From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Sun Jan 05 2003 - 09:08:37 MST
It is interesting how somedays one wakes up and a totally
unrelated thought relative to what you have recently been
thinking about pops into your head.
This morning I realized that the decimation of the large
population of baleen whales (e.g. gray, blue, humpback and
right) in the late 1800's and early 1900's may have played
a role in the process of global warming. Reasoning: Baleen whales
feed on very small fish and crustaceans such as krill. These
in turn feed on zooplankton which in turn feed on cyanobacteria.
By eliminating the predators at the top of the food pyramid,
one allows an expansion of the numbers next lower level (e.g.
the krill). These will reduce the population of zooplankton
which in turn should allow an expansion of the cyanobacteria
population. Since the cyanobacteria are the primary fixers of CO2,
the result "should" be to decrease atmospheric CO2 and therefore
lessen global warming. Now as some know, cyanobacteria are
nutrient limited by iron in parts of the Pacific and Phosphorous
in parts of the Atlantic, but eliminating their consumption by
zooplankton which respire the CO2 back into the ocean and thence
the atmosphere should have some positive effect.
If this reasoning is correct, allowing the baleen whale population
to recover, reducing the population of their direct food sources
should allow an expansion of zooplankton, a reduction in cyanobacteria
numbers and a reduced capacity of the oceans to fix CO2.
The law of unintended consequences strikes again. Fortunately,
the generation time for whales is long so we may not have to
deal with the problem before we have alternate means available
to "set" the atmospheric CO2 level.
Robert
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