Rising ocean temperatures are wreaking havoc on the organisms that live there, and one only needs to look to coral reefs to see the extent of the damage. Severe coral bleaching events could become increasingly regular, but a new study has revealed a glimmer of hope. Some species of coral – but by no means, all of them – appear to be adapting to the warming waters, with researchers finding less bleached coral in a 2016 event than under similar circumstances in 1998.
Last year was a bad year for coral. Unusually warm water puts a lot of stress on the organisms, and in response they discharge vital algae, which robs them of nutrients and color. The resulting paleness, known as bleaching, paints a pretty clear picture of an ailing reef, and reports suggest the condition affected about 60 percent of the world's coral in 2016, including huge swathes of Australia's Great Barrier Reef.
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While there are indications that these kinds of events might become more regular in the near future, a new study by the Wildlife Conservation Society has found some good news among the bad. Examining two marine national parks in Kenya, which were among those affected in last year's bleaching event, the researchers found a significant decline in the number of bleached coral colonies, when compared to a similar event in 1998.
Out of 21 coral species studied, 11 appeared to be hardier against bleaching than they were 20 years ago. In one park, the number of bleached coral colonies dropped from 73 percent in 1998 to just 27 percent in 2016, while the other park fell from 96 to 60 percent. Encouraging as that sounds, the rest of the species studied weren't handling the changes well, with one seeming more vulnerable to bleaching now than in the past.
"This was a rare chance to study bleaching responses during two separate times with very similar conditions," says Tim McClanahan, author of the study. "Adaptation is evident for some of the more important reef building corals but, sadly, many species are not adapting, so this is a good news-bad news story. Evidence for adaptation in the past is not evidence for adaptation in the future. Nevertheless, I suspect this adaptation to hot water started before my 1998 work and could have begun during the 1983 and 1988 El Niños, when coral bleaching was first observed in the region."
The research was published in the journal Marine Ecology Progress Series.
Source: Wildlife Conservation Society