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Messages - longwalks1

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Arctic sea ice / Re: The 2019 melting season
« on: September 17, 2019, 09:28:59 PM »
One can see clearly on the Worldview that the new ice is forming on the nothern Greenland fjords and in the Nares strait. Some real (bottom) melting occur only in the Beaufort and Greenland seas. But in general the melting season is over and only compaction can decrease extent

Arctic sea ice / Re: The 2019 melting season
« on: August 31, 2019, 08:10:18 PM »
Losses will pick up a lot for this Time of year the next 10 days

Consequences / Re: Wildfires
« on: November 10, 2018, 04:24:42 PM »
I hardly know what to say about such horror and tragedy.

Permafrost / Re: Arctic Methane Release
« on: November 13, 2017, 02:14:58 PM »

ps:- Even if emissions are slow enough to allow decomposition in the water column, my understanding is this will be through aerobic decomposition by bacteria producing CO2 (acidification) and oxygen depletion possibly on a sufficient scale to result in wide-scale dead zones in the ocean and destruction of marine life. Any evidence anywhere?

That's basically what happens when productivity in an area is suddenly increased: increased draw-down of carbon, followed by benthic oxygen depletion. Added to that is a slow-down in thermohaline circulation due to the global temperature rise, which just makes any potential worse, and this is why the warmest periods of the Phanerozoic (e.g. Middle Ordovician and Cretaceous) are characterised by a lot of black mudstones with no benthic fossils.

My PhD was on the effects of volcanic ash-fall on Ordovician ecosystems, where the nutrient supply was from upwelling due to hyperpicnal surface waters laden with fine ash, which promptly sank on mass. (The same thing was seen after Pinatubo - a Steve Sparks paper, iirc). The result there was a mass bloom of plankton, followed by benthos, followed by a swift return to anoxia, and, as it happens, lots of exceptional fossil preservation through rapid replacement by pyrite (iron sulphide). And this was only dealing with a local scale, with lateral mixing ameliorating the effects significantly. This process is one of many reasons why CO2 capture by ocean fertilisation was such a spectacularly catastrophic idea; luckily the fish-farming element failed, so it seems to have been largely dropped.

Apologies for lack of reference - I'm currently in a small town in southern China, on fieldwork, and a long way from the literature I was using at the time!

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