As a consequence of climate change, the Great Barrier Reef in Australia is experiencing the largest annual decline in coral coverage in 39 years, according to the annual report from the Australian Institute of Marine Science (AIMS).
This loss is mainly caused by thermal stress induced by global warming. This climatic phenomenon led to coral mortality due to the massive bleaching event of 2024, in addition to the impact of cyclones and outbreaks of crown-of-thorns starfish.
According to the annual report, the coral coverage of the Great Barrier Reef decreased between 26 and 40% depending on the areas. Furthermore, the statement adds that the record losses of coverage this year started from a high baseline, resulting from the high levels reached in recent years.
On the other hand, the document explains that there was observed greater volatility in the levels of hard coral coverage, which is considered a sign of a stressed ecosystem. They even added that the fluctuations between historical lows and highs occurred in a relatively short period, whereas before they occurred more moderately.
The consequences of a new massive bleaching
According to the annual summary of the Long-Term Monitoring Program (PML) of AIMS, which collected data from studies of 124 coral reefs conducted between August and May 2024, 77 of them recorded a hard coral coverage between 10 and 30%.
Furthermore, 33 reefs had a hard coral coverage between 30 and 50%, while two had a coverage above 75%, and the last two reefs had a coverage below 10%.
It was also detailed that the massive bleaching of the Great Barrier Reef in 2024 represented the fifth event of this kind since 2016, although it is the first to affect almost all coral reefs in Australia.
This research revealed that massive bleaching events are becoming more frequent and intense, as it is the second time in a decade that corals experience this phenomenon in two consecutive years.
A discouraging phenomenon
Massive coral bleaching occurs when corals expel the symbiotic algae that provide them with nutrients and color, usually in response to water temperature increases. Without these algae, corals lose their main source of energy and become weakened, compromising their ability to grow and reproduce.
The loss of corals directly affects marine ecosystems, as many species of fish, crustaceans, and mollusks depend on them for shelter and food. When coral structures deteriorate, biodiversity decreases, and the trophic chain is broken, generating a cascade effect throughout the marine community.
Furthermore, the degradation of reefs reduces their ability to protect coasts from erosion and storms. This puts at risk human communities that depend on these natural barriers, not only for coastal safety but also for economic activities such as fishing and tourism.
