NCAR Imperative 1 | Coral Reef Bleaching

Many corals worldwide are currently being impacted by what has been labeled the third global coral bleaching event.  Large-scale bleaching events occur when corals experience thermal stress that arises from a combination of global warming and ENSO conditions.  The current global-scale bleaching event began in the summer of 2014, and is predicted to last well into 2017, making it the longest bleaching event on record, and making it likely that some reefs will re-experience bleaching conditions before the corals can recover.  In conjunction with colleagues at the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), CGD’s leading expert in coral reef flew to Costa Rica to work on coral reefs in the Golfo Dulce, an embayment on Costa Rica’s Pacific coast.  Coral reef ecosystems in the Golfo Dulce were decimated in the 1950s by sedimentation resulting from deforestation of the surrounding rainforests.   Conditions have improved since then, and the coral ecosystems have been recovering.  The CGD project cultured corals in underwater nurseries using different methodologies, and investigated how recovery varies amongst different coral genotypes. Unfortunately, the work is further challenged by the fact that the Golfo Dulce corals are currently experiencing coral bleaching.  On the one hand, this can decimate coral populations, but on the other hand, it reveals which corals are better adapted to elevated temperatures, and should thus be selected for propagation.

Bleached and stressed coral on the Great Barrier Reef
Bleached and stressed coral on the Great Barrier Reef. Credits: NASA/JPL-Caltech/BIOS