Contender 1: "Farm the Ocean" and capture CO2 in the process
Huge water-borne farms can turn the tide
against increasing greenhouse gases
The TimesMay 14, 2005
The team envisages 100 vast nets
full of quick-growing seaweed,
each measuring six miles by six miles,
floating off the northeast coast of Japan.
The seaweed in each net, growing to a weight
of 270,000 tonnes a year, will absorb
prodigious quantities of greenhouse gases and
convert them to oxygen before being harvested
12 months later as a rich source of biomass energy.
The Japanese Ministry of Economy, Trade and Industry
mentioned carbon dioxide absorption by seaweed
in its Technology Roadmap for 2005.
The project is led by Masahiro Notoya,
a world expert on seaweed from the Tokyo University
of Marine Science and Technology.
Dr Notoya believes that Sostera marina and sargassum,
herded to the right parts of the ocean, will grow
up to 40ft every year, absorbing about 36 tonnes
of carbon dioxide in the process. Those seaweeds
are also popular fare for a variety of fish
whose stocks have dwindled.
Working with Dr Notoya are scientists at
the Mitsubishi Research Institute and Tokyo University.
Mitsubishi Heavy Industries, Mitsubishi Electronics,
Toshiba and NEC are among a large group of companies involved.
The Japanese Government has provided a small grant
and is expected to give more when a pilot version
of the giant seaweed farm opens next year.
Tokyo University Research, Tokyo, Japan
Well people have suggested to reduce the carbon dioxide
in the atmosphere that plants, those synthetic organisms
are suitable sinks because that's the only group that
really fixes that carbon dioxide and
people are doing tree farming and so on.
However, the seaweeds or the algae and in particularly
the microscopic plankton can fix a lot more carbon than a forest can.
And then they also have the advantage that the marine ones
of course live on sea water. Forests on the other hand
need fresh water, they need land that we might need
for agriculture and other areas as well,
so there's a real competition here.
So we've been looking at using planktonic algae,
micro algae, marine algae as ways of fixing carbon dioxide.
However, there's an additional problem,
you can fix the carbon dioxide and you can get very high rates,
ten times per area or more than a forest does.
But the algae once they die, break down very quickly
and release the carbon dioxide again.
However there's a group of marine algae that makes
small plates of limestone or calcium carbonate
so about half the carbon that they take up goes into the cell
and the other half goes into these limestone plates.
We need a lot but remember if we can grow them intensively
we can get per square metre of land surface area,
in this case ponds I guess, about 100 times as much carbon fixed
as the same area of forest and we're using sea water
Murdoch University Research, Perth, Western Australia