Stephen
It was an excellent segment on Catalyst. Almost spookily timely.
Carl Clifford
On 15/04/2011, at 9:52 AM, Stephen Ambrose wrote:
Hi All,
I’m just forwarding a comment from Tim Reid about krill and whale
numbers (see below). Tim is an Australian scientist who is currently
working in South Africa and is not currently subscribed to Birding-
aus. Some of you may know Tim for the seabird research he has
conducted over many years, particularly in Tasmanian waters.
Coincidentally, the same story was on Catalyst on ABC TV last night.
The link to this story is shown below:
Iron Whales: http://www.abc.net.au/catalyst/
The gist of the story is that phytoplankton on the ocean surface take
up carbon dioxide from the atmosphere, but need iron to do this.
However, there is a shortage of iron on the surface of the Southern
Ocean. Individual phytoplankton gradually sink to the lower depths of
the ocean, krill feed on them and bring the iron that was stored in
the phytoplankton back to the ocean surface. Baleen whales feed on the
krill. Therefore, iron is concentrated further up the food chain, i.e.
phytoplankton to krill to whales. The whales in turn poo out a lot of
the iron which is returned to the ocean surface. The next stage of the
research is to establish whether or not the phytoplankton can utilise
the iron that is pooed out by the whales.
So contrary to claims on Birdng-aus yesterday, more whales potentially
means more phytoplankton, which potentially means more (not less)
krill. More phytoplankton also means that more carbon dioxide can be
absorbed from the atmosphere, which could in turn slow down global
warming. I can’t remember the exact figure, but I think the Catalyst
story said that ocean phytoplankton is responsible for about one
quarter of all atmospheric carbon dioxide taken up by the earth’s
vegetation. But don’t quote me on that figure, I’d have to look at the
story again.
Regards,
Stephen Ambrose
Ryde NSW
On Thu 14/04/11 9:58 PM , "Timothy Reid" <> wrote:
Hi Stephen,
I'm not on Birding-Aus (don't want to fill my inbox), but do read the
archives.
A paper of interest with regards krill numbers in the antarctic is
linked below.
Basically suggests that krill numbers are low these days because whale
numbers are low, with their poo fertilising the sea (think of some of
the ideas to overcome climate change by adding iron to the sea). Whale
poo is high in iron and where likely to fertilise the oceans, krill is
also high in iron and so needs there being a lot there.
Not that I should be thinking about such things (I'm living in Cape
Town at the moment).
Hope you’re well!
tim.
http://onlinelibrary.wiley.com/doi/10.1111/j.1467-2979.2010.00356.x/pdf
------------
Dr Tim Reid
Percy FitzPatrick Institute of African Ornithology
DST/NRF Centre of Excellence
Private Bag X3
University of Cape Town
Rondebosch 7701
Cape Town, South Africa
Web site: <http://www.fitzpatrick.uct.ac.za/> http://www.fitzpatrick.uct.ac.za/
Phone: (+27) (0) 21 650 3619
Fax: (+27) (0) 21 650 3295
Cell: (+27) (0) 83 3991 9165
Mail 1:
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Mail 2: <javascript:>
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