Page 54 - The Microworld Miracle

These bacteria are very small in size, but their numbers are very
great. There are more than 100 in a liter of water, and they represent
10% to 20% of the productivity of the oceans. Despite being too
small to see, they exist over a large part of the world. Their enor-
mous numbers are of the very greatest importance due to the ener-

gy they produce with photosynthesis.
The particularly complex and delicate mechanism of photo-
synthesis is is not yet fully understood. Also, the process is one of
the best examples of irreducible complexity. In other words, in or-

der for photosynthesis to take place, a great many special structures
have to be present at the same time and work together in a coordi-

a b

c

THE MICROWORLD MIRACLE The pictures show three types of cyanobacteria. (a: Nostoc, b: Oscillatoria, and c:

Gleocapsa). These bacteria, which live in clean waters, have exceptionally com-
plex chlorophyll. Thanks to these systems, which are almost as complex as plant
chloroplasts, cyanobacteria perform the process of photosynthesis in nature.
Nostoc cyanobacteria also play an important role in nitrogen transformation and
52 the "fixing"of atmospheric nitrogen.