In the summer of 2019, a coastal reef in the UAE experienced recurrent hypoxic events – moments when the amount of oxygen dissolved in the water is depleted and falls rapidly – which can pose adverse effects to the long-term maintenance of a thriving ecosystem. This is according to the latest study conducted by NYU Abu Dhabi (NYUAD) researchers. 

NYUAD Associate Professor of Biology John Burt and Associate Professor of Mathematics Francesco Paparella, together with the researchers Alain De Verneil and Matthew Mitchell, studied a reef in the southern Gulf. The study, published in Frontiers in Marine Science, revealed interesting data which in the future with further research could help investigate the extent of the hypoxic events, whether they occur in other marine environments, and their consequences on the ecosystem. 

A mathematical model applied to the observed oxygen and temperature data, taken at different depths on the same location,  led scientists to conclude that microbial communities at the bottom of the water column appear to be the largest consumers of oxygen, which during the day is replenished by photosynthesis, but at night may drop to dangerously low levels. These drops, so far, do not last long enough to cause widespread mortality on the reef, but they cause stress to the ecosystem, and are very likely to be a contributing cause to summer coral bleaching.

 

“Predicting future Gulf hypoxia risk for coral reef ecosystems requires diagnosing the underlying causes driving the timing and magnitude of oxygen swings. The Gulf today experiences temperatures expected to occur across much of the tropics by the end of the century, and the observation of recurrent hypoxia events in the Gulf during summer suggests that similar hypoxic phenomena may represent an important, but to date, underappreciated threat to the future of global coral reefs.”

 

“What we discovered is very surprising, given the shallowness of the water column above the reef, and the fact that it is being continuously mixed by tides and wind-driven waves. It's only thanks to John's intuition that led him to put oxygen sensors where no one would have suspected hypoxia could occur, that we now have the first glimpses of this phenomenon.”