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idunno

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Oceanic anoxia
« on: January 04, 2018, 10:27:25 PM »
Perhaps the most terrifying aspect of the climate crisis is the trend towards oceanic anoxia, discussed here...

https://www.theguardian.com/environment/2018/jan/04/oceans-suffocating-dead-zones-oxygen-starved

It seems to me entirely probable that, if the oceans tip into an anoxic state, the atmosphere will necessarily follow.

I presume its also possible that, like a stagnant pond, the oceans could begin producing noxious gases such as hydrogen sulphide, nitrous oxide, etc, instead of oxygen. I vaguely recall an estimate that around 70% of the oxygen produced within the carbon cycle is the product of oceanic plankton...

As the article above concludes, "If you can't breathe, nothing else matters."

This has been mentioned in passing occasionallly on here, but I couldn't find a thread...

Avalonian

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Re: Oceanic anoxia
« Reply #1 on: January 04, 2018, 11:11:23 PM »
Indeed. Anoxic oceans have very unpleasant side-effects, as witnessed during the Permo-Triassic interval, for example. And yes, H2S is a major emission product under those circumstances, and has other effects as well: like ozone depletion.
http://www.homepages.ed.ac.uk/shs/Methane/Methane%20and%20hydroxyl.pdf

Basically, no, we don't want to see this happen.

AbruptSLR

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Re: Oceanic anoxia
« Reply #2 on: January 05, 2018, 03:44:48 PM »
The linked reference discusses the global trend of declining oxygen in the oceans:

Denise Breitburg et al. (05 Jan 2018), "Declining oxygen in the global ocean and coastal waters", Science , Vol. 359, Issue 6371, eaam7240, DOI: 10.1126/science.aam7240

http://science.sciencemag.org/content/359/6371/eaam7240

Abstract: "Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. These changes have accelerated consumption of oxygen by microbial respiration, reduced solubility of oxygen in water, and reduced the rate of oxygen resupply from the atmosphere to the ocean interior, with a wide range of biological and ecological consequences. Further research is needed to understand and predict long-term, global- and regional-scale oxygen changes and their effects on marine and estuarine fisheries and ecosystems."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Susan Anderson

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Re: Oceanic anoxia
« Reply #3 on: January 05, 2018, 09:39:40 PM »
Saw that horrifying article along with the dead coral developments and a few other nasties (along with the tide going humph and soughing almost up to my front door, a few years ahead of my "alarmist" ideas of when that would happen (Boston, low pressure contributed), which do not lead to a cheerful attitude.

Buy you put me in mind of an old but effective list of the problems we face, by SciShow, which had a vogue a few years back (may still, for all I know). The final item is about anoxia and paints a stark picture of the problem. If you only want the bit about ocean acidification and anoxia, skip to minute 6:20 and keep with it.

TerryM

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Re: Oceanic anoxia
« Reply #4 on: January 05, 2018, 11:35:42 PM »
Susan
Good to hear that your house wasn't (quite) inundated by all of that errant water and ice. Some of the photos from Boston made me feel much better about the blizzard like conditions we've been enduring. :D


I confess to having been distracted by your commentator's magically migratory mole. His familiarity with Sinatra's philosophy of purposefully produced & propelled footwear shows his propensity to peruse primitive premises, and this coupled with his concern re. the coming catastrophic climatic changes may explain his eagerness to experience a nascent, nudist era.  :(


Confused, Famine & fresh water, Sea level rise, Acidification, Thermohaline shutdown, 8:39 migratory mole movement! 9:49, and it's back, Awk!


Not sure why he chose that particular order, but it's a good synopsis for those only now beginning their journey of awareness, (and despair?).  :-\
Terry

Susan Anderson

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Re: Oceanic anoxia
« Reply #5 on: January 06, 2018, 08:39:57 AM »
Terry, it's a 6 story brick mill building converted to an artists' cooperative, and the water came up to the sidewalk but didn't come in. To seaward of us, the surge shocked the occupants of at least 30 expensive new highrises on what was formerly waste land. Boston is largely made land, though hilly as well, but the seaward lowlands and some areas that should be turned back to nature did not do well in this storm. It was a direct lesson in how low pressure raises sea level, and how close we are to the future of sea level rise.

Sorry you were distracted. The vlog brothers, Hank Green (and John) are quite well known in younger circles, and their style densely packs a lot of information. https://en.wikipedia.org/wiki/Hank_Green They offer a wide range of educational videos and are well informed.

As I do all too often, I offer an OT amusement, which I hope you will enjoy. My physicist father says the words are accurate, which is rather remarkable. No mole to distract you:

aperson

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Re: Oceanic anoxia
« Reply #6 on: January 07, 2018, 12:32:00 AM »
Enhanced H2S production alongside RCP 8.5 projected CH4 releases seems like we'd essentially be creating a Permian-Triassic style feedback loop to destroy ozone:

http://onlinelibrary.wiley.com/doi/10.1029/2006GL028384/full
Title: Role of hydrogen sulfide in a Permian-Triassic boundary ozone collapse

Abstract:
Using a three-dimensional chemistry-climate model of the troposphere and stratosphere, we find that hydrogen sulfide alone is unlikely to directly affect stratospheric ozone, even for hydrogen sulfide emission rates as large as 5000 Tg(S) per year. However, we also find that large quantities of hydrogen sulfide create a significant decrease in tropospheric hydroxyl radical, leading to a commensurate increase in atmospheric methane. Therefore a large methane flux (possibly from methane clathrate destabilization, Siberian traps or hydrothermal vent complexes) combined with a large hydrogen sulfide oceanic flux is much more likely to lead to an ozone collapse than methane or hydrogen sulfide alone with implications to the Permian-Triassic boundary extinction 250 million years ago.

-

If I understand correctly, lower hydroxyl concentration increases the GWP of methane since it is not removed from the atmosphere as rapidly. It also aids in stratospheric cloud production to destroy ozone.

TerryM

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Re: Oceanic anoxia
« Reply #7 on: January 10, 2018, 08:44:58 PM »
Terry, it's a 6 story brick mill building converted to an artists' cooperative, and the water came up to the sidewalk but didn't come in. To seaward of us, the surge shocked the occupants of at least 30 expensive new highrises on what was formerly waste land. Boston is largely made land, though hilly as well, but the seaward lowlands and some areas that should be turned back to nature did not do well in this storm. It was a direct lesson in how low pressure raises sea level, and how close we are to the future of sea level rise.

Sorry you were distracted. The vlog brothers, Hank Green (and John) are quite well known in younger circles, and their style densely packs a lot of information. https://en.wikipedia.org/wiki/Hank_Green They offer a wide range of educational videos and are well informed.

As I do all too often, I offer an OT amusement, which I hope you will enjoy. My physicist father says the words are accurate, which is rather remarkable. No mole to distract you:



Thanks Susan, and an apology for losing the thread.
Your living accommodations are envied. The old mills, in this region at least, invested heavily in glass so as to save on lighting. Hence they've made wonderful lofts and condos, and an "art cooperative" sounds ideal for intellectual stimulation.
Could I ask which "art" you pursue? My wife has an on again off again love affair with oil painting, but she's a wonderful sculptress with no interest in the medium. I bang away on a piano from time to time, but I'll go for months without touching the keyboard. Decades ago she'd write poetry, and I'd put them to music.


I had no idea how isolating apartment life could be. 16 floors effectively insulates one from the street, and ofttimes it's just easier to stay home with a book. Fortunately other options are open through political and social clubs, but I do miss sitting on the porch and interacting with the human traffic flowing past.


Assume your weather's back to whatever the new normal is? The "younger circles" I'm in contact with have mainly slipped into their 40's, so the vlog brothers slipped under my radar. Thanks for the heads up!
Terry

CDN_dude

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Re: Oceanic anoxia
« Reply #8 on: January 12, 2018, 04:09:23 AM »
I know Petrovskii has done some initial work on this issue. I'm not aware what the critical reception to his papers has been however. Here is an open access version of his most recent:

https://www2.le.ac.uk/departments/mathematics/extranet/staff-material/staff-profiles/sp237/conferences/jtb-2017b

"We show that, when the temperature rises sufficiently high, a regime shift happens: the sustainable oxygen production becomes impossible and the system's dynamics leads to fast oxygen depletion and plankton extinction."

I've also found that Jeremy Jackson of Scripps has some good interviews that help explain the crises oceans are facing (for non-experts): https://www.learner.org/courses/envsci/scientist/transcripts/jackson.html

Susan Anderson

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Re: Oceanic anoxia
« Reply #9 on: January 12, 2018, 09:17:30 PM »
@TerryM, apologies for not replying sooner, but I felt I had gone too far off topic already. This area is lovely, but the prognosis is not. Having the ocean come up to the sidewalk and alleys around us was not a recommendation. Yes, I'm a painter and work in a variety of media, ranging from plein air to semi-abstract. Colorful, energetic, weird. Do try a look at my icon, which comes from the studio.

idunno

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Re: Oceanic anoxia
« Reply #10 on: March 15, 2018, 10:26:34 PM »
From a comment on this article...

https://www.theguardian.com/environment/climate-consensus-97-per-cent/2018/mar/12/burning-coal-may-have-caused-earths-worst-mass-extinction

...which seems to me quite eloquent, if, hopefully, entirely inaccurate and unfactual...




There's another issue that this story forgot to mention, that's KINDA important to us today -

How the ocean lost its oxygen.

The oxygen in the ocean is produced by phytoplankton via photosythesis. Because they need sunlight, they hangs-out close to the surface where they can get that, and as a result, a good chunk of the oxygen they produce bubbles-up to the surface and out into the atmosphere.

In fact, about 2/3 of our planet's atmospheric oxygen is generated by these guys, with the remainder generated by terrestrial plants (which makes sense, when you realize that over 70% of the Earth's surface is covered by water).

Well, a few years ago, British scientists discovered that if the water gets too warm, phytoplankton photosynthesis SHUTS-DOWN.

No photosynthesis = NO OXYGEN produced.

With no oxygen, the fish suffocate and die.

Also, the source of 2/3's of the atmospheric oxygen levels you need to breath just got CUT-OFF, resulting in mass death of animals...and people!

But wait, it gets WORSE...

Lurking deep in the ocean, there's another player, anaerobic sulfur-reducing bacteria. These guys thrived billions of years ago, before the development of photosythesis. But they hate oxygen - it's poisonous to them - so when photosythesis took-off, they had to seek shelter in oxygen-free areas of the world. Like the sediment at the bottom of the world's oceans, where they survive eating dead organic material that settles to the bottom. The oxygen produced by the phytoplankton keeps them in check.

But with no oxygen in the ocean, they are now free to rise from the depths - and find a virtual smorgasbord of suffocated dead fish for them to eat! They quickly multiply, filling the ocean with their by-product - hydrogen sulfide, a poisonous gas - and killing-off anything else in the ocean that wasn't dead already.

Next thing you know, instead of oxygen bubbling-up from the world's oceans into the atmosphere, deadly poison gas is!

This stuff is pretty dangerous even at low levels - per CDC, extended (1hr) exposure >30 ppm can cause irreversible or serious heath issues, and 100 ppm is immediately dangerous to life or health (IDLH) -

https://www.atsdr.cdc.gov/mmg/mmg.asp?id=385&tid=67

http://www.alken-murray.com/H2SREM9.HTM

At sufficient concentrations, it is also toxic to plants - not only killing-off the base of the food chain - but also the other main source of atmospheric oxygen to breath!

During the Permian Extinction, massive volcanic eruptions helped all this along.

But you don't need a Super Volcano.

All you need to do to start this horrific chain of events - is warm-up the surface layer of the ocean just enough, that the phytoplankton decide to take a break.

That could happen as soon as the end of this century -

https://www2.le.ac.uk/offices/press/press-releases/2015/december/global-warming-disaster-could-suffocate-life-on-planet-earth-research-shows

SteveMDFP

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Re: Oceanic anoxia
« Reply #11 on: October 29, 2018, 02:00:53 AM »
Interesting article:

Coastal Pacific Oxygen Levels Now Plummet Once A Year
https://www.npr.org/sections/health-shots/2018/10/28/658476111/a-rural-community-decided-to-treat-its-opioid-problem-like-a-natural-disaster

"Deep Pacific waters 50 miles off the coast have always been hypoxic. And it's hardly surprising. The water down there take decades to slowly flow thousands of miles from Japan to the west coast — all the while separated from oxygen in the air.

But in 2002, fishers started to notice hypoxic waters moving closer-in — to just a couple of miles off the coast."

More interesting details at the link.

Sigmetnow

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Re: Oceanic anoxia
« Reply #12 on: October 29, 2018, 05:48:58 PM »
SteveMDFP, I believe the link below is the one you meant to post.  Indeed, it is shocking.

Coastal Pacific Oxygen Levels Now Plummet Once A Year
Quote
Scientists say West Coast waters now have a hypoxia season, or dead-zone season, just like the wildfire season.

Hypoxia is a condition in which the ocean water close to the seafloor has such low levels of dissolved oxygen that the organisms living down there die.

Crabber David Bailey, who skippers the Morningstar II, is rattled by the news. He remembers a hypoxia event out of Newport, Oregon, about a decade ago. He says it shows up "like a flip of a switch."

"It shows up like a flip of a switch," he says. "If there are crabs in the pot, they're dead. Straight up," Bailey says. And if you re-bait the pots, "when you go out the next time, they're blanks, they're absolutely empty. The crabs have left the area."

A hypoxia event will kill everything that can't swim away—animals like crabs, sea cucumbers and sea stars.

"We can now say that Oregon has a hypoxia season much like the wildfire season," says Francis Chan, co-chair of the California Hypoxia Science Task Force.  ...
https://www.npr.org/2018/10/28/658953894/coastal-pacific-oxygen-levels-now-plummet-once-a-year
People who say it cannot be done should not interrupt those who are doing it.

SteveMDFP

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Re: Oceanic anoxia
« Reply #13 on: October 29, 2018, 07:00:01 PM »
SteveMDFP, I believe the link below is the one you meant to post.  Indeed, it is shocking.

Coastal Pacific Oxygen Levels Now Plummet Once A Year
Quote
Scientists say West Coast waters now have a hypoxia season, or dead-zone season, just like the wildfire season.
. . .
https://www.npr.org/2018/10/28/658953894/coastal-pacific-oxygen-levels-now-plummet-once-a-year
Thanks for tracking down the correct link.  Haste makes waste.

I wonder about the suddenness of these events.  You'd think different animals would have different tolerance for hypoxia.  I suppose that once *some* animals die from hypoxia, the decomposing bodies consume more oxygen--a positive feedback effect.

gerontocrat

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Re: Oceanic anoxia
« Reply #14 on: October 29, 2018, 07:23:13 PM »
I wonder about the suddenness of these events.  You'd think different animals would have different tolerance for hypoxia.  I suppose that once *some* animals die from hypoxia, the decomposing bodies consume more oxygen--a positive feedback effect.

Indeed they do. But I think one should worry more about the potential loss of "photosynthetically active plants and bacteria in the ocean, the primary producers. Annually, they generate about the same amount of oxygen and fix as much carbon as all the land plants together. "
https://worldoceanreview.com/en/wor-1/ocean-chemistry/oxygen/
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Ktb

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Re: Oceanic anoxia
« Reply #15 on: October 30, 2018, 12:34:27 AM »
Edit: self moderated to another thread
« Last Edit: October 30, 2018, 01:41:45 AM by Ktb »