controls on coral-ground development along the northern mesoamerican reef tract控制沿着中美洲北部礁珊瑚地发展.pdfVIP

Controls on Coral-Ground Development along the Northern Mesoamerican Reef Tract ´ ´ 1 ´ ´ 1 2 1 Rosa E. Rodrıguez-Martınez , Adan G. Jordan-Garza , Miguel A. Maldonado , Paul Blanchon * ´ ´ ´ ´ ´ 1 Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnologıa, Universidad Nacional Autonoma de Mexico, Cancun, Quintana Roo, Mexico, 2 Centro ´ ´ Ecologico Akumal A.C. Akumal, Quintana Roo, Mexico Abstract Coral-grounds are reef communities that colonize rocky substratum but do not form framework or three-dimensional reef structures. To investigate why, we used video transects and underwater photography to determine the composition, structure and status of a coral-ground community located on the edge of a rocky terrace in front of a tourist park, Xcaret, in the northern Mesoamerican Reef tract, Mexico. The community has a relatively low coral, gorgonian and sponge cover (,10%) and high algal cover (.40%). We recorded 23 species of Scleractinia, 14 species of Gorgonacea and 30 species of Porifera. The coral community is diverse but lacks large coral colonies, being dominated instead by small, sediment-tolerant, and brooding species. In these small colonies, the abundance of potentially lethal interactions and partial mortality is high but decreases when colonies are larger than 40 cm. Such characteristics are consistent with an environment control whereby storm waves periodically remove larger colonies and elevate sediment flux. The community only survives these storm conditions