In article ,
Peter Jason wrote:
All the publicity about the "wicked CO2" levels in the atmosphere may be
redundant if most photosynthesis occures in the oceans, because as the CO2
level increases then so should the phytoplankton levels to compensate for
it. The "lungs' of the earth then are not the Amazon and other forests but
the oceans of the world. Also, the large quantities of CO2 will be locked
up by sea ceatures as carbonate.

CO2 levels are increasing faster than the oceans can take the surplus
up, i.e. equilibrium hasn't been reached, and the disequilibrium is
getting worse. The CO2 in the atmosphere is causing global warming,
which will increase CO2 levels in a positive feedback cycle, as shifting
patterns of rainfall make forests less viable, promote forest fires,
and dry out arctic muskeg exposing thick layers of ancient peat to
rapid oxidation.

Note that CO2 taken up by land plants may be locked up in cellulose for
millennia, while CO2 taken up by algae is mostly released soon after as
the algal cell metabolizes and when it dies.

The oceans are full of carbonate, so it's unlikely that CO2 level is a
limiting factor in phytoplankton growth, as it is in land and fresh
water plants under some conditions. Most likely, the limiting factor
is light or nitrate in the most productive parts of the ocean.

As for the shelly fauna of the sea taking up the excess carbonate,
carbonate is not a limiting factor in the growth of marine fauna,
either. Note also, that most calcium carbonate is recycled in the
oceans -- shells are consumed by other organisms and any that fall
below a certain depth dissolve at the higher pressures. Very little
sticks around long enough to become limestone.

There have been times in the past that planetary equilibria with higher
levels of atmospheric CO2 have been maintained, but they were
associated with different climates than we have now as well as
completely different flora and fauna. So sure, a new equilibrium can
be attained, but it may well not be one that can support 6 billion
humans, and it may involve extreme fluctuations in climate and
biosphere on the way which could take millions of years to recover
from. Even fairly minor fluctuations can result in massive human
death tolls, mostly from starvation as crops fail and the best
agricultural land is destroyed by rising sea levels.

So yeah, if you're concerned about the Future of Life on Earth, don't
worry, take the long view, even the catastrophic extinctions returned
to comparable biodiversity in 25-50 million years. Not the same
animals and plants, but plenty of them. But if you're concerned about
yourself and the next few generations, there's no reason to believe
it's business as usual, the oceans will sop it all up, let the good
times roll.