image: A coral nursery panel after the 2015 bleaching event. Nursery colonies from warm adapted parents are outlined in red. Colonies from heat sensitive parents are outlined in blue. After 8 months of growing alongside each other, nursery colonies grown from heat resistant parents show 2-3 times less bleaching than colonies grown from heat sensitive parents. Four species are growing here: Porites cylindrica, Pocillopora damicornis, Acropora hyacinthus and Acropora gemmifer (from upper left, clockwise). view more
Credit: Image courtesy of Megan K. Morikawa.
A study examines the ability of naturally heat-tolerant coral species to maintain heat tolerance in different environments, such as nurseries used in coral restoration efforts. Coral reefs worldwide face widespread bleaching due to rising ocean temperatures. Some coral species include individual colonies thriving in high-heat environments, and such colonies have been proposed as potential nursery stock for coral restoration efforts. However, the heat-tolerance could stem from adjustable physiology, microbiome-related effects, or symbiont-related effects. To test whether colonies are likely to retain heat-tolerance when transferred to nurseries, Megan K. Morikawa and Stephen R. Palumbi placed 800 fragments from 80 colonies with varying heat tolerance from four coral species in nurseries at Sili Reef in American Samoa in the South Pacific Ocean in the winter of 2014. After the 2015 global bleaching event in the Samoan archipelago, nursery colonies from heat-tolerant parent corals showed two-fold to three-fold less bleaching, compared with corals from less heat-tolerant parent species, even after 8 months of acclimatization in a common garden. These colonies also retained relatively higher genetic diversity. Additionally, the authors found a correlation between the bleaching of nubbins, which are biological replicates of parent colonies, with the parent colony's pool of origin and symbiont genus. According to the authors, selecting coral colonies that can withstand warm ocean conditions could aid the development of nurseries for climate-resilient corals.
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Article #17-21415: "Using naturally occurring climate resilient corals to construct bleaching-resistant nurseries," by Megan K. Morikawa and Stephen R. Palumbi.
MEDIA CONTACT: Stephen R. Palumbi, Stanford University, Pacific Grove, CA; tel: 831-655-6214; e-mail: <spalumbi@stanford.edu>
Journal
Proceedings of the National Academy of Sciences