Benthos, Freshwater Fishes, Macrophytes, Microbiology of The Fresh Water

Benthos

Benthos are the organism attached to some substratum or resting on the bottom or living in the bottom sediments. There are both plant benthos as well as the animal benthos in the fresh water. The plant benthos i.e phytobenthos constitutes the rooted plants belonging mostly to the division spermatophyte i.e seed plants are found in the littoral zone. The animal benthos may be conveniently subdivided into the filter feeders such as the clams and the deposits feeders such as snails. Zoobenthos i.e animal benthos are abundantly found in the littoral zone are crayfish, isopods, certain mayfly nymphs. The benthos found in the rapid zone show the adaptation for the maintaining position in the swift water. The plant benthos in the rapid such as the Cladophora encrusting the diatoms, aquatic mosses of the genus Fontalis remain permanently attached to a firm substrate, Simulium, and the Blepharocera enables them to grip even seemingly smooth surface. The presence of the sticky under surfaces in snails and the flatworms able them to adhere to the surface. The other adaptational features shown by his organism in the rapid are streamlined and the flattened bodies, positive phototaxis, and the positive thigmotaxis.

Freshwater fishes

Fishes in the fresh water are dominated by the bony fishes such as perch, trout or minnows. Most of the fish possess gas bladder which allows them to maintain almost neutral buoyancy in the water column. Many fishes live and breed in one area but a few migrate considerable distances. Fishes are usually the largest animals and influence the structure of the aquatic ecosystem by their various predations.

Planktivorous fish usually feed on the zooplanktons but sometimes utilize Phytoplanktons. Fishes such as the sheds, herring or the minnow feed on the zooplankton for the most of their lives. Almost all fish even the large predators like pike and the lake front feed on the tiny rotifers, protozoans, and other small planktons during their early development.

Water quality remains of the prime importance for the fishes. One of the most serious effects of the eutrophication in the lakes is its effect on the depletion of oxygen in the hypolimnion. Fish kills may also result from the excessive eutrophication were bacteria and the plant respiration depletes dissolved oxygen during a dark or the windless period in the summer or under the dark cover of the winter ice and snow.

Macrophytes

Macrophytes are those aquatic plants which grow in extremely wet soil and water are available to the plants in the abundance. All to the way they develop in the water they are further, subdivided into the three groups they are floating submerged and emergent macrophytes. The aquatic macrophytes contain true angiosperm including water masses and sometimes even cataphora.

Macrophytes are classified according to their habitat, the major division is based on their attachment by the root to a solid substrate. The two divisions free floating and rooted macrophytes are common in lakes and other water free floating and rooted macrophytes are common in lakes and other water bodies. Rooted macrophytes are partly or completely submerged in the water bodies. Rooted plants have the advantage of being able to consume the littoral nutrient. They remove nutrient from the sediments and return to the surrounding water through excretion and the decomposition.

Macrophytes can cover the entire bed lake, if the water is shallow and transparent. In the deep shallow lakes, the macrophytes often become enveloped by a carbonate crust which may protect them from the solar radiation and animals grazing. Emergent monocotyledon angiosperm is the dominant macrophytes in the marshes and along the many streams course. The algal concentration and the number of the sediments turbidity in the higher amount course to reduce the number of the macrophytes. Many macrophytes are cultured, especially emergent macrophytes, the delicious plant like Rovio or aquarium is found in permanent and the temporary stream.

There are relatively few pelagic i.e free-floating macrophytes than rooted macrophytes. In the temperate and the subtropical region much smaller free-floating macrophytes are found such as duckweeds i.e Lemna and Azolla i.e fern.

Most macrophytes are frequently the primary source of the organic matter to the fresh water. Most aquatic macrophytes are bit used for food. However, the seeds of the angiosperm are favoured food for many birds and shelter provided by their foliage is important for small invertebrates and the eggs and young fishes.

Microbiology of the fresh water

Freshwater microbiology consists different life forms of microorganism i.e bacteria, fungi, unicellular algae, protozoa and the smallest metazoans like rotifers.

Many members of the bacterial microorganism of the actinobacteria, flavobacterium, micrococcus, bacillus, pseudomonas, Nocardia, streptomycin, microzoospore, hypophagia, spirillum and vibrio are reported as occurring widely in the lake water. The cyanobacteria microcystins, Anabaena, and Aphanizomenon can be dominant plankton in freshwater habitat. Chemolithotrophic bacteria have the important role in the nitrogen Sulphur and the iron cycling within lakes members of the genera nitro monas, Nitrobacter and thiobacillus are essential members of the freshwater microbial communities. Many fungi in the freshwater bodies are associated with foreign organic matter and thus should be considered as the associated with foreign organic matter. Thus should be considered as the ascomycetes and the fungi imperfectly and found on wood and dead plants material in the river and lakes when the plant material id degraded the associated fungi disappear. Yeast is found in many freshwater bodies weakly fermentative member of coreopsis candida, rho do torula and Cryptococcus are the yeast most commonly found in rivers streams and lakes. The fresh algae include members of the chlorophycophyta , euglenophycophyta, chrysophyophyta, phytoplankton and pyrrhophycophyta. Species of the algae, dinoflagellates and diatoms dominate in the most freshwater ecosystems in the aquatic habitats. Protozoa i.e amoeboid, ciliated and flagellated protozoa are found in the stream, rivers, and lakes. Numerous protozoa found in the freshwater habitat including common protozoa i.e paramecium, didymium, vorticella, Stentor, and amoeba. The flagellate protozoan body is common in polluted, low oxygen water.

References:

Miller, Jr. G.T. Living in the Environment. Wadsworth Publication, 2003.

S.C., Santee. Environmental Science. India, New Center: New Center Book Agency (P) Ltd, 2004.