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Jun 11 2012

Blooms beneath the ice

Cryo-researchers have found algal blooms below the polar ice that are far more robust than once thought, and that could explain some things:

(CNN) — Researchers were amazed to discover a colossal 100 kilometer (62 miles) stretch of phytoplankton blooming under Arctic ice, north of Alaska, in July last year.

It had previously been assumed that sea ice blocked the sunlight necessary for the growth of marine plants. But four times more phytoplankton was found under the ice than in ice-free waters nearby.

Scientists now believe that pools of melting ice actually function like skylights and magnifying glasses, focusing sunlight into sea water, providing the perfect conditions for the intense phytoplankton bloom, which makes the water look like pea soup.

That might also help explain how life survived and thrived during the snowball earth phase hundreds of millions of years ago, when most or all of the planet was covered by ice.

6 comments

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  1. 1
    Gregory in Seattle

    It would explain how life survived, but this is bad. Water only looks dark, while algae IS dark: it will hold heat, while metabolic process actually generate heat. The result is that the melt of the Arctic ice cap is going to occur faster than predicted, because the ice is being heated at the bottom as well as at the top.

  2. 2
    lochaber

    maybe this can help sequester some carbon? although, if so, it’s probably just part of the unaccounted carbon sinks.

    I really hope that there is enough of this that it can slow things down a bit, but I’m pessimistic enough to realize that we will still worry more about our short term economy and profits then mid-long term survival.

    :(

  3. 3
    StevoR : Free West Papua, free Tibet, let the Chagossians return!

    @ ^ Gregory : Water only *looks* dark? That’s not my understanding of it!

    I’m pretty sure I;ve seen the figure in a few places – most memorably in Greenman 3610′s Climate Denial Crockof the Week youtrube series – that open ocean absorbs 80% of incoming sunlight versus ice reflecting 80% of it.

    One possibly good aspect is that the extra plankton blooms here mayactaa stabilising feedback and carbon sink absorbing some of the carbon dioxide from the atmosphere although I’m unsure ecxactly howmuch or to what extent that willcancel out the shifting albedo effect.

    Anyone know more and care to enlighten us all?

  4. 4
    Alex

    IANAW (I am not a waterologist), but my take on it is: The ocean as a whole is not that reflective (it does not appear like plain white, nor particularly bright), which means that a large amount of sunlight which enters it gets absorbed somewhere. Since it is basically dark at great depths, the missing light, i.e. basically all of it, was absorbed by the water and converted into heat. My suspicion is therefore that the albedo of “no ice” versus “no ice + algae” will not be radically different. Without algae, the light will penetrate deeper into the water, but it will perish nonetheless.

    I don’t know whether algae will act as an efficient carbon dioxide sink. Sure, the might start to grow if they get more light, but once they reach a certain equilibrium, the dying plants will rot and put the co2 back into the atmosphere. One would have to harvest them and put them into old coal mines (this is actually being contemplated with other types of plants in order to have solar powered biological co2 storage.)

  5. 5
    Alex

    > the dying plants will rot and put the co2 back into the atmosphere.

    Or even worse, CH4

  6. 6
    StevoR : Free West Papua, free Tibet, let the Chagossians return!

    I’m pretty sure I’ve seen the figure in a few places – most memorably in Greenman 3610′s ‘Climate Denial Crock of the Week’ youtube series – that open ocean absorbs 80% of incoming sunlight versus ice reflecting 80% of it.

    Of course, I can’t seem to find that exact figure in any of the sources I thought they were in, now.

    But via the National Snow & Ice Data centre :

    http://nsidc.org/cryosphere/seaice/processes/albedo.html

    Sea ice has a much higher albedo compared to other earth surfaces, such as the surrounding ocean. A typical ocean albedo is approximately 0.06, while bare sea ice varies from approximately 0.5 to 0.7. This means that the ocean reflects only 6 percent of the incoming solar radiation and absorbs the rest, while sea ice reflects 50 to 70 percent of the incoming energy. The sea ice absorbs less solar energy and keeps the surface cooler.

    Snow has an even higher albedo than sea ice, and so thick sea ice covered with snow reflects as much as 90 percent of the incoming solar radiation.

    Sorry about the typos. Hope y’all get the gist anyhow.

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