Effects of ocean acidification on the potency of macroalgal allelopathy to a common coral.

Many coral reefs have phase shifted from coral to macroalgal dominance. Ocean acidification (OA) due to elevated CO is hypothesised to advantage macroalgae over corals, contributing to these shifts, but the mechanisms affecting coral-macroalgal interactions under OA are unknown. Here, we show that (i) three common macroalgae are more damaging to a common coral when they compete under CO concentrations predicted to occur in 2050 and 2100 than under present-day conditions, (ii) that two macroalgae damage corals via allelopathy, and (iii) that one macroalga is allelopathic under conditions of elevated CO, but not at ambient levels.

Massive bleaching of coral reefs induced by the 2010 ENSO, Puerto Cabello, Venezuela.

El Niño Southern Oscillation (ENSO) has generated global coral massive bleaching. The aim of this work was to evaluate the massive bleaching of coral reefs in Puerto Cabello, Venezuela derived from ENSO 2010. We evaluated the bleaching of reefs at five localities both at three and five meter depth.

[Temporary abundance variation of Coralliophila abbreviata and Coralliophila caribaea (Mollusca, Coralliophilidae) in a coral reef at Morrocoy National Park].

The mollusks Coralliophila abbreviata and C. caribaea are coral predators in the Caribbean Sea . We evaluated the temporal variability of abundance and size structure of C.

[Abundance of Diadema antillarum (Echinodermata: Echinoidea) in the coasts of Venezuela].

Diadema antillarum is a shallow-water sea-urchin from the tropical Atlantic whose populations almost disappeared in 1983-84 because of widespread mortalities which reached 87-100 %. In Venezuela, urchin population densities before the mortality event were comparable to those of other Caribbean regions; however, later abundancies remain unknown. The objectives of this study were to evaluate the recent densities of certain D.