8.5 Friday, Jan. 4 Physiological and genetic underpinnings of local coral adaptation in the Florida Keys KENKEL, CD*; ALMANZA, AT; MATZ, MV; Univ. of Texas at Austin; Univ. of Texas at Austin; Univ. of Texas at Austin firstname.lastname@example.org
Coral reefs throughout the world, and especially in the Caribbean, are experiencing declines attributable to direct anthropogenic impacts on reef ecosystems exacerbated by the effects of global climate change. However, the relationships between environmental parameters and coral reef health are far from clear. In the Florida Keys, offshore reefs experience seemingly benign environmental conditions yet exhibit consistently lower coral cover and lower coral growth rates than mid-channel and inshore patch reefs that are subject to higher nutrient loads and thermal extremes. We preformed reciprocal transplants of the mustard hill coral, Porites astreoides, between two inshore and two offshore reefs to identify patterns of local adaptation and the physiological and/or genetic mechanisms that enable this species to inhabit both reef environments. Each of the four locations was represented by 15 genotypes (individual colonies), which were fragmented and outplanted at local and foreign sites. Samples of each individual were collected after six months and one year. Microsatellite analysis of the coral host revealed subtle but significant genetic subdivision between inshore and offshore populations, potentially facilitating local adaptation. Following the first six months of transplantation, offshore-origin corals exhibited higher growth rates and higher protein content than inshore corals at all sites. In addition, all coral genotypes tended to grow less at offshore sites compared to inshore, suggesting the presence of some unidentified stressor(s) that might explain lower coral cover at offshore reefs. Ongoing analysis of additional metabolic parameters in both the host and symbiont together with host global gene expression profiling with RNAseq will provide further insight into physiological and molecular mechanisms underlying these patterns.