Korallblekning

Korallblekning, also known as coral bleaching, is a phenomenon where corals expel the algae living in their tissues, causing the coral to turn completely white. This process is a stress response to changes in conditions such as temperature, light, or nutrients. The algae, known as zooxanthellae, provide corals with most of their energy through photosynthesis, and their loss can lead to coral death if the stress persists.

Coral bleaching is primarily caused by increased sea surface temperatures, often associated with climate change. When water temperatures rise, corals become stressed and expel the zooxanthellae. If the stress continues, the corals can die, leading to the loss of entire reef ecosystems. Bleaching events can be categorized as mild, moderate, or severe, depending on the extent of coral loss.

The Great Barrier Reef in Australia has experienced several severe bleaching events, with the most recent in 2016 and 2017, which caused widespread coral death. Bleaching can also be triggered by other factors such as pollution, disease, or changes in ocean chemistry due to increased carbon dioxide levels.

Efforts to mitigate coral bleaching include reducing greenhouse gas emissions to lower sea temperatures, protecting coral reefs from pollution, and promoting coral resilience through conservation and restoration efforts. Understanding and addressing the causes of coral bleaching is crucial for the preservation of these vital ecosystems and the biodiversity they support.