Sea ice is not a sterile environment

This morning I posted my 10,000 tweet.

Whilst I am not sure if 10,000 is significant, I pointed to the brilliant NASA Earth Observation www site which has a wonderful post today about the reduction of sea ice increasing phytoplankton growth in the Arctic. (Be sure to click the "image comparision" button on that page).

High chlorophyll in open water
Sat picture from 10 July 2011 showing milligrams of chlorophyll per cubic meter of seawater. From the Aqua Satellite

So ignore the fact that my tweet had the wrong year in (I said 2012, the pic is 2011 - the text on the page refers to date collected in 2012 hence the confusion). The point is the picture shows that in open water (the bit that isn't grey), in the Arctic there is increased light through the water column when you take the ice away. The result is the phytoplankton can grow to form relatively large blooms. Dr Karen Frey is quoted saying that in 2012 they measured:

a massive bloom of phytoplankton stretching up to 100 kilometers (60 miles) under the ice pack.

It struck me talking to people this morning that some people can think of the sea ice environment as a barren life free habitat. It's easy to think that when the images we have in our minds are of the "barren wastes".

But it is not like that all the time.

This is a unmodified picture I took of the sea ice in the Amundsen Sea, Antarctica.

Brown sea ice
A standard unenhanced picture of Antarctic sea ice. floe sizes ~1-2m across.

That incredible brown colouration is the pigment in micro-organisms which is absorbed into the sea ice when it is generated.  Sea ice is an amazing and complex habitat with organisms living in the gaps between the ice crystals. There is some great stuff online to tell you about the sea ice ecosystems, and the Alfred Wegener Institute have also made this interactive.

If you want to read an excellent introduction to the sea ice, its environment and impact, then Prof David Thomas wrote this wonderful book. Or there is the much higher level (and industrially expensive) book which I wrote a chapter for called just sea ice.

There is some top research in the UK going on about the biology of sea ice and the changing climate. For example Dr Ceri Lewis (Exeter) has some great stuff online here, and you can find Ceri on twitter.

6 thoughts on “Sea ice is not a sterile environment

  1. Alexander Harvey

    Hi Mark,

    I suspect it would be fair to consider the permanently covered polar waters as de facto marine and fishery reserves. I think that Proffesor Daniel Pauly has spoken to that end. The impossibility or trawling etc. has left them relatively untouched.

    That said, I do not think that those areas enjoy any official status as such.

    I think I do associated cold with marine abundance, but perhaps especially in association with upwelling, e.g. the Benguela Current with its pelagic fisheries. The natural tendency of wildlife film makers to concentrate on those parts of the tropics that have coral reefs ignores the large areas of warm oceans that I suspect are quite barren.

    Thanks for making me think about this.


  2. Post author

    Hello Alex, thanks for the comment.
    I dont know what Prof Pauly has said, but some work I did a few years ago suggested that in Antarctica, there is an increased density of krill just inside the ice edge. Krill being a food source for higher predators implies that we could expect more predaters.

    The science paper that we wrote is here:

    And maybe I will blog about that too.
    best wishes

    1. Mark Brandon

      Hi Katy,
      It just means that Krill swarms can be very large. Andorra is a small landlocked region of spain.
      I am guessing you are British? If so what it means is that a swarm of krill (we call it swarm but you would use shoal for fish), can be a third the area of London. Clearer?
      Thanks for you comment, Mark

      1. Yes it was clear, but just wrongly expressed. I thought everything originating from the UK had to be compared to the size of Wales. Perhaps I am watching the wrong stand up comedians....

        1. Mark Brandon

          You are probably watching the right ones. I think the issue is it was written by Germans. Different commedians...


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