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The most diverse corals of the South Atlantic, Brazil's Abrolhos, are declining as the climate warms

Researchers in Rio de Janeiro reported that the coral cover on Brazil's Abrolhos reefs, which is the most biodiverse ecosystem of the South Atlantic, had fallen by around 15% in 18 years due to climate changes and human activity.

The climate change-linked heatwaves have intensified the so-called "bleaching events" where corals expulse the algae they call home. This permanently undermines the coral health.

Corals are dying because their health is compromised by the increased frequency of heatwaves. They may even regain color with this increase, but will develop diseases and necrosis. Coral reefs sustain about 25% of marine life around the globe, but are in a state of almost irreversible death. Scientists have called this the "tipping point" for climate-driven ecosystem collapse.

Scientists say that in order for reefs to recover, the world must drastically increase climate action and bring temperatures to just 1 degree Celsius below the preindustrial norm.

According to U.N. data and EU science agencies, global temperatures are already 1.3-1.4 degrees Celsius (2-3 degrees Fahrenheit above preindustrial levels) warmer than the average.

Brazilian researchers studied the Abrolhos Reefs from 2006 to 2023. The Royal Society Proceedings B journal published the results of this study. The findings show "insidious shifts in coral assemblages including the collapse branching corals."

The study found that while larger branching corals provide reef structure, they are being replaced with species that grow faster and offer fewer "ecological" benefits.

Moura stated that human activity is responsible for the worsening of the damage. The sediment created by the dredging of a nearby shipping channel in the Port of Caravelas damages the water quality and kills corals.

The report stated that local marine protected areas had not 'halted the corals decline. This indicates that, while they are fundamental in protecting biodiversity, it is 'not enough to face a global climate emergency.

Ricardo Gomes is a biologist from the Instituto Mar Urbano. He said that reefs are vital for fishing, tourism, coastal livelihoods and jobs.

Gomes stated that "putting Abrolhos in danger means putting all of the biodiversity along the Brazilian coast in peril." (Reporting by Sergio Queiroz in Rio de Janeiro; Writing by Oliver Griffin; Editing by Aurora Ellis)

(source: Reuters)