Zooplankton Diversity in Tropical Freshwater

 

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.

Biomanipulation

Biomanipulation is a biological engineering in which manipulation of certain herbivorous organisms lead to the reduction of certain algal groups that are not wanted

It can also be said to be a biological process of elimination or reduction of the effect of eutrophication of a water body.

Biomanipulation is achieved when planktivorous fishes are reduced,which in turn leads to the increase in the density or number of Cladoceran zooplankton. And the grazing of these large Cladocerans on algal species in the water bodies in turn reduces their abundance. The reduction in the algal population, thus reduce the turbidity of the water caused by algal bloom.

To achieve biomanipulation, planktivorous fishes have to be reduced by several methods, among which are, the introduction of carnivorous fishes into the water body or by intensively harvesting planktivorous fishes found in the eutrophic water.

Importance of Biomanipulation

Biomanipulation is known to have several advantages where it is properly practiced.

·        It can reduce eutrophication in water bodies

·        It reduces turbidity caused by algal bloom

·        It removes species of algae that are known to produce toxic substances            (cyanotoxins)

·        It helps in reducing the eutrophication on other aquatic animals

·        It is an important alternative in the use of algicidal chemicals

Effective Biomanipulation

For biomanipulation to be effective, it has to be combined with other several methods.

Basically, reduction of nutrients getting into the affected water body has to be put in place; proper agricultural practices should also be put in place too. In addition to that, biomanipulation must be done consistently year in, year out before its benefits can be properly harnessed.