Ventus by Karl Schroeder

Karl Schroeder / Ventus / Page 497
a scum of archaeobacteria in the slow oceans. But the air was
not breathable by human life, and it was too thin.
The planet was almost perfect. Very little needed to be
done except alter the atmosphere and provide a soil base. The
local life was not robust enough to survive what we were going
to do, but that was considered a good thing.
Upon agreement about the target, the Swans entered a
new phase of life. Each began transforming its local
environment into spaceships and nano-machines. The lesser
moons were eaten by the swans, and clouds of nano-machines,
the original mecha, moved to the other small worlds to eat
them too.
Meanwhile the swans moved in on this planet.
The fully-grown entities whom our designers referred to
as the "Winds" achieved orbit. They would coordinate
terraforming and manage the synthetic ecology of this world
from then on. They mapped the planet, dropped probes to
analyze the soil and microbes, and waited.
After several years, the first clouds of mecha from the
asteroids arrived. The clouds massed billions of tonnes, and
rained down for months, settling in the atmosphere. At the
same time giant solar mirrors slid into orbit to increase
insolation.
These mechal clouds drew power from the intensified
sunlight. With it they liberated oxygen from the air. The
carbon so produced weighed them down, and as they fell they
metamorphosed into new forms suitable for soil creation.
Since the air was very thin, the Swans had sent harvesters
to bring back oxygen from comets. This process was
underway but would take decades to bear fruit. Meanwhile we
turned our attention to the oceans.
While the dust on land continued to process and mutate,