Project: RAPID: surviving climate change - the role of acclimatization in reef-building corals

Description from NSF award abstract:
August of 2014 was the warmest on record for the Florida Keys reef tract and by early September numerous corals species were severely stressed and looked bleached. This ongoing large-scale bleaching event provides an unprecedented opportunity to understand if prior stress exposure hardens individual coral colonies to future hot water events -- a process called acclimatization. This study combines long-term monitoring data of individual coral colonies with a stress experiment in the summer of 2015 to determine whether partially bleached colonies have acclimatized, to what extent, and by what means. The answers may fundamentally shape our understanding of how reefs might survive climate change. This is important because tropical coral reefs harbor more species then tropical rainforests and generate billions of dollars each year for local and national economies. The focal species of this project is the endangered elkhorn coral, Acropora palmata and results of the work can be used directly by managers when choosing coral colonies for conservation. The project will educate and train the public and public institutions on numerous levels. The scientists have partnered with the Coral Restoration Foundation, a non-for profit organization that delivers scientific knowledge and hands on experience in coral restoration to over 300 high school students per year. Postdoctoral scholars, and students are an integral part of this project and will receive training in field and laboratory work and lecture courses.

Acclimatization is a non-genetic process by which an individual heightens its tolerance after exposure to a stressor, such as temperature anomalies. Recent work has shown that acclimatization may be an important process by which corals may survive climate change. However, because reef-building corals harbor endosymbiotic Symbiodinium, discerning the relative contribution of host and symbiont to acclimatization can be difficult. The endangered Caribbean elkhorn coral, Acropora palmata, has an uncomplicated symbiosis: it associates with just one symbiont species (Symbiodinium fitti) and most colonies also harbor only one strain of S. fitti over space and time. August of 2014 was the warmest on record for the Florida Keys reef tract and by early September numerous corals species were severely stressed and looked bleached. This event provides an unprecedented opportunity to understand the role of acclimatization in reef corals. Initial surveys of A. palmata documented a range of bleaching response. This response varied between reefs but also within single, monoclonal stands of A. palmata. Thus, coral clone mates were observed to exhibit different bleaching susceptibilities despite indications that they share identical (clonal) symbiont communities, begging the question as to what mechanisms account for such differences. The answers may fundamentally shape our understanding of how reefs might survive climate change. Immediate support is requested to sample coral colonies while they are still bleached and for which long term performance histories exist. Results from this initial assessment are essential to inform the centerpiece of the proposal: a stress experiment to determine whether partially bleached colonies have acclimatized, to what extent, and by what means.

This is an NSF Collaborative Research project.