Pigmentation changes in Siderastrea spp. during bleaching events in the costal reefs of northeastern Brazil

Abstract

ABSTRACT. We report here the occurrence of seasonal changes in the pigmentation of colonies of Siderastrea spp. during bleaching events on coastal reefs in northeastern Brazil. Bleached affected almost 50% of coral colonies analyzed in Cabo Branco reefs (Paraiba state) in the summer of 2005. The same phenomenon was detected along various coastal reefs in northeastern Brazil during the summer of 2007 and 2008. These events were seasonal, and began with the emergence of pale colonies that became pale-pink and then purple during the rainy months. The patterns and intensity of colonies pigmentation changes varied with the studied sites. The decrease in zooxanthellae density and chlorophyll-a content was quantified in the colonies with their pigmentation pattern altered (bleaching). Microbiological analyses revealed higher densities of bacteria in pink colonies (bleached) as compared to brown colonies (normal). Environmental disturbances may lead to the pigmentation changes in Siderastrea spp., but the immediate causes of this phenomenon are not clear and require further investigations. Keywords: zooxanthellae, bacteria, marine ecology, pink colonies, Brazilian reefs.Cambios en la pigmentación de colonias de Siderastrea spp. durante los eventos de blanqueamiento en arrecifes costeros del noreste de Brasil RESUMEN. Se relata aquí la aparición de cambios estacionales en la pigmentación de colonias de Siderastrea spp. durante los eventos de blanqueamiento en arrecifes costeros del noreste de Brasil. En verano de 2005, existían casi 50% de colonias blanqueadas en los corales analizados en Cabo Branco, Estado de Paraíba. El mismo fenómeno se detectó a lo largo de varios arrecifes costeros en el noreste del país durante el verano de 2007 y 2008. Estos eventos son asociados a la variación estacional, que comenzaron con la aparición de colonias pálidas que luego se convirtieron en rosa pálido y después a morado, durante los meses de lluvias. Los patrones e intensidad de los cambios en la pigmentación de las colonias fueron diferentes en los sitios estudiados. La disminución de la densidad de zooxantelas y del contenido de clorofila-a fue cuantificada en las colonias y comparados con el patrón de pigmentación alterada (blanqueo). Los análisis microbiológicos revelaron densidades más altas de bacterias en colonias rosas (blanqueada) en comparación con las colonias marrones (considerados normales). Las alteraciones ambientales pueden conducir a estos cambios de pigmentación en Siderastrea spp., pero las causas inmediatas de este fenómeno no están claras y requieren más investigación. Palabras clave: zooxantelas, bacterias, ecología marina, colonias rosas, arrecifes brasileños.

Stony Coral Tissue Loss Disease in Florida Is Associated With Disruption of Host–Zooxanthellae Physiology

“…In Siderastrea spp. showing marked variability in pink pigmentation associated with bleaching, Sassi et al (2015) reported that pocilloporin fluorescent pigments became visible in the deeper tissue layers with reduced zooxanthellae densities (as described by Bongiorni and Rinkevich, 2005). Perhaps similar mechanisms exist for S. siderea with SCTLD.…”

A widespread necrotizing disease affecting Palythoa caribaeorum (Duchassaing and Michelotti, 1860) on coastal reefs in northeastern Brazil

“…It is also possible that this disease is caused by a set of opportunist microorganisms that proliferate when environmental conditions are unfavorable, and the colonies become weakened. Sassi et al (2015) demonstrated that pink colonies of Siderastrea stellata have significantly higher densities of viable bacteria in the tissue than the healthy colonies.…”

“…Diseases affecting reef organisms are becoming more prevalent and of more significant concern globally (Porte et al, 2011;Séré et al, 2016;Richardson, 1998;Palmer et al, 2011aPalmer et al, , 2011bTraylor-Knowles et al, 2017). Symbiotic relationships are thrown into disarray when those diseases appear, and synchronicities are interrupted -alterations that can result in the death of those organisms and/or favor the development of other life forms (Gantar et al, 2011;Sudek et al, 2012;Sassi et al, 2015).…”

“…Disequilibria such as these have been documented globally for more than 30 years, but these phenomena have not yet been well studied in Brazil. Diseases involving corals and zoantharians have been documented (Acosta, 2001;Francini-Filho et al, 2008), but no detailed studies have been performed on Brazilian reefs, although cases of local bleaching (without excessively severe consequences for coral populations) have been reported (Migotto, 1997;Costa et al, 2001;Soares and Rabelo, 2014;Sassi et al, 2015;Banha et al, 2019). The necrotizing disease that affects specimens of Palythoa caribaeorum on Brazilian coastal reefs has attracted recent attention, however, because of its aggressiveness -drastically reducing colony sizes within just a few weeks.…”

Experimental effects of multiple thermal stress events on chlorophyll-a content and size of <i>Cassiopea andromeda</i> and the role of heterotrophic feeding and <i>Symbiodinium</i> concentration

“…The majority of the papers attributed the bleaching to temperature anomalies, varying between 0.25 and 3.2 above the average. Ultraviolet radiation, sedimentation, low salinity and anthropic activities were also considered impacts (Barradas et al, 2010;Soares and Rabelo, 2014;Sassi et al, 2015).…”