now show a video by the Marine Conservation Society about good diving practices on coral reefs.
A few years ago careless anchoring of diving and fishing boats used to do appalling damage to the reef. This is all changing with local crews are now being careful in their placement and retrieval of anchors and using mooring buoys where they are available. There still remains the occasional rogue, and the best way to pull such boats in to line is with polite but firm pressure from us, the tourists their livelihoods depend on.