By touching the coral this can remove mucus which may leave it open to disease, bacteria or algae. Touching can also cause actual breakage of the reef. Sedimentation Divers stir up sediment if they swim too close to the reef or sandy areas between and also if they make contact with the bottom. This can affect a reef in a number of different ways Physical interfers with coral nutrition by coating feeding surfaces responsible for catching prey items, this can exact a high energetic cost as coral uses mucus secretion and ciliary action to shed sediments. It also interfers with the recruitment of coral larvae, as this requires a solid surface upon which to settle and metamorphose.
Sediment can also abrade the corals.
Biologically causes a reduction in available quantity and quality of light which effects coral nutrition, growth, reproduction and depth distribution as photosynthetic output of zooxanthellae is decreased. It increases awareness about the environment we live in, opening up a new world. Diving is not a cheap hobby and diver expenditure is great bringing in money for the surrounding communities through dive rental and charters, accomodation, food, gifts, services and sales tax. It creates employment for many people such as those at dive stores and charter shops, and also those involved with the provision of services such as those in the hotels, restuarants and aslo the entertainment industry. Another important advantage of recreational divers is that they are an untapped resource.