FEATURES
CROSSBREEDING ARABIAN GULF CORALS TO ENHANCE CORAL HEAT TOLERANCE Certain reef-building corals from the Arabian Gulf may provide other corals with the gene variants needed to survive rising sea temperatures caused by global climate change.
The Arabian Gulf is the hottest region where reef-building corals live, with coral populations adapted to high temperatures from global climate change that are predicted to hit tropical reefs at the end of this century. This provides scientists with the opportunity to leverage the heat-tolerant gene variants of local reef-building corals to enhance the resilience of other coral populations. Coral reefs are large underwater structures built by colonies of marine invertebrates called coral. Reef-building corals live in symbiosis with microscopic algae, which work together to extract calcium from seawater to create their hard skeletons. Coral reefs play an important role in biodiversity and human life, absorbing wave energy to protect coastlines from erosion, shielding mangrove forests and seagrass beds that serve as fish nurseries, and hosting more than a quarter of all marine fish species, including several culturally and commercially important ones. Corals are also extremely vulnerable to ongoing environmental changes, including rising sea levels, ocean acidification, and most notably, increased water
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temperatures, all of which are triggered by increasing greenhouse gas emissions from human activity. The most destructive and rapid impact on coral reefs from global climate change is the bleaching and dieoffs of corals when sea temperatures are abnormally warm. Coral bleaching occurs when the sea temperature rises by just 1-2°C over the course of a few weeks, causing coral to become stressed and expel the microscopic algae they contain. Those algae live within the coral in a mutually beneficial relationship, enabling each other to survive. If a coral is without its algae inhabitants for a prolonged period of time, it will starve and die. As average sea temperatures have been increasing, so too have coral bleaching events. Between 2014 and 2017, it was estimated that around 75% of tropical coral reefs experienced enough heat-stress to trigger bleaching. With a recent International Panel on Climate Change report warning that global climate may rise beyond 1.5°C in the next decades, enhancing the heat tolerance of corals may assist them to adapt to the increasing temperatures.
