The Great Barrier Reef is experiencing severe bleaching

Australia's Great Barrier Reef is experiencing one of the worst bleaching events since we started monitoring its activity and much of the fauna already shows serious signs of damage due to rising ocean temperatures around the world.The Australian authorities announced this, adding that scientists are still quantifying the high cumulative and irreparable damage resulting from the event.According to the data, the phenomenon reached record ocean depths and the Great Barrier was subjected to a higher level of heat stress than in any six previous mass bleaching events.“The Great Barrier Reef is an incredible ecosystem and, although it has demonstrated its resilience time and again, this summer has been particularly challenging,” commented Roger Beeden, the authorities' chief scientist.

The coral bleaching it is that destructive phenomenon that can lead to the death of coral reefs and their ecosystems as the symbiosis between coral polyps and some unicellular algae is missing.After having expelled the symbiotic algae, the structure "bleaches" and, in the absence of the only source of nourishment, the polyps are destined to starve.The main causes of bleaching lie in ocean warming:And due to stress generated by heat or pollution that corals expel microorganisms and interrupt the symbiosis.According to i data referring to the bleaching of 100 locations around the globe, the phenomenon is recorded more frequently during the phases of the El Niño-Southern Oscillation climatic phenomenon and has significantly increased from the 1990s to today.To counteract whitening, the only solution is ensure survival of corals: only a barrier where the polyps are not yet dead can fully recover ensuring the right conditions for a sufficient time.Otherwise, as underlined by the scientists who raised the alarm, the damage could be irreparable.

A few days after the alarm on the increase in global ocean temperatures launched by the National Oceanic and Atmospheric Administration and the International Coral Reef Initiative - respectively the US scientific and regulatory agency for the sector and a global partnership for the protection of coral reefs – the Australian authorities they revealed that the Great Barrier Reef is experiencing one of its worst bleaching events in decades:73% of the reefs examined in the park present "prevalent bleaching", i.e. present in over 10% of the coral cover of each reef examined, while “very high and extreme” bleaching was observed in nearly 40% of the ecosystem, i.e. in over 90% of the coral cover of each reef.According to scientists, climate change is among the causes:«Climate change is the greatest threat to the Great Barrier Reef and to coral reefs globally», they say the experts, adding that the phenomenon could be the largest test yet of the resilience of one of the wonders of the world.«The southernmost parts of the reef, which had previously been largely spared, this time they were hit particularly hard, with bleaching affecting many more species, extending to greater depths and affecting some of the oldest and most resilient corals.This is a disaster on our doorstep,” commented Simon Bradshaw, a research director at the Australian non-profit organization Climate Council.

[by Roberto Demaio]