How does climate change threaten coral reefs and fisheries in Tuvalu?

Climate change poses a severe existential threat to the coral reefs and fisheries of Tuvalu through two primary, interconnected processes: rising seawater temperatures and ocean acidification.12

Impact on Coral Reefs

• Coral Bleaching: Elevated seawater temperatures cause corals to expel their symbiotic algae, known as zooxanthellae, which provide them with essential nutrients and color. If these algae do not return, the coral may die, leading to the collapse of the reef structure.13
• Ocean Acidification: As the oceans absorb increased levels of carbon dioxide, the water becomes more acidic. This reduces the availability of carbonate ions, making it difficult for corals to build and maintain their calcium carbonate skeletons.2

Impact on Fisheries

• Habitat Loss: Because coral reefs serve as the foundation for marine ecosystems, their degradation results in a loss of habitat and food sources for numerous species. This can cause populations of reef-dependent fish to drop precipitously.1
• Physiological Stress: Increasing acidity can cause acidosis in fish, negatively affecting their growth, reproduction, and respiration. Furthermore, the decline of smaller organisms at the base of the food chain forces predator populations to shift or decline, threatening the stability of the entire marine food web.2