COMPOSICIÓN Y ESTRUCTURA DE LA COMUNIDAD DE OCTOCORALES EN LOS BAJOS DE SANCHO PARDO, ARRECIFE DE LOS COLORADOS, CUBA

Se estudiaron la composición y estructura de las comunidades de octocorales en cinco sitios localizados en los Bajos de Sancho Pardo (arrecife de Los Colorados (NW Cuba) en agosto del 2010. Se empleó como unidad de muestreo un marco cuadrado de un metro de lado. En total se estudiaron 11 zonas del arrecife frontal, dos zonas traseras y una cresta. Se identificaron 34 especies de gorgonias de 2687 colonias. En el arrecife frontal, Pseudopterogorgia americana y Pseudopterogorgia elisabethae fueron las especies dominantes, mientras que en la zona trasera lo hicieron Briareum asbestinum y Pseudopterogorgia bipinnata. En la cresta arrecifal predominaron Gorgonia ventalina y Plexaura homomalla. Se encontraron diferencias significativas (P = 0.05) para la densidad de gorgonias entre localidades del arrecife frontal. Los resultados de los índices de heterogeneidad y de equitatividad permiten inferir que un 79% de las localidades se correspondieron con ambientes favorables o muy favorables y el 64% indicaron ambientes constantes o casi constantes. En el 79% de las localidades se infirió una tensión hidrodinámica baja y en el resto resultó entre moderada y alta en zonas someras de la cresta y el arrecife frontal. El estado general de la comunidad de octocorales fue bueno según los valores de densidad y abundancia de especies registrados, aunque se evidencia que en las zonas al oeste hay un mayor cubrimiento por macroalgas carnosas, que puede constituir un factor que limita el reclutamiento. ABSTRACTThe composition and structure of octocoral communities was studied in five locations in Bajos de Sancho Pardo (Los Colorados reefs (NW Cuba)) in August 2010. Quadrants measuring one square meter were used as sampling units. A total of 11 fore reefs, two rear zones and one reef crest were studied. Thirty-four species of gorgonians were identified in 2687 colonies. Predominant species included Pseudopterogorgia americana and Pseudopterogorgia elisabethae in the fore reef zone, Briareum asbestinum and Pseudopterogorgia bipinnata in the rear reef, and Gorgonia ventalina and Plexaura homomalla in the reef crest. Significant differences (P = 0.05) were found in the density of gorgonians between fore reef stations. Based on the results of the heterogeneity and evenness indexes, it can be inferred that 79% of the stations were consistent with favorable or very favorable environments and 64% with constant or nearly constant environments. Hydrodynamic stress was low in 79% of the stations, while it was moderate to high in shallow areas of the crest and fore reef. The overall condition of the octocoral community was good according to recorded values of species density and abundance, although it is evident that in the western areas there is greater coverage by fleshy macroalgae, which may be a limiting factor for growth.

Antifouling Activities against Colonizer Marine Bacteria of Extracts from Marine Invertebrates Collected in the Colombian Caribbean Sea and on the Brazilian Coast (Santa Catarina)

The growth inhibition of 12 native marine bacteria isolated from Aplysina sponge surfaces, the shell of a bivalve, and Phytagel™ immersed for 48 h in sea water were used as indicator of the antifouling activity of the extracts of 39 marine organisms (octocorals, sponges, algae, and zoanthid) collected in the Colombian Caribbean Sea and on the Brazilian coast (Santa Catarina). Gram-negative bacteria represented 75% of the isolates; identified strains belonged to Oceanobacillus iheyensis, Ochrobactrum pseudogrignonense, Vibrio campbellii, Vibrio harveyi, and Bacillus megaterium species and seven strains were classified at genus level by the 16S rRNA sequencing method. The extracts of the octocorals Pseudopterogorgia elisabethae, four Eunicea octocorals, and the sponges Topsentia ophiraphidites, Agelas citrina, Neopetrosia carbonaria, Monanchora arbuscula, Cliona tenuis, Iotrochota imminuta, and Ptilocaulis walpersii were the most active, thus suggesting those species as antifoulant producers. This is the first study of natural antifoulants from marine organisms collected on the Colombian and Brazilian coasts.