blog writing #coral bleaching determinants and the symbiotic relationship between zooxanthellae and corals

Coral bleaching refers to the biological process that occurs as a result of corals getting stressed by changes in conditions such as temperatures, light, or nutrients, which causes the expelling of algae living in their tissues that makes them turn completely white. Additionally, experiments and observations show that coral bleaching occurs as a result of elevated seawater temperature under high light conditions, which leads to increased rates of biochemical reactions associated with zooxanthellae photosynthesis, producing toxic forms of oxygen that disrupt cellular processes (Coles & Brown, 2003). Corals are a type of calcareous rock, which is primarily made off the skeletons of minute sea organisms called ‘polyps. Accumulation of the skeletons of these lime-secreting organisms is what results in the formation of coral reefs and atolls. Classification of coral reefs is done based on the nature of its shape and mode of occurrence in three categories. The fringing reef is a kind of coral reef that develops along the continental margins or along with the islands. Barrier Reef is the largest, most extensive, highest, and widest reef among all kinds of coral reefs. This type of coral reef is formed off the coastal platforms and parallel to them. Atoll reef is a ring of a narrow growing chorus of horseshoe shape and crowned with palm trees. This type of coral reef is found around an island or in an elliptical form on a submarine platform (Anwar, 2017). Zooxanthellae are plant-like organisms that live in the tissues of many animals such as some corals, anemones, and jellyfish, sponges, flatworms, mollusks, and foraminifera. Such microscopic algae capture light from the sun and convert it into energy just like in plants, in order to provide essential nutrients to the corals. They are species members of the phylum Dinoflagellata. They usually form a symbiotic relationship with other marine organisms, especially the coral (LaJeunesse, 2020).