Global Bleaching Event Underway
October 12, 2015 9:56 AM   Subscribe

The world's coral is suddenly and rapidly starting to die - "This is only the third time we've seen what we would refer to as a global bleaching event. [The prior events] were in 1998 and 2010, and those were pretty much one year events. We're looking at a similar spatial scale of bleaching across the globe, but spanning across at least 2 years. So that means a lot of these corals are being put under really prolonged stress, or are being hit 2 years in a row." Can 'manually breeding supercorals capable of living in increasingly inhospitable waters' help in time? (via/via)
posted by kliuless (18 comments total) 13 users marked this as a favorite
 
The missus and I were in the Virgin Islands during the 2010 bleaching event, though we didn't know it. The water was strikingly warm and comfortable--lovely at the time, sinister in retrospect.
posted by Zerowensboring at 10:04 AM on October 12, 2015 [1 favorite]


I especially enjoyed the Shell Oil greenwashing ads that appeared alongside that story.
posted by slogger at 10:40 AM on October 12, 2015 [9 favorites]


From the manual breeding link, Some experts are concerned that these supercorals will outcompete the native ones seems like an odd way to express the concern, given that the whole point would be to make a coral that survives while the others are dying.
posted by meinvt at 10:42 AM on October 12, 2015 [1 favorite]


"Manually breeding supercorals capable of living in increasingly inhospitable waters" sounds like the beginning of a SyFy movie. Coralcuda, maybe? Pteracoral?
posted by amarynth at 10:49 AM on October 12, 2015 [7 favorites]


The Supercoral article mentions breeding the resistant corals, but (and IANACoralScientist but...) I believe they're still going to need stronger zoothanthellae algae to resist the higher water temps, or whatever it is that has the coral polyps all in a tizzy. What they glossed over is that the corals aren't necessarily dying due to the higher water temps - they can recover from a bleaching event. What's happened is the algae is gone (which gives most corals their color - hence the "bleaching" name for the event) due to an imbalance in *something* in the water - temp, salinity, chemicals, happens for lots of reasons. So, sure, breed a stronger coral animal, but what about the symbiotic algae that keeps it alive through photosynthesis during the day? (Nerdy details on how coral works from NOAA)
posted by danapiper at 11:04 AM on October 12, 2015 [5 favorites]


"Manually breeding supercorals capable of living in increasingly inhospitable waters" sounds like the beginning of a SyFy movie. Coralcuda, maybe? Pteracoral?

Coralnado.
posted by You Can't Tip a Buick at 11:33 AM on October 12, 2015 [5 favorites]


The water was strikingly warm and comfortable--lovely at the time, sinister in retrospect.

The water in the Virgins is always relatively warm, AFAIK.
posted by grumpybear69 at 11:40 AM on October 12, 2015


The estimate given in the first article -- 5% of the entire world's coral dead in the space of a single year (2015) -- is insane. Does anyone know what the larger effects would be of suddenly having no more coral in the oceans?
posted by demonic winged headgear at 11:59 AM on October 12, 2015 [1 favorite]


Massive marine ecosystem upheaval?
posted by blucevalo at 12:26 PM on October 12, 2015


Is warm water a separate issue from ocean acidification? From what I understand, higher CO2 concentrations in the ocean are also highly detrimental to corals, but I didn't see it mentioned here.
posted by indubitable at 12:43 PM on October 12, 2015




White is the color of death.
posted by qcubed at 1:14 PM on October 12, 2015 [1 favorite]


Not to be a downer, but if you have young kids and you're able, maybe take them snorkling to a coral reef. It's only going to get rarer, and it's frighteningly possible that within their lifetimes, that underwater beauty will pass into the history books.
posted by anonymisc at 2:01 PM on October 12, 2015


It's not just coral, either. In the last few decades, we've lost half of all fish.
posted by CheeseDigestsAll at 2:14 PM on October 12, 2015 [3 favorites]


Man, humanity sucks.
posted by Ray Walston, Luck Dragon at 2:53 PM on October 12, 2015 [1 favorite]


Is warm water a separate issue from ocean acidification?

On a system scale, water temperature and ocean chemistry are intricately coupled. In this case, temperature affects CO2 solubility as an inverse function, so the cooler the water, the greater the solubility.

Oceanic water wants to take in CO2 as part of the carbonate pump, which is driven by processes both biological (50% by plankton alone) and physical. When ocean water takes in CO2, CO2 reacts w/ H2O to form different components of what's called dissolved organic carbon collectively: free CO2, carbonate, bicarbonate, and carbonic acid. The ratio that gets formed is also a function of pH and temperature; more basic, carbonate dominates; the more acidic, CO2 (and thus carbonic acid) dominates.

Increase in carbonic acid increases the acidity of the water through a chemical reaction; therefore higher atmospheric CO2 concentrations increase acidity of the water. Higher acidity affects carbonate communities like coral because a) it affects the ratios of the CO2, Ca, and other mineral species to be taken in to form structures and b) they're more vulnerable to acid breaking down their structures.

Normally, the ocean system strives toward a balance - too much CO2 and the system works back to becoming alkaline. In very simplistic terms the physical and biologic processes balance atmospheric CO2 and a "natural" ocean pH in a process called carbonate compensation. When ocean circulation - the transfer and movement of colder, denser seawater up to the surface and moved around in what's called the ocean conveyor belt - is working correctly, CO2 is driven to the colder water masses where it can dissolve. But because it's a pump, when that deeper water finally upwells it will outgas that CO2. To actually get carbon fixing - i.e. to take in excess atmospheric CO2 and sequester it - requires biological processes.

Warmer water also affects ocean circulation - one of the possible effects of global warming will be changes in ocean circulation, including possible stratification and delays or outright stoppage of mixing the different salinity and temperature gradients. It also affects nutrients and the circulation of other minerals like magnesium for species like corals and plankton. Stratification also means that less atmospheric CO2 is sent through the ocean conveyor belt to the oceanic interior; the oceans become resistant to taking in CO2.

So a coral bleaching event is a great example of the 1-2 punch of increased CO2. Increased atmosphere CO2 increases oceanic temperature and affects circulation, but also - until it reaches its saturation point - increases acidity of the oceans. Warmer water kills off the symbiotic algae and thus coral are much more vulnerable to factors like diseases and storms as well as structural breakdown from increased acidity until they recover (if they can). Reefs as whole could also become more vulnerable to keeping up with sea level change. Due to the temperature/solubility relationship, warmer water then takes in less CO2 (affecting atmospheric temps), but the availability of carbonate for structure and their vulnerability to dissolution of the very organisms that need to sequester atmospheric carbon have been affected.

It's important to note that this has happened before; in those cases organisms and the ocean/atmospheric carbon pump, though wobbly with some fascinating results, have managed to recover into a form of equilibrium. (Not without some extinctions and ecosystem change, naturally.) The crux is the rate of change, and the system appears to be changing faster than we've observed in the rock record. There's also some significant disagreements research being done on how different factors will impact different organism communities, including coral reefs.

(I'd like to note that this is very simplistic - it ignores factors like pressure, freshwater inputs, the natural weathering of rocks on land and the carbonate compensation depth.)
posted by barchan at 4:02 PM on October 12, 2015 [15 favorites]


From the Christian Science Monitor:

If reefs were to disappear, commonly consumed species of grouper and snapper could become just memories. Oysters, clams and other creatures that are vital to many people's diets would also suffer. And experts say commercial fisheries would fail miserably at meeting demand for seafood.

"Fish will become a luxury good," said Cassandra deYoung of the United Nations Food and Agriculture Organization. "You already have a billion people who are facing hunger, and this is just going to aggravate the situation," she added. "We will not be able to maintain food security around the world."

posted by MrVisible at 5:40 PM on October 12, 2015 [2 favorites]


Manually breeding supercorals capable of living in increasingly inhospitable waters" sounds like the beginning of a SyFy movie. Coralcuda, maybe? Pteracoral?

Mrs. Pteracoral (mefi's own)
posted by ActingTheGoat at 7:30 PM on October 12, 2015


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