ECOLOGY OF MACROALGAE FROM THE SAND PLAIN CONTIGUOUS TO THE REEF SLOPE OF THE CORALINE SYSTEMS, WITH EMPHASIS IN THE CARIBBEAN SEA

Abstract

The sand plain with cobbles and pebbles formed by the long-term accretion of calcareous red algae around pebbles. shell fragments, or calcareous nodules, contiguous to reef slope of the coraline systems at the Atlantic, are rich in species. Most of these algae are excluded from the reef slope and shallow parts of the reef coral by the herbivorous fish and invertebrates. The most dominant species lack chemical defenses to avoid predation, but evolutionarily, they have developed a competititve ability by the primary space and adaptability to low light levels. Competition for space does not seemed to play an important role in structuring these subtidal communities, but to the cyclic disturbing conditions. generall y a physical factor, which cause a reduction of the most dominant species, thus permitting coexistence with other less dominant species. This condi tion would explain the maintaining of a high species diversity.