Project description:As reef-building corals are increasingly being exposed to persistent threats that operate on both regional and global scales there is a pressing need to better understand the complex processes that diminish coral populations. This study investigated the impacts of the Florida Red Tide dinoflagellate Karenia brevis and associated brevetoxins on selected facets of coral biology using Porites astreoides as a model system. When provided with choice assays, P. astreoides larvae were shown to actively avoid seawater containing red tide or purified brevetoxins. However, forced exposure to similar treatments induced time-dependent physiological and behavioral changes that were captured by PAM fluorometry and settlement and survival assays, respectively. Adult fragments of P. astreoides exposed to red tide or associated brevetoxins displayed signs of proteomic alterations that were characterized by use of an iTRAQ-based quantitative proteomic analysis. The novel use of this technique on P. astreoides demonstrated that protein expression was highly contingent upon biological versus chemical treatment and that several broad pathways associated with cell stress were affected including redox homeostasis, protein folding, energy metabolism, and reactive oxygen species (ROS) production. The results herein provide new insight into the ecology, behavior and sublethal stress of reef-building corals in response to K. brevis exposure and underscore the importance of recognizing the potential of red tide to act as a regional stressor to these important foundation species.
