Resumen de Periodic endolithic algal blooms in Montastraea faveolata corals may represent periods of low-level stress
Jessica E. Carilli, Jessie Godfrey, Richard D. Norris, Stuart A. Sandin, Jennifer E. Smith
Cores from the scleractinian coral Montastraea faveolata (Ellis and Solander, 1786) sensu weil and Knowlton (1994) from the Mesoamerican Reef possess obvious green bands, sometimes occurring annually, but more often at less frequent intervals. Bands are remnant concentrations of the endolithic green alga Ostreobium spp. that grow parallel to and below the living coral tissue. We dated green bands in 58 M. faveolata cores collected from four sites on the Mesoamerican Reef. We found that the bands are not related to coral skeletal growth reductions, but instead are caused by algal blooms within the coral skeleton. We hypothesize that the blooms occur during periods of coral paling (the partial loss of pigmentation), during which more light penetrates through the translucent coral tissue into the coral skeleton. This hypothesis is supported by observations of discontinuous banding within the skeleton, the patchiness of pigment loss in living corals, and ecological observations of endolithic algal blooms in living bleached corals. At three sites, there was a significant increase in green band occurrence over time, which suggests that coral paling may have increased over the last several decades.
