CORAL BLEACHING Meaning and
Definition
-
Coral bleaching refers to a phenomenon in which coral colonies lose their vibrant and diverse colors, turning completely or partially white. It occurs when stressors, such as increasing sea temperatures, pollution, or changes in water chemistry, cause corals to expel the symbiotic algae called zooxanthellae that live within their tissues. These algae provide corals with essential nutrients through photosynthesis and contribute to their bright hues. However, when corals are exposed to prolonged stress or unfavorable conditions, they expel the algae, leading to the loss of vibrant pigmentation.
The expulsion of zooxanthellae leaves corals weakened, susceptible to diseases, and ultimately facing the risk of death. The absence of these tiny algae also increases the transparency of corals, making their limestone skeleton more visible, giving them a bleached appearance. This is why the term "coral bleaching" is used.
Coral bleaching is a significant concern for marine ecosystems as corals provide essential habitat and support for numerous species. The loss of vibrant colors indicates that corals are undergoing severe stress and are more vulnerable to other threats, including physical damage and disease outbreaks.
The occurrence and severity of coral bleaching events have increased in recent decades due to human-induced climate change and other stressors. Monitoring and understanding coral bleaching events are crucial for devising effective conservation strategies to mitigate their impacts and protect these vital and diverse ecosystems.
Etymology of CORAL BLEACHING
The word "coral" originates from the Old French "corail" or medieval Latin "corallium", which ultimately is derived from the Greek word "korallion". The term "bleaching" is derived from the verb "bleach", which can be traced back to the Old Norse word "bleikja" meaning "to make white". Thus, "coral bleaching" describes the process of corals losing their color and turning white due to environmental stressors.
