Recurrent partial mortality events in winter shape

Authors: Eduard Serrano Marta Ribes Rafel Coma

Publish Date: 2016/10/26

Volume: 36, Issue: 1, Pages: 27-38

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Abstract

Global warming has many biological effects on corals and plays a central role in the regression of tropical coral reefs therefore there is an urgent need to understand how some coral species have adapted to environmental conditions at higher latitudes We examined the effects of temperature and light on the growth of the zooxanthellate coral Oculina patagonica Scleractinia Oculinidae at the northern limit of its distribution in the eastern Iberian Peninsula western Mediterranean by transplanting colonies onto plates and excluding them from space competition over a ~4yr period Each year most of the colonies ~70 exhibited denuded skeletons with isolated polyps persisting on approximately half of the coral surface area These recurrent episodes of partial coral mortality occurred in winter and their severity appeared to be related to colony exposure to cold but not to light Although O patagonica exhibited high resistance to stress coral linear extension did not resume until the coenosarc regenerated The resumption of linear extension was related to the dissociation of the polyps from the coenosarc and the outstanding regenerative capacity of this species 103 mm2 d−1 These biological characteristics allow the species to survive at high latitudes However the recurrent and severe pattern of denuded skeletons greatly affects the dynamics of the species and may constrain population growth at high latitudes in the MediterraneanWe are grateful to Marc Terrades for his assistance in the field the Spanish State Meteorological Agency and the Catalan Water Agency for providing the solar radiation and light attenuation data respectively and the Parc Natural del Montgrí les Illes Medes i el Baix Ter and the Parc Natural de Cap de Creus for their continuous support of our research Financial support was provided by the CSICoral project CGL201343106R of the Spanish Government The authors are part of the Marine Biogeochemistry and Global Change research group of the Generalitat de Catalunya 2014SGR1029

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