Resilient reefs may have some ability to resist climate change and adapt to the changing conditions or recover from these disturbances. In their weakened state, these corals reefs will be further compromised by more frequent tropical storms and rising sea levels. Assuming current trajectories, by mid-century bleaching episodes are predicted to be annual events affecting most reefs, and by the end of the century, atmospheric carbon dioxide levels will have changed ocean chemistry causing acidification, weakening the calcium carbonate skeletons of corals and slowing their growth. Estimates indicate that 75% of the world’s reefs are already threatened by local threats combined with rising sea surface temperatures and mortality from coral bleaching.Įven the remote reefs of the central Indian Ocean and north-west Pacific are now weakened, and vulnerable to disease. The most severely threatened reefs are in South-East Asia and the Atlantic, but even the Indian Ocean, Middle East and wider Pacific are now suffering from direct human impact. We must remember that the majority of coral reefs, especially those close to large human populations, are already degraded due to localised impact from over and destructive fishing, nutrient run off from urban and agricultural land, and coastal development. The producers understandably visit the best and most pristine reefs in the world to capture these wonderful sequences. In the last scenes, narrator David Attenborough provides a glimmer of hope as he describes corals and other reef species spawning on mass to produce new generations of life to build new reefs. Since 2014, an unprecedented series of consecutive warming events driven by climate change, have affected many reefs, including the Australian Great Barrier Reef, and annual bleaching is predicted to become more frequent, leaving no time for the reefs to recover between these extreme events. Prolonged bleaching leads to the death of the colonies that build the reef, leaving behind lifeless ruins. Inevitably, the episode described how these cities are under threat, as warming oceans destroy the symbiotic relationship between the corals and the algae living within them, causing the corals to lose their algae, and become bleached. Other reef species team up in unlikely partnerships to improve the outcome of a hunt for fish amongst the coral, as shown by the pointing display of an octopus working in cahoots with a grouper. : (C) Alex Mustard -© BBCCompetition is rife, as exemplified by the ferocious jaws of the metre-long bobbit worm, ready to pounce on unsuspecting fish by night from its lair in the sand, or the pulsating show of colours of the cuttlefish as it stalks a mesmerised crab. These reefs, analogous to bustling cities, are powered by sunlight, and provide space and services for a wealth of marine life.Ī bustling coral reef in Fiji. The third episode of the BBC’s Blue Planet II spectacularly described a series of fascinating interactions between species on some of the most pristine reefs in the world. This article by John Turner, Professor & Dean of Postgraduate Research, School of Ocean Sciences was originally published on The Conversation.
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