- a 2015 study found there is no techno-fix to prevent a catastrophic collapse of ocean life for centuries if not millennia if we continue current CO2 emissions trends through 2050.
A study published in May 2017 tells us that oxygen is depleting in the oceans two or three times faster than expected.
- by combining oxygen loss with ever-worsening ocean warming and acidification, humans are re-creating the conditions that led to the worst-ever extinction, which killed over 90 percent of marine life 252 million years ago.
Wikipedia on the Permian–Triassic extinction event:
- The Permian–Triassic (P–Tr or P–T) extinction event, colloquially known as the Great Dying, the End-Permian Extinction or the Great Permian Extinction, occurred about 252 Ma (million years) ago, forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras. It is the Earth’s most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It is the only known mass extinction of insects. Some 57% of all families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event, possibly up to 10 million years.
Then as now the problem started on land, that time with severe volcanism. However, then too methane clathrates became involved. We don’t really know whether it will be worse or better this time, but what we are heading for looks so bad that it doesn’t really matter.
- As National Geographic reported in 2015, we’re already starting to see the impacts of anoxia. “The waters of the Pacific Northwest, starting in 2002, intermittently have gotten so low in oxygen that at times they’ve smothered sea cucumbers, sea stars, anemones, and Dungeness crabs,” the magazine reported.
That article goes into the complex factors at work, and there is a variety of scientific opinion:
Many scientists already suspect global warming is partly to blame for this transformation. Deutsch and others, however, think oxygen declines so far have been driven by complicated natural factors. Ocean conditions vary so much normally that they might be experiencing an unusual period of depletion—one that could moderate soon.
But Deutsch called that “a very, very thin silver lining.”
The larvae of strange but important midwater fish like the black sea dragon have declined off California as low-oxygen regions have expanded.
“Right now in the ocean, there is incredibly strong internal variability and a very tiny climate trend on top of it,” he says. “But my sense from all the model simulations we’ve done is that we’re on the verge of having that trend emerge from the noise.”
The simple fact remains, however, that warmer waters hold less oxygen and anoxic zones are appearing and growing at an alarming rate. This image gives some idea:
The black patches represent incomplete data.
The 2017 study has raised the level of alarm finding that ocean oxygen was falling more rapidly than the corresponding rise in water temperature. It pays to take notice of Hans Joachim (John) Schellnhuber, Director of the Potsdam Institute for Climate Impact Research, Professor for Theoretical Physics at the University of Potsdam, Senior Research Fellow at the Stockholm Resilience Centre, and Member of the German Advisory Council on Global Change (WBGU):
- If we don’t start slashing carbon pollution, then, as co-author John Schellnhuber put it, “we will not be able to preserve ocean life as we know it.”
Now it looks as though we are Losing Nemo. Increased acidification robs clownfish of their hearing and sense of smell. Presumably other species will be similarly afflicted.
The Permian–Triassic extinction event included about 60,000 years of acidic oceans. On land whether Homo sapiens survives may be put to the test. However, in the long run not all may be lost. Mammals in their modern for really started their journey about 30 million years after the Great Dying. When given a chance mammals diversify quite quickly, so some millions of years down the track another species that is wise as well as clever may appear.
9 thoughts on “Oceans heading for mass extinction”
Brian: Coral will extract CO2 from the ocean and lock it up in calcium carbonate. Whoops!!! What did you say about coral bleaching? And cement manufacturing driving the CO2 out of calcium carbonate to make cement?
Coral erodes and acretes as you would expect. Over time coral loss more or less balanced coral loss.
“Calcium carbonate is deposited as the aragonite polymorph, and is stabilized into a continuous calcareous skeleton by colonies of hexacoral polyps covering the surface of the reef…:
To build coral, the sea water needs a concentration of aragonite which is basically carbonate. Ocean acidification lowers the saturation levels of aragonite thus inhibiting coral regeneration.
That has tipped the balance towards coral loss. That is not coral bleaching, but it is relevant to the recovery of reefs.
GB: Coral reefs build up until they reach the surface. If the ground is sinking or the reef hasn’t reached the surface it will continue to build up. The thick limestone deposits in many parts of the world are a record of this building up. Limestone can build up without biological help (think limestone cave formations.) but in the case of coral it is the coral polp that drives the process by extracting CO2 from calcium bi-carbonate.)
John and Geoff, I’m not sure why we are talking about corals in this context. Seems they have been around for around 500 million years and come and go for sometimes unaccountable reasons.
If you’d asked me, I would have said they were wiped out during the Permian–Triassic extinction event and took about 4 million years to reappear. Seems they made an appearance around 1.5 million years after the wipe-out, but took a lot longer to reach substantial levels. However, apart from coral reef species, of which there are of course many, they are a sideshow, albeit a spectacular one.
JD the polyps are certainly the builders of coral, but they need a source of calcium. The level of aragonite in the water is linked to the rate at which polyps can build. (other things influence too of course)
Brian I guess coral is a bit front-of-mind up here, it is a more easily seen barometer of ocean health. But it is a big topic. Last weekend a group (Tangaora Blue) cleaned up the garbage on Kimberly beach, just north of the Daintree ferry. The haul was about 380 kg of stuff, mostly plastics from as far as SE Asia. That beach is cleaned every 3 months so that’s about 1200 kg per year on just one beach.
A very recent paper in “Science” identifies plastics as making coral twenty times more susceptible to disease.
Brian: My recollection is that when reefs rebuilt after great dyings the reef building organisms were competently different from the ones that were wiped out. If you like a new group of reef builders had to evolve hence the large gaps where there was no significant reef building.
I would also make the point that a lot of fossil carbon is stored as limestone.
We need to grow the carbon sinks as well as keeping the sunk carbon safely where it is.
Geoff, if I was as up to date as I’d like to be I’d be posting about the GBR as several stories have flown by without me capturing them.
My general impression is that we must do what we can, but the proxcimal things we can do will be overwhelmed by the big ones – increased warming and acidity.
There does not seem to be an appreciation among pollies that about 100% of reefs will be affected by the time we reach 1.5C and that will happen almost certainly in the next 30 years.
John, it seems logical the reefs with their great diversity would evolve differently after a wipe-out from a few isolated remnants.remnants.
I was impressed by the David Attenborough TV programs on the GBR and other reefs. The history showed former reef material could be found at all sorts of depths, depending on past sea levels, past climates.
I realise it may not be very reassuring for contemporary GBR tour operators and hotel owners, but my long-term view is that coral reefs are, as systems, very resilient and dynamic.
Perhaps aided by the gigantic annual breeding event, where billions of tiny creatures spurt into the seas, to drift who knows where…..
Perhaps that huge release guarantees that millions will reach an hospitable habitat and latch on to grow, whatever current physical, geochemical conditions are like???
Not surplus, not wasteful, rather: an insurance mechanism for long-term adaptation and hence survival??
That’s just a suggestion.
(Don’t get me wrong. I don’t want dead oceans or dead seas.)
Nobody – well, almost nobody – has heard of the Permian-Triassic Extinction. The only extinction in the public mind seems to be the end of the Cretaceous and the disappearance of all those lovely dinosaurs.
There is a need for all of us to mention the great Permian-Triassic Extinction so that people we know personally are aware that it happened and what its effects were. We can’t depend on the news and entertainment industry to do that. What’s more, there is fat chance that any scientists will have much luck in making the public aware of it – and of how relevant knowing about it is to us in this age
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