The upper seaward slopes are usually the most productive parts of the system, with most of the basic food production and deposition of the limestone skeleton taking place here. Bytheway, as an interesting little side note, red reef fish are camouflage at night. Mangrove's role in reef preservation Corals are acutely sensitive to changes in their environment. Mangrove destruction for charcoal or building material adds sediment to the waters. Coral is extremely sensitive to sediment.
Mangrove forests collect the sediments in the water.
Scientists are just now beginning to realize how the mangroves do this. The mangled roots of the trees create areas of water turbulence. The sediment comes in on the rising tide and the sediment is trapped. In other words, the sediment comes in with the tide, is trapped in the root systems, but the ebbing tide is not capable of taking all of the sediment back out to sea. Thus the mangrove forest is an important part of the coral reef by ways of sediment entrapment.