these bleaching events do occur from time to time, but this one was the most severe. researchers are also measuring a slowdown of coral growth associated with ocean acidification. scary stuff, when the reef is finally gone, it’ll be far to late to have done anything about it. we really need to act now.
SFGate? I though they fell off the left wing-end of the spectrum(?)
Now, how to blame it on Trump…
Given that Coral originated 540 million years ago, has survived numerous catastrophic extinction events, some which killed around 96% of all marine species, and has effortlessly survived hundreds of millions of years of abrupt natural changes in global temperature, I think the burden of proof is on marine scientists to demonstrate why the distinct lack of warming is causing this bleaching?
Or could it be coastal development and ag runoff?
From what I am reading, the region North is where temps had risen. The south was said to benefit from a cooling helped by a tropical cyclone.
My temp data would indicate temp increasing is not the cause. The claim is that this is a persistent harm to the coral, so a temporary weather event (cyclone) would make no difference.
However, your map shows the death is fairly localized to the “North” section, which would indicate other causes, probably man made environmental impacts.
Yes. The damage certainly is a localized event. It has been reported the 2015-16 El Niño is the suspected cause of the northern area coral bleaching. Though, I am sure studies will continue.
The good news is the Northern area may recover.
“Most of the losses in 2016 have occurred in the northern, most-pristine part of the Great Barrier Reef. This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected,” says Professor Terry Hughes, Director of the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies based at James Cook University, who undertook extensive aerial surveys at the height of the bleaching.
“The good news is the southern two-thirds of the Reef has escaped with minor damage. On average, 6% of bleached corals died in the central region in 2016, and only 1% in the south. The corals have now regained their vibrant colour, and these reefs are in good condition,” says Professor Andrew Baird, also from the ARC Centre, who led teams of divers to re-survey the reefs in October and November.
Scientists expect that the northern region will take at least 10-15 years to regain the lost corals, but they are concerned that a fourth bleaching event could happen sooner and interrupt the slow recovery.
El Nino is a powerful thing that affects flora and fauna profoundly on land. I don’t know of a reason to think it’s less so in the ocean.
My impression is that the single most important cause of coral death is the crown of thorns starfish, which eats the living parts of the coral as well as the plankton that feeds the coral. Apparently the starfish proliferate more in areas where fishing is heavy, because various predator fish eat the crown of thorns in their tiny, early stages.
There are speculations that fertilizer runoff is also part of the cause.
undoubtedly it’s multifaceted.
I suspect fertilizer run-off is a big player in this event. Watching the news, it sounds as though relevant agencies are working to change the habits of farmers to greatly reduce impacts to the reef. One large farm near the ocean was recently bought out, and is slated for conservation.
There is also work being done by science to find an effective means of rehabilitating the reef, much like precious wetlands are rehabilitated with native species and nurtured.
Can’t comment on whether the weather is to blame, but the El-Nino is likely a big player. It is unlikely La Nina is likely to form, based on reports by the BOM here in Australia, so the reef won’t get too cold either. bom.gov.au/climate/enso/index.shtml#tabs=Overview
This year is meant to be above-average for tropical cyclones, so that could impact on the health of the reef, too.
Act now and do what?
The really sad issue is that coral reefs are like the rainforests of the sea in that they host a very large variety of species, one of the most diverse ecosystems on the planet. See floridakeys.noaa.gov/corals/biodiversity.html. So this also means harm, death, and extinction of species.
Now oceanographers are saying that life in the oceans around the world is already dying out from a number of environmental assaults, including pollution, climate change (warming oceans), and the concomitant effect of ocean acidification from carbonic acid, plus overfishing, dumping of wastes, eutrophication, micro-plastics from wastes and laundering of synthetic clothes & going up the food-chain, etc.
We don’t see all this because it is underwater. We only see the beautiful oceans on the top and think all is fine.
There is natural regrowth of coral.
Hard to believe.
[The ocean is not acidifying. By the way. More bogusness.]
Here is a better discussion and explanation of ocean acidification. They say it’s becoming less alkaline, so in that way you are correct…it’s not acidic!