1 3 Mar Biol (2014) 161:131–139 DOI 10.1007/s00227-013-2322-5 ORIGINAL PAPER The effects of an abnormal decrease in temperature on the Eastern Pacific reef-building coral Pocillopora verrucosa A. P. Rodríguez-Troncoso · E. Carpizo-Ituarte · D. T. Pettay · M. E. Warner · A. L. Cupul-Magaña Received: 25 June 2013 / Accepted: 30 August 2013 / Published online: 12 September 2013 © Springer-Verlag Berlin Heidelberg 2013 opposed to translocation to the host coral. With a decreased availability of symbiont-derived carbon, the coral likely catabolized storage lipids in order to survive the stress event. Despite this stress and some tissue necrosis, no mortality was noted and corals recovered quickly when returned to the ambient temperature. As these results are in marked contrast to similar studies investigating elevated temperature on this coral from this same location, Pocil- lopora in the Mexican Central Pacific may be more prone to long-term damage and mortality during periods of ocean warming as opposed to ocean cooling. Introduction In recent years, global coral communities have been increasingly affected by bleaching, whereby the dinoflag- ellate (genus Symbiodinium) that forms an endosymbiosis with reef corals is expelled from the host. The majority of bleaching events from the past several decades have been associated with abnormal increases in sea surface tempera- ture, at times occurring during El Niño events (Kleypas et al. 2001; Hoegh-Guldberg et al. 2007). With the future predictions of more frequent and severe bleaching events linked with global climate change (Veron et al. 2009), there is concern that the capacity for survival of coral communi- ties may become compromised. Coral communities from the Mexican Pacific (MP) are composed by fringing reefs, where corals in the genus Pocillopora are ecologically dominant and are distrib- uted in the shallower areas, though members of the genera Pavona and Porites are found in deeper areas (Carriquiry et al. 2001). Reefs of the central MP, which are character- ized by higher species richness (Reyes-Bonilla and López- Pérez 1998), have suffered massive bleaching events due Abstract Coral bleaching events are associated with abnormal increases in temperature, such as those produced during El Niño. Recently, a breakdown in the coral–dino- flagellate (genus Symbiodinium) endosymbiosis has been documented in corals exposed to anomalously cold-water temperatures associated with La Niña events. Given the ecological significance of such events, as well as the threat of global climate change, surprisingly little is known about the physiological response of corals to cold stress. This study evaluated some physiological effects of continuous temperature decline in colonies of the eastern Pacific reef- building coral Pocillopora verrucosa. Twenty days of incu- bation at 18.5–19.0 °C resulted in a substantial decrease in holobiont lipid and Chla content, as well as an increase in Symbiodinium density. These observations suggest a com- bination of symbiont acclimation due to the temperature decline and reallocation of carbon toward algal growth as Communicated by U. Sommer. Electronic supplementary material The online version of this article (doi:10.1007/s00227-013-2322-5) contains supplementary material, which is available to authorized users. A. P. Rodríguez-Troncoso · A. L. Cupul-Magaña (*) Departamento de Ciencias Biológicas, Centro Universitario de la Costa, Universidad de Guadalajara, Av. Universidad No. 203, 48280 Puerto Vallarta, Jalisco, Mexico e-mail: amilcar_cupul@yahoo.com.mx E. Carpizo-Ituarte Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Carretera Ensenada-Tijuana Km 103, 22860 Ensenada, Baja California, Mexico D. T. Pettay · M. E. Warner College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA