ABSTRACT
As already pointed out in the previous chapters, algae grow in almost every habitat in every part of
the world. They can be found on very different natural substrates, from animals (snails, crabs,
sloths, and turtles are algal hosts) to plants (tree trunks, branches and leaves, water plants, and
macroalgae), from springs and rivers to hypersaline lagoons and salt lakes. They also colonize
artificial habitats, such as dams and reservoirs, fountains and pools, but cans, bottles, plant pots,
or dishes allow algae to extend their natural range. The ubiquity of these organisms together
with the plasticity of their metabolic requirements make many algal species easily available for
investigation, collection, or simple observation.
