1.0 INTRODUCTION

Cyanobacteria are aquatic andphotosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see. They have the distinction of being the oldest known fossils, more than 3.5 billion years old, in fact! It may surprise you then to know that the cyanobacteria are still around; they are one of the largest and most important groups ofbacteriaon earth.Cyanobacteria, formerly called "blue-green algae" are relatively simple, primitive life forms closely related to bacteria. Typically much larger than bacteria, they photosynthesize like algae. Depending upon the species, cyanobacteria can occur as single cells, filaments of cells, or colonies. Cyanobacteria contain a characteristic pigment which gives the group their blue-green coloration. When cyanobacteria blooms begin to die and disintegrate, this pigment may color the water a distinctive bluish color. Cyanobacteria are found throughout the world in terrestrial, freshwater and marine habitats, but blooms typically occur in freshwater.The algae are the simplest members of the plant kingdom, and the blue-green algae are the simplest of the algae. They have a considerable and increasing economic importance; they have both beneficial and harmful effects on human life. Blue-greens are not true algae. They have no nucleus, the structure that encloses the DNA, and no chloroplast, the structure that encloses the photosynthetic membranes, the structures that are evident in photosynthetic true algae. Infact blue-greens are more akin to bacteria which have similar biochemical and structural characteristics. The process of nitrogen fixation and the occurrence of gas vesicles are especially important to the success of nuisance species of blue-greens. The blue-greens are widely distributed over land and water, often in environments where no other vegetation can exist. Their fossils have been identified as over three billion years old. They were probably the chief primary producers of organic matter and the first organisms to release elemental oxygen, O2, into the primitive atmosphere, which was until then free from O2. Thus blue-greens were most probably responsible for a major evolutionary transformation leading to the development of aerobic metabolism and to the subsequent rise of higher plant and animal forms. They are referred to in literature by various names, chief among which are Cyanophyta, Myxophyta, Cyanochloronta, Cyanobacteria, blue-green algae, blue-green bacteria.Many Proterozoic oil deposits are attributed to the activity of cyanobacteria. They are also important providers of nitrogen fertilizer in the cultivation of rice and beans. The cyanobacteria have also been tremendously important in shaping the course of evolution and ecological change throughout earth's history. The oxygen atmosphere that we depend on was generated by numerous cyanobacteria during theArchaeanandProterozoicEras. Before that time, the atmosphere had a very different chemistry, unsuitable for life as we know it today.The other great contribution of the cyanobacteria is the origin ofplants. The chloroplast with which plants make food for themselves is actually a cyanobacterium living within the plant's cells. Sometime in the late Proterozoic, or in the early Cambrian, cyanobacteria began to take up residence within certaineukaryotecells, making food for the eukaryote host in return for a home. This event is known asendosymbiosis, and is also the origin of the eukaryotic mitochondrion.Unicellular and filamentous blue-greens are almost invariably present in freshwater lakes frequently forming dense planktonic populations or water blooms in eutrophic (nutrient rich) waters. In temperate lakes there is a characteristic seasonal succession of the bloom-forming species, due apparently to their differing responses to the physical- chemical conditions created by thermal stratification. Usually the filamentous forms (Anabaena species, Aphanizomenon flos-aquae and Gloeotrichia echinulata) develop first soon after the onset of stratification in late spring or early summer, while the unicellular-colonial forms (like Microcystis species) typically bloom in mid-summer or in autumn. The main factors which appear to determine the development of planktonic populations are light, temperature, pH, nutrient concentrations and the presence of organic solutes.Because they are photosynthetic and aquatic, cyanobacteria are often called "blue-green algae". This name is convenient for talking about organisms in the water that make their own food, but does not reflect any relationship between the cyanobacteria and other organisms called algae. Cyanobacteria are relatives of the bacteria, not eukaryotes, and it is only thechloroplastin eukaryotic algae to which the cyanobacteria are related.

2.0 MATERIALS

2.1 Microscope slide2.2 Coverslip2.3 Dissecting needle2.4 Compound microscope2.5 Oscillatoria living culture2.6 Disposable pipet

3.0 PROCEDURES

3.1 A small amount of culture taken outside of the laboratory. Commonly at the drain.3.2 Dissecting needle used to scrape some of the culture from the surface.3.3 A wet mount slide prepared.3.4 The slide examined under compound microscope.3.5 Portion of the filament draw as in the diagram 3.4.

4.0 RESULT

Cyanobacteria under microscope ( 40x10 magnification )

5.0 DISCUSSION

6.0 CONCLUSION

Not all of the Oscillatoria cells look alike and there is differentiation of certain cells within the filament.

7.0 REFERENCES

Introduction to the Cyanobacteria: Architects of earths atmosphere. (n.d). Retrieved on Jan 21st, 2013 from http://www.google.com/search?client=msnokia&cof=nsp&channel=s60&hl=zh-CN&ie=UTF-8&q=introduction+to+cyanobacteria

Niharika Arya. (June 19, 2012). Buzzle:Eubacteria Kingdom. Retrieved on February 13, 2013 from http://www.buzzle.com/articcles/eubacteria-kingdom.html

8.0 APPENDICES

Figure 8.1 Cyanobacteria (400X)

Figure 8.2 Cyanobacteria under microscope ( 40x10 magnification )