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The World on a
7
Tiny Scale
The alga Volvox. Image: Stephen Durr
Lots of types of algae live in this kind of a pond.
The alga Spirogyra with spiral-shaped chloroplasts
microscopic world of predators and prey inside
a water droplet.
The unbelievable variety of animals and plants that you can
find in water makes it difficult to give just a quick overview.
Even seasoned biologists have difficulty identifying every
organism under the microscope by name. It is the microscope
experts who often best know their way around in this world.
With your microscope, you can study a wide variety of habi-
tats and perhaps become an expert yourself. Here are a few
tips and tricks on how and where you can find worthwhile
specimens from watery habitats, and how to prepare them
for viewing.
Searching and Finding
Looking at tap water isn't worth the trouble. Our drinking water is subject to strict
cleanliness guidelines and is therefore mostly germ- and microbe-free. The obser-
vations begin to get interesting when you are looking at waters that don't exactly
entice one to bathe in them: ponds and puddles with green alga growth offer a
true paradise for interesting creatures to investigate.
You can take samples from the water in a number of different ways. Just like in
the human world, the inhabitants of lakes and ponds have a wide variety of life-
styles and can be found in very different places. Many algae float freely in water in
order to get as close to the light as possible. Water fleas rudder through the water
with their antennae and use their legs to filter out small algae and animals.
A limnologist, which is someone who studies inland waters like lakes, ponds, and
rivers, would fish out these animals and plants with a very fine net (a plankton
net). But you can also catch them by simply taking a water sample using an empty
jelly jar. Some animals can already be seen with the naked eye. These "microscopic
giants" can best be observed with the special slide with the concave trough. The
problem of catching too few of these tiny creatures and consequently having to
search for a long time with the microscope can be solved with a so-called hay infu-
sion (see page 24).
24
Up to now, you've used your micro-
scope to look at small sections of
large organisms. But there is another,
otherwise invisible world for you to
discover. Invisible to the naked eye,
a colorful and fascinating variety of
microscopic plants and animals can be
found in water barrels, flower vases,
and ponds. Green plants, mostly al-
gae, with uniquely shaped chloroplasts
make up many animals' diets. Extremely
tiny crabs or cnidarians, in turn, have a go
at the plant eaters. You can find an entire
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