The tropical
freshwater are known to exhibit less biodiversity as compared to more temperate
waters.The lack of such greater biodiversity in fresh water ecosystem is due to
several factors
These
factors are known to impede or limit the amount of biodiversity in fresh water.
The implicating factors are; all year round predation by the fish species in
such water bodies that graze continually on the planktonic communities in such
tropical freshwaters, temperature and salinity are also important factors that
limit zooplankton species diversity.
In
comparison to marine habitat, freshwater habitat are also much less biological
diverse. Marine habitat harbours much
more zooplankton communities than freshwaters. The observable differences are
very much likely to be due to great antiquity of the marine environment, depth of the water
body and evolutionary continuity found in the marine environments.
Even much
older lakes like lake Tangayika, are not biologically diverse when compared to
oceans. In the tropical freshwaters, planktonic animals are dominated by four
major groups which are:
·
Protists,
including protozoans and heterotrophic flagellates.
·
Rotifers
and other classes of crustaceans.
·
The
Cladocerans and
·
The
Copepods.
It is
noteworthy that protistan zooplankton are very important microbial consumers
and are functional in organic carbon utilization and nutrient recycling.
On the other
hand, flagellates are the most abundant component of the protozooplankton.
Whereas ciliates are largely holozoic and high feeding rate on bacteria, algae,
particulate detritus.
The
sarcodine protozoa only occasionally reach modest occurrence.
