While scientists have repeatedly cautioned over excessive ‘bleaching’ of coral reefs due to global warming, a new study has revealed that some of the corals have developed a ‘sunscreen’ to protect their skeletons against the rising sea temperature.
Many of these marine invertebrates have algae embedded in their cells that help them survive in challenging conditions. However, the rising sea temperature can lead to an imbalance and loss of algae, leaving the corals limestone exposed to the sunlight. This often results in the death of the deepwater organisms.
The study by researchers at the University of Southampton published in Current Biology states that as per their observations, some of the corals were producing a ‘sunscreen’ in the form of a colourful display as a response to mild heating conditions. The coral normally loses its colour when the temperature underwater reaches 30-31 degree-Celcius and if the warm conditions persist, they die. However, now the scientists have found that the lost algae are retrieved by some corals by its neon colours and have even called this phenomenon ‘optical feedback loop’.
Professor Jorg Wiedenmann explained: "Our research shows colourful bleaching involves a self-regulating mechanism, a so-called optical feedback loop, which involves both partners of the symbiosis [the coral and the algae].”
Meanwhile, a research carried out at Bangor University suggested that the Amazon Rainforest could be gone in about 49 years and the coral reefs could be bleached in the next 15 years. The researchers analysed the changes of 25 marine, 13 freshwater and four land ecosystems to find out how long it would take for them to reach a critical point.
Dr Simon Willcock, a joint lead author on the study, from Bangor University's School of Natural Sciences, said that the changes represent a threat to human life. The scientists have said that once a 'tipping point' is triggered, large ecosystems could collapse much faster.