Weather-related coral deaths at the Great Barrier Reef will increase this summer, according to a University of Queensland study.
For the study, researchers examined the Porites coral colonies or 'bommies' in the Great Barrier Reef.
The Colonies can thrive for several centuries and grow to several metres in diameter. Porites provide important habitat for reef fishes and are deemed to be more resilient to environmental changes than other coral communities. The Colonies function as valuable recorders of past environmental change.
Researchers said that understanding the effect of global warming on climate-resistant corals provides insight into the declination of the Great Barrier Reef in the future.
"We found that there has been a significant correlation between the timing of deaths in the Porites colonies and unusually high sea-surface temperatures in the past 150 years, as well as an increased frequency of deaths in the past thirty years" said Dr Tara Clark, lead author of the study, in a statement.
Researchers used a modified uranium-series dating method to determine coral deaths. They said that by learning the timing of their deaths, the probable cause of their demise can be known.
Researchers found that coral deaths occurred in large numbers during environmental disasters like global bleaching event of 1997/1998 and two Burdekin River floods.
"The 1997/1998 bleaching followed a strong El Niño event on top of a decline in water quality and a long-term global warming trend, which seems to have pushed the most robust corals past their tolerance limit," said Professor Jian-xin Zhao, project leader. "Considering that a similar El Niño event is predicted to occur this coming summer, we have grave concerns for the reef."
