Coral reefs resort to colorful measures to save themselves and get back their partners. Glowing coral reefs are not merely a sign of display. The sparkling color arrangement of vibrant blue, pink, yellows, purples, and reds, are attempts by the corals to recover the algae that are vital to their survival.
A study in Current Biology, a journal has revealed that corals have an interdependent relationship with algae which is quite extraordinary. The algae live within the tissue of the organism. When their relationship is flourishing, the corals display a healthy brown tinge.
It was found that periods of stress do not always turn the corals white. Critical nutrient conditions or exposure to brief periods of heat can result in the loss of vital symbiotic algae. But it also triggers a visual feedback loop that produces a display of dazzling and glowing coral reefs with myriad colors. The corals recover as a result of this period of enhanced pigmentation.
The brown symbiotic algae reside inside the tissue of the corals and deliver vital nutrients. However, the algae become toxic to the host corals as a result of the rise in water temperatures or an unfavorable nutrient environment. The corals then reject them and subsequently starve resulting in their death.
Glowing Coral Reefs Is A Common Occurrence
But there are numerous instances when the bleaching process does not result in white corals. The bleaching in 2016 in New Caledonia produced brilliant hues of yellow, pink, and blue. There was little information on what caused such a glowing coral reef.
Later studies revealed that this colorful display of glowing coral reefs is a common occurrence in corals. The colors are derived from a group of protein pigments that the coral host produces. There are fluorescent pigments too, that impart the striking neon glow.
Further research revealed that the pigments shield the mutual relations and save the algae from extra amounts of sunlight by shielding the tissues where the algae usually are found. As the corals detect excess sunlight they begin producing excess sunscreen pigments within the blue range of the spectrum, especially its blue range. This helped us realize the reason for the bright colors that at times appear during the bleaching process.
It was apparent to scientists that the species enveloped themselves in bright and florescent light to get the algae back. It was their way to create the right condition for the return of the light-sensitive algae.
Prof. Jorg Wiedenmann of the department of Biological Oceanography at the University of Southampton said that these colorful pigments produce a sunscreen of their own regularly, The glowing coral reef is a technique for their survival.
Nature Finds A Way Of Surviving
The coral reefs provide a vital ecosystem for underwater life, protect the coastal belts by reducing the power of waves crashing onto the coast, and are a sustainable source for millions around the world. They alone account for a third of all biodiversity in the oceans and over 500 million people depend on them for food and income. But widespread bleaching caused by rising sea temperatures is threatening the very existence of the corals.
The algae, so intrinsically linked to the survival of the corals, need to be replaced quickly, or the corals will perish. The last three decades alone have seen the destruction of over half the world’s corals. The world instance of coral bleaching was between 2015 and 2017.
Though the glowing coral reefs are a sign that they are under severe stress, the technicolor display are a sign of conditions that allow the corals to return.
Corals first turn white as they lose the algae. This causes an excess amount of light to reach and bounce off the reflective skeleton. The pigment process takes place only under slight temperature stress. But it is an encouraging sign that corals can recover and reunite with their partners. The symbiotic relationship between a plant and an animal is fascinating and their collaboration that produces a stress response beneficial to the partnership is even more so.