The reality of life is that Life is opportunistic. Living things will do
whatever they can do, go wherever they can get to. I think there is a
theoretical law pertaining to the distribution of freshwater fishes that
was coined by an icthyologist in the late 19th Century. It postulates
that fish will get into just about every system they can- limited only
by the conectivity of watersheds , climate and a few other factors.
There is another theory- remember Gia - the idea of Earth's biosphere as
a single, self-regulating superorganism? Well, an article appeared in
Discover several years ago advancing a newer concept called "Hypersea".
It seems a more accurate representation of ecology than Gia because it
asserts that the planet is divided into many separate systems or
'reservoirs'. This is especially true of aquatic systems. Organisms that
find their way into new reservoirs often cause trouble for reasons that
most everyone on this list is familair with. It's alot like the case of
pathogens like HIV that cross over into new species - from monkeys to
us! Pathogens and parasites tend to evolve into more benign forms that
peacefully co-exist with a new host pool ultimately becoming symbionts.
Likewise for larger life forms which eventually settle into a vacant
niche or push something else out and take possession of theirs.
The article was ideologically neutral though it did say we should
manipulate the currents of Hypersea with caution.
Perhaps the most interesting part of the article was the speculative
vision of where Life might go in the future. In the past life in the sea
was dominant and held most of the biosphere's life sustaining nutrients.
But land based life captured alot of that stuff and now holds onto it at
the expense of life in the sea- so the theory goes. The deep tropical
oceans are mainly the marine equivalent of deserts- except where you
have upwellings of nutrient rich water from deep down where most
nutrients in the oceans get locked up.
The author went on to suggest that mangrove trees might be a promising
candidate for taking Hypersea back out to sea by evolving some kind of
floats and then drop deep roots into the stygean depths. The mangroves
would be aided by a host of symbionts - sponges, bryzoans, anemones,
mollusks etc that would tap those deep ocean reserves and blanket the
oceans for thousands of miles. This would also pump copious amounts of
oxygen into the atmosphere which could have dire consequences for land
life.
Raising the oxygen levels of the atmosphere even a few more percentage
points would increase the combustability of everything. The author said
- hit a tree with a ball bat and it bursts into flame! Sounds a lot like
a world breifly mentioned in Gregory Benford's "Across the Sea of Suns"!
I don't know about that one- the mangroves would supposably be safe
because they are in water but would probably be self limiting by the
reduced greenhouse effect that would make more areas of the planet less
suited for them.
Jeff
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