Posted by rebecca southam on 00, 2004 at 00:49:18:
In Reply to: Bubble trouble posted by Jamie Walker on 00, 2004 at 18:50:23:
: I bet as divers you are all aware that it is inadvisable to touch corals on reefs. I also bet that most of you know this is because you may damage the corals in doing so. : What we may not be told during our diver training is that as divers, we pose one of the most important threats to coral reef well-being. : For my undergraduate degree, I carried out research into the causes and effects of coral reef damage with a specific interest in diver damage. It was found that amongst the many man-mad threats to coral reefs, divers may cause significant damage if they are not aware of their underwater surroundings. The main findings of my work were that divers my have three types of contact with a coral reef - Accidental contact, Incidental contact and Indirect contact. Incidental contacts are contacts made 'on purpose' i.e. to prevent from banging into the reef or holding on when taking a photo. These types of contacts are the least damaging, as long as the diver is not touching live coral and they are not under an overhang. If the diver is under an overhang (or at the entrance to a cave)the exhaled air bubbles may cause significant damage to the coral reef in two ways: : Other indirect contacts such as wash from fins or hands may also damage the coral. The wash of your fins kicks up settled sediment which then re-settles on the coral polyps and effectively 'suffocates' the coral. Corals do have mechanisms to counteract this but increased levels of sediment can adversely affect the corals health. In some cases, fin wash may not be so significant as strong currents can have the same effect on sediment. : Some measures are being taken to try to reduce the numbers of diver contacts with the coral reefs of the world. For example the PADI Project AWARE video is very good but does not mention bubble damage. Other schemes, such as the one run by the Hurghada Environmental Protection Agency (HEPCA) in the Red Sea aim to educate people about diver impacts, but more must be done. : I questioned dive tourists in Indonesia, one of the most pristine dive areas in the world to see what they wanted from coral conservation and 100% of respondents wanted their future children to be able to experience the reefs they had experienced. I am sure that you want the same from your children in years to come. : If you would like any further information about my research, please feel free to email me. : Jamie Walker
: We are all told, during some part of our diver training, that coral reefs are a delicate and complex ecosystem (much like a tropical rainforest) provide habitat for thousands of different species of corals, fish and other marine life. Not only do they provide a home for theses creatures, but in doing so, they attract sharks and turtles, rays and octopus and other cool things to look at!
: 1 - Corals cannot survive for prolonged periods in air. Therefore if trapped air forms pockets, any coral in that pocket will be killed.
: 2 - The physical force of rising, expanding air will pass through delicate branching corals such as acropora (staghorn coral)or sea fans and may break or damage the coral. The area under an overhang is of massive ecological value as it acts as a nursery from juvenile fish. Without these habitats, fish populations may come under threat.
: This type of contact, from bubbles, is an indirect contact.
: The final contact type is the accidental contact. Along with bubble contacts, this is the most destructive. These occur when a fin kicks the coral, a cylinder hits the coral or a body or hand bumps into the coral. These types of contact are common in trainee and newly qualified divers that often have not perfected their buoyancy control and also amongst photographers, who may be desperate to get a good photo but don't notice the coral they are kicking the life out of!
: SGEES
: The University of Birmingham
: B15 2TT
: United Kingdom