Geology Reference
In-Depth Information
In the real world, the cloud-seeding algae are retreating further and further polewards
as human emissions of greenhouse gases warm the oceans. Perhaps the Lovelock and
Kump model, for all its simplicity, captures something essential about the real-world cli-
mate system, for the flip to the new hot state happens when carbon dioxide in the air
reaches 500 ppm—a conclusion also suggested by the latest generation of complex cli-
mate models.
It could also be that peat bogs on land and algae in the ocean work together to keep
Gaia cool. The American scientist Lee Klinger has observed that DMS emissions from
marine algae are highest in waters near coasts and islands. You would be right in think-
ing that this could be because nutrientrich agricultural runoff, finding its way into the sea
via rivers, gives the algae the nourishment denied them in summer time by the warm lid
of water that develops on the ocean surface. This is exactly what happens in the heavily
polluted waters off the coasts of northern Europe, but the effect also happens in places
far away from agricultural contamination, such as in the Arabian sea, where algae thrive
all year round despite strong seasonality in nutrient-rich upwellings. Klinger suggests
that in the absence of upwellings, algae thrive best in coastal areas that receive river wa-
ter from nearby peat bogs. As evidence, he cites the fact that massive plankton blooms
in the St Lawrence estuary in north-eastern Canada tend to happen when great surges of
fresh water from rivers which drain peat bogs reach the sea. Clearly, there is something
in the river water that the algae like.
The magic ingredient seems to be iron, which is scarce enough in the ocean to limit
algal growth. Peat bogs consist of one major kind of plant— moss—most often only one
kind: sphagnum. Mosses are happy in the wet and damp, and in order to keep things
moist they release sulphur gases to the air which seed clouds and trigger rainfall. Like
the rainforests, peat bogs maintain their own water cycle, and can kill large areas of
forest by making things so rainy that the trees die of root drowning. Peat builds up when
mosses on the surface of the bog die and are covered by new growth. The dead and dy-
ing moss releases humic and fulvic acids which inhibit decomposing bacteria so effect-
ively that great masses of spongy black peat build up, which impede drainage, helping
to kill trees and shrubs with the high soil moisture content. These peaty acids are adept
at extracting heavy metals such as iron from the bedrock below the peat. The metals are
chelated
by these acids, and as those of us who take vitamin supplements know well
enough, this means that the acid surrounds the metal in a protective chemical embrace
which makes it much more easily absorbed across the cell membranes of living beings.
Rivers draining peat bogs carry from two to ten times the average amount of iron, which
reaches the algae in the ocean in easily digested, chelated packages.
The marine algae thrive on the peat bog's gift of iron, producing vast amounts of
DMS just off the coast, not far from the peat bogs. The DMS (and other sulphur-bear-
