Ecological diversity in the Great Barrier Reef has ‘systematically declined’ and is showing few signs of recovering to its previous state, according to a major study which looked at the Reef over the past 91 years.
The survey began in 1928 when the Great Barrier Reef Committee and the Royal Society of London sent an expedition to study the Great Barrier Reef.
This expedition was so carefully recorded, that scientists at Barllan University, Israel and the University of Queensland, Australia, have been able to go to the exact same spot and identify features that the 1928 expedition saw.
In 1928, scientists believed that it was ‘unlikely’ that temperatures would ever become high enough to kill the coral. However, since 1928, sea surface temperatures have increased by 0.7 degrees Celcius which has had a devastating effect on coral diversity.
Specifically, massive corals have replaced branching corals, and soft corals have become much more common.
Since then, seawater pH is also lower by about 0.1pH units, sea levels are now 20cm higher and severe flooding occurs more frequently.
Scientists say climate change has pushed many coral reefs close to collapse over the last few decades and their ability to fully recover is now uncertain.
Coral reefs across the world such as the Great Barrier Reef and the UK’s Chagos Marine Reserve are more and more susceptible to coral bleaching caused by cyclones, making recovery between disturbances more important.
Prof. Maoz Fine at Barllan University said: ‘The degree to which reefs may shift from one state to another following environment change was overwhelming.’
‘The long-term implications of these changes highlight the importance of avoiding phase shifts in coral reefs which may take many decades to repair, if at all.’
The study ‘Ecological changes over 90 years at Low Isles on the Great Barrier Reef’ was published today (September 27) in the journal Nature Communications.
A study published earlier this year in the journal Nature, found that chronic exposure to poor quality water quality rate is affecting the recovery rates of corals in the Great Barrier Reef, slowly putting it under threat.
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