Photosynthesis and light utilization in the Caribbean coral Montastraea faveolata recovering from a bleaching event

Abstract

Coral bleaching-the loss of symbiotic dinoflagellates-is initiated when corals are exposed to sea surface temperatures above the regional summer average and has been responsible for massive coral mortality episodes. The ability of symbionts to recolonize the host after bleaching may be critical in determining if a colony will recover or experience mortality. Here, following the serendipitous bleaching of specimens of Montastraea faveolata of known photosynthetic, spectroscopic, and genetic characteristics, we describe changes in photosynthesis and light utilization during the recovery process. Fully recovered M. faveolata had minimum quantum requirements (1/W max ) that are very close to the theoretical minimum, indicating that symbiotic corals are not only one of the most efficient light collectors in nature, but also use this energy with maximum efficiency. Analyses of the photosynthetic responses of M. faveolata throughout the recovery process indicate that during the early stages, the symbiont population exhibited characteristics consistent with acclimation to higher irradiance relative to fully recovered corals. The absorption spectra of bleached samples showed contributions of chlorophyll b (Chl b) associated with a biomass increase of the endolithic algae. The propagation of endolithic algae after bleaching may provide partial protection to the surviving symbionts from excessive radiation by reducing the reflectivity of the skeleton. Changes in the relative abundances of different symbiotic algae between recovered and unbleached colonies did not result in significant variations in photosynthetic and light utilization characteristics.

Coral transcriptome and bacterial community profiles reveal distinct Yellow Band Disease states inOrbicella faveolata

“…The dominant clade A signature in these DD samples could be remnants of lysed cells. Alternatively, certain clade A genotypes have been present during or colonized coral polyps after stress events (Rodríguez-Román et al, 2006;Stat et al, 2008;DeSalvo et al, 2010).…”

Remote Sensing of Coral Bleaching Using Temperature and Light: Progress towards an Operational Algorithm

“…Accumulated photodamage causes a drop in F v /F m . Once the accumulation of damaged PSII induces a dramatic reduction in Symbiodinium population (i.e., coral bleaching), the recovery rate of F v /F m will be dependent on PSII repair of the surviving algae and/or the repopulation of Symbiodinium [47,48].…”

Stable isotopic records of bleaching and endolithic algae blooms in the skeleton of the boulder forming coral Montastraea faveolata

“…Of particular importance is the interaction of the endolith blooming phenomena with coral bleaching or paling (Carilli et al 2010). Endolith growth, photosynthesis, and translocation can increase after bleaching (Fine and Loya 2002;Rodriguez-Roman et al 2006), though it is unclear if the algae provide a sufficient food source to increase the coral's survival after the loss of symbionts. Further work is needed to elucidate the drivers of endolith blooming as well as the potential for these organisms to provide fixed carbon to their host, both during ''normal'' coral growth and times of stress such as bleaching.…”

“…Entire communities of endolithic photoautotrophs (i.e., algae and cyanobacteria) can make up a large proportion of net primary productivity in heads of dead boulder forming corals (Tribollet et al 2006). Yet, when shaded by live coral tissue, endolithic algae receive less than 5% of ambient light (Rodriguez-Roman et al 2006) limiting their productivity to \4% that of coral symbionts (Shashar and Stambler 1992). Despite this, endoliths can translocate fixed carbon to the tissue of their coral host, and both photosynthesis and translocation may be enhanced during endolith blooms (Schlichter et al 1995;Fine and Loya 2002).…”