Just as we mortals crave a cooling breeze during a hot summer, so does our iconic Great Barrier Reef.
Scientists from Melbourne’s Monash University have found that the collapse of trade winds was a major factor in recent coral bleaching events impacting the reef.
PhD candidate Lara Richards said the cause behind the spike in ocean temperatures resulting in coral bleaching had previously been unclear and was often linked to El Niño.
However, Ms Richards said an analysis of more than three decades of atmospheric weather had unlocked the role the easterly trade winds had in regulating the temperature of the reef.
She said a case study of a mass bleaching of 91 percent of the reef in February 2022, the fifth in eight years, provided the breakthrough.
“Our research has identified that it was the collapse of the trade winds that drastically altered the near-surface temperature of the ocean,” Ms Richards said.
“During a three-week period, we observed the ocean warming in this area by almost 2C to 30.5C, as the absence of the trade winds allowed a decrease in cloud cover, increase in solar radiation, and lack of evaporative cooling.
“Following the re-establishment of the trade winds, the warming ended abruptly and the ocean temperature cooled by 1C over 48 hours as evaporative cooling effectively tripled.”
Ms Richards said the findings highlighted the exacerbating impact of local meteorology on coral reefs and provided never before seen clues to help combat the impact of coral bleaching on the reef.
“Now that we understand the conditions that can lead to bleaching events, we will be able to predict where and when they will occur, and put in place measures to respond to and mitigate their impacts.”
She said in identifying the cause of key incidents of ocean temperature increases that caused coral bleaching, the research also helped dispel myths around links to El Niño.
“People tend to associate coral bleaching on the Great Barrier Reef with El Niño, which we’ve now been able to demonstrate is misinformation.”
Read the full report: The meteorological drivers of mass coral bleaching on the central Great Barrier Reef during the 2022 La Niña.
