I believe this is well authenticated. I read a New Scientist feature on
the topic maybe a year ago. The main thrust was that this maintains the
populations of fish and other marine life. With the huge reductions in
whale populations the oceans as a whole have become less productive -
and fish catches have declined not only as a result of over-fishing. It
turns out that Greenpeace did well to choose the whales as their iconic
life form as they are "keystone species" in the functioning of global
marine ecosystems. Oliver.
On 19/08/2013 21:34, Greg Rau wrote:
If whales increase the ocean carbon sink (and I've got to read the
fine print to be convinced), then the obvious geoengineering response
is to breed more whales. And/or will whale harvesters now need to pay
a carbon tax? Could partnering with ETC and Greenpeace on this be far
behind?
Greg
------------------------------------------------------------------------
*From:* Fred Zimmerman <[email protected]>
*To:* geoengineering <[email protected]>
*Sent:* Monday, August 19, 2013 9:49 AM
*Subject:* [geo] sperm whales and oif
*Reference: *Proc Roy SocBhttp://dx.doi.org/10.1098/rspb.2010.0863
Sperm whale poo offsets carbon by fertilising the oceans with
iron
<http://blogs.discovermagazine.com/notrocketscience/2010/06/16/sperm-whale-poo-offsets-carbon-by-fertilising-the-oceans-with-iron/>
By Ed Yong <http://discovermagazine.com/authors?name=Ed+Yong> |
June 16, 2010 8:00 am
Sperm_whales
<http://blogs.discovermagazine.com/notrocketscience/files/2010/06/Sperm_whales.jpg>
While the world wrangles over ways of reducing carbon emissions,
some scientists are considering more radical approaches to
mitigating the effects of climate change. Dumping iron dust into
the world’s oceans is one such strategy. Theoretically, the iron
should act as fertiliser
<http://en.wikipedia.org/wiki/Iron_fertilization>, providing a key
nutrient that will spur the growth of photosynthetic plankton.
These creatures act as carbon dioxide pumps, removing the
problematic gas from the air and storing the carbon within their
own tissues. When the plankton die, they sink, trapping their
carbon in the abyss for thousands of years.
It may seem like a fanciful idea, but as with much of our
technology, nature beat us to it long ago. Trish Lavery from
Flinders University has found that sperm whales fertilise the
Southern Ocean in exactly this way, using their own faeces. Their
dung is loaded with iron and it stimulates the growth of plankton
just as well as iron dust does.
Sperm whales <http://en.wikipedia.org/wiki/Sperm_whale> are
prodigious divers, descending to great depths in search of prey
like squid. When they’re deeply submerged, they shut down all
their non-essential bodily functions. Excretion is one of these
and the whales only ever defecate when they reach the surface. By
happy coincidence, that’s where photosynthetic plankton
(phytoplankton) make their home – in the shallow column of water
where sunlight still penetrates. So by eating iron-rich prey at
great depths and expelling the remains in the shallows, the whales
act as giant farmers, unwittingly seeding the surface waters with
fertiliser.
There are approximately 12,000 sperm whales left in the Southern
Ocean. By modelling the amount of food they eat, the iron content
of that food, and how much iron they expel in their faeces, Lavery
calculated that these whales excrete around 50 tonnes of iron into
the ocean every year. And based on the results of our own iron
fertilisation experiments, the duo calculated that every year,
this amount of iron traps over 400,000 tonnes of carbon in the
depths, within the bodies of sinking plankton.
Previously, scientists assumed that whales (and their carbon
dioxide-rich exhalations) would actually weaken the Southern
Ocean’s ability to act as a CO2 pump. But according to Lavery,
this isn’t true. She worked out that the whales pump out just
160,000 tonnes of carbon through their various orifices. All of
these figures are probably conservative underestimates but even
so, they suggest that sperm whales remove around 240,000 more
tonnes of carbon from the atmosphere than they add back in. They
are giant, blubbery carbon sinks.
However, their true potential will go largely unfulfilled thanks
to our harpoons. Many sperm whales have been killed by industrial
whalers, and the population in the Southern Ocean has declined by
some 90%. On the bright side, the Southern Ocean’s population
represent just 3% of the global total, so this species may have an
even greater role as a warden for carbon than Lavery has
suggested. Other seagoing mammals probably have a part to play
too, provided that they feed at depth and excrete near the
surface. Several other toothed whales do this, and some
filter-feeding ones may do too.
*Reference: *Proc Roy Soc B http://dx.doi.org/10.1098/rspb.2010.0863
*Image *by Cianc
<http://www.flickr.com/photos/cianc/298211739/in/photostream/>
---
Fred Zimmerman
Geoengineering IT!
Bringing together the worlds of geoengineering and information
technology
GE NewsFilter: http://geoengineeringIT.net:8080
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