Conservation genetics and the resilience of reef‐building corals

Abstract

Coral reefs have suffered long-term decline due to a range of anthropogenic disturbances and are now also under threat from climate change. For appropriate management of these vulnerable and valuable ecosystems it is important to understand the factors and processes that determine their resilience and that of the organisms inhabiting them, as well as those that have led to existing patterns of coral reef biodiversity. The scleractinian (stony) corals deposit the structural framework that supports and promotes the maintenance of biological diversity and complexity of coral reefs, and as such, are major components of these ecosystems. The success of reef-building corals is related to their obligate symbiotic association with dinoflagellates of the genus Symbiodinium. These one-celled algal symbionts (zooxanthellae) live in the endodermal tissues of their coral host, provide most of the host's energy budget and promote rapid calcification. Furthermore, zooxanthellae are the main primary producers on coral reefs due to the oligotrophic nature of the surrounding waters. In this review paper, we summarize and critically evaluate studies that have employed genetics and/or molecular biology in examining questions relating to the evolution and ecology of reef-building corals and their algal endosymbionts, and that bear relevance to coral reef conservation. We discuss how these studies can focus future efforts, and examine how these approaches enhance our understanding of the resilience of reef-building corals.

Bioindicators of changes in water quality on coral reefs: review and recommendations for monitoring programmes

“…Genetic biomarkers are emerging as powerful tools to identify sources of stress and measure stress responses in corals Morgan et al 2005) and their symbionts (Leggat et al 2007 and see reviews by van Oppen and Gates 2006;Foret et al 2007). Regulation of stress-specific genes is determined by comparing gene expression in populations exposed to environmental stressors with those at reference conditions.…”

Diversity of cutaneous bacteria with antifungal activity isolated from female four-toed salamanders

“…Bacteria are increasingly viewed as mutualists that are often essential for the survival of their host (McFall Ngai et al, 2005). Symbioses of microorganisms with invertebrate and vertebrate species have been studied in regard to diversity of microbial symbionts, host specificity of these symbionts, and details about beneficial effects of these symbioses have been elucidated (for example, Currie, 2001;Douglas, 2003;Nyholm and McFall-Ngai, 2004;van Oppen and Gates, 2006). Living in moist or aquatic environments, amphibians are exposed to microorganisms through contact with soil, water, plants and each other.…”

Coral Reef Resilience through Biodiversity

“…We need to have a better understanding of the molecular and physiological mechanisms that determine the tolerance of coral hosts and zooxanthellae to different stressors [99,177]. Although some corals may be able to adapt to higher seawater temperatures (see [178,179]), we do not know how much or how quickly.…”

“…Sammarco and Strychar [209] point out our lack of understanding of how corals and their symbionts respond to stressors other than increasing seawater temperatures. Van Oppen and Gates [99] note that hybridization of coral species, while evidently rare, could, over evolutionary time scales, make corals more capable of responding to environmental changes "providing the potential for adaptive evolution. "…”

“…Coral diseases are complex, involving corals, the environment, and associated microbial communities [96][97][98]. New research approaches using genetics and molecular biology could help demonstrate the shis in the microbiota that occur when a coral becomes diseased and help reveal how the coral holobiont responds to particular stresses [99,100].…”