Ecological Classification of Fresh water

Organisms in Fresh water (or any other natural habitat) are not arranged in taxonomic order (such as is followed in taxonomic text or systematic museum) some sort of classification on an ecological basis is useful

Autotrophs (producers)

are green plants and chemosynthetic microorganism.

Phagotrophs (Macroconsumer)

primary, secondary, etc, herbivores, predators, parasites

Saprotrophs (microconsumer or decomposers)

Subclassified according to nature of the organic substrate decomposed

Organisn in water may be classified as to their life form or life habitat, base on their

mode of life.

Benthos

Organism attached or resting on the bottom or living in the bottom sediments

Periphyton or Aufwuchs

Organisms (both plant and animal) attached or clinging to stems

Plankton Floating organisms whose movements are more or less dependent on current. While some of the zooplankton exhibit active swimming movements that aid in the maintaining vertical position plankton as a whole is unable to move againts appreciable currents.

Nekton

Swimming organisms that able to navigate at will(and hence capable of avoiding plankton, nets, water bottles etc.) Fish amphibians, large swimming insects and so fourth.

Neuston

Organism resting or swimming on the surface.

Finally, organism may be classified as to region or

subhabitat. In the ponds and lakes three zones are generally

evident

Littoral Zone The shallow water region with light penetration to the bottom typically occupied by rooted plants in natural ponds and lakes but not necessarily.

Limnetic Zone

The open water zone to the depht of effective light penatration, called the compensation level which is the depth at which photosynthesis just balances respiration.

Profundal Zone

The bottom and deep water area which is beyond the depth of effective light penetration. This zone is often absent in ponds.

Rapid Zone

Shallow water where velocity of current is great enough to keep the bottom clear of silt and other loose materials, thus providing a firm substrate.

Pool Zone

Deeper water where velocity of current is reduced and silt and other loose materials o be tend to settle to the bottom, thus provide a soft bottom.

The Fresh Water Biota The major Divisions of plants and many of the major animal phyla are represented by one or more genera living in fresh water communities.

LENTIC COMMUNITIES The biological characteristics of still water bodies.NATURE AND COMMUNITIES IN THE LITTORAL ZONE Producers Consumers

The Limnetic Zone

The limnetic zone is the well it, open surface waters in a lake, away from the shore. The vegetation of the littoral zone surrounds this expance of open water and its above the profundal zone.

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