Page 40 - Engineering in Nature

Engineering in Nature

AN IMPORTANT SOURCE: DIATOMS
Diatoms are microscopic plant algae. Up to 10,000 of these living
things, the largest of which is only 1 mm in diameter, can be found in
1 cubic centimeter of sea water. Not all diatoms live in water, howe-
ver. Some live in soil, on the moss clinging to trees, and even on walls
where there is sufficient moisture. These golden yellowy-brown algae
can be found wherever there is light, heat, water, carbon dioxide and
sufficient nutriments.
In a sense, land-dwelling creatures, including humans, owe their
lives to diatoms. A large percentage of the oxygen we breathe is pro-
duced by diatoms, via photosynthesis. On diatoms, a large number of
pores allow nutriments to enter and also allow exchange of gases.
Diatoms work like micro-factories to produce oxygen. At the end of
these gas exchanges, trillions of diatoms produce more oxygen than
they need and make a vital contribution to the levels of oxygen in the
atmosphere.

They also play a most important role in the marine food chain,
since diatoms are the basic food source for the tiny creatures that con-
stitute animal plankton. These, in turn, serve as food for larger ani-
mals, such as herring. Such enormous creatures as the humpbacked
whale feed on nothing but diatoms. It takes a meal of hundreds of bil-
lions of diatoms to satisfy a humpbacked whale for only a few hours.
Diatoms' most impressive characteristic is the shells they build for
themselves. Flawless architects, they make themselves homes out of
opal (organic glass) in the sea. Some of these structures resemble a
shining pine cone or a spiral, or a glittering chandelier. Interestingly,
although there are more than 25,000 different species of diatom, their
shells are all different. Just as with snowflakes, every single diatom
species has a different appearance.

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