So these and other environmental concerns about
ocean fertilization triggered a symposium in 1991 where a group
of oceanographers and limnologists gathered to talk about the evidence
for iron limitation of the oceans and the potential and risks of
using this knowledge for to try to regulate climate. The results
of that symposium were published in a special issue of the journal
of Limnology and Oceanography, and it culminated in this resolution:
"That iron fertilization is a scientifically uncertain mitigation
measure to reduce rising CO2 levels.
It would likely, at best, postpone the impending climate change
by a few years." This statement was based on computer modeling
efforts in which the entire Southern Ocean was fertilized with iron
for 100 years, such that all of the available N and P were used
up and converted to organic carbon. The group concluded, therefore,
that "Ocean fertilization should not be considered as a policy
option that significantly changes the need to reduce CO2
So that was the resolution back in 1991. The other outcome from
that symposium was generate interest in the iron hypothesis. It
became clear that doing some very small-scale fertilization experiments
in the ocean would be very useful in helping us understand not only
what regulates productivity in ocean ecosystems, but also the changes
in climate during glacial/interglacial transitions.
such experiments have been done, unequivocally proving that iron
does limit productivity in the Equatorial Pacific and the Southern
Ocean. Kenneth Coale will describe the results of those experiments,
and Dave Karl will then discuss the biological details and all of
the uncertainties involved in the 'biological pump'.
The experiments have proven that this is a powerful new approach
to oceanography, which for the first time allows us to manipulate
the food web so we can better understand how it works. They have
also shown us how very small amounts of a nutrient can trigger major
changes in the ocean ecosystem. Finally, they have catalyzed interest
in ocean fertilization as a carbon sequestration tool.
are many reasons to worry about what this type of technology might
do, not only to the marine ecosystem, but also to other regulating
mechanisms in the climate system.