DIATOMS AND DINOFLAGELLATES (CLASSIFICATION, ECOLOGY, APPLICATIONS)pptx

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1. DIATOMS AND DINOFLAGELLATES M. CHATIYAA I – M. Sc MICROBIOLOGY DEPT. OF MICROBIOLOGY SACRED HEART COLLEGE

2. DIATOMS CLASSIFICATION DOMAIN : Eukaryota KINGDOM : Protista PHYLUM : Ochrophyta CLASS : Bacillariophyceae

3. CHARACTERISTICS OF DIATOMS Diatoms are group of algae. Unicellular and eukaryotic i n nature. They are producers within the food chain. Cell wall made of silica, referred as frustule.

4. Cont. Non motile organisms. Reproduce asexually by binary fission. Diatoms form colonies in the shapes of filaments (e.g, Fragilaria ), fans (e.g, Meridion ), zigzags (e.g, Tabellaria ), and stars (e.g, Asterionella ). Originated during, or before, the early Jurassic period. More than 200 genera of living diatoms are known.

5. Diatoms are photosynthetic organisms.
Presence of pigments such as fucoxanthin and beta carotene give them characteristic golden color.
Store energy in the form of chrysolaminarin (a carbohydrate) and lipids.
High production of lipids in diatoms created it as a source of biofuels. Cont.

6. ECOLOGY Diatoms are found in fresh water ( Denticula tenuis , Navicula pupula , Meridion circulare , Cymbella ventricosa , Melosira variens , Amorpha ovalis ). In sea water ( Corethron , Biddulphia , Sceletonema , Fragilaria ). In soil ( Pinnularia , Navicula , Frustulia ).

7. APPLICATIONS After the death of diatom cells, outer coverings become accumulated at the bottom of water. These deposits called diatomite which is used as filter in sugar, oil industries (to filter microorganisms). Used as filter for battery boxes. Used as absorbent of liquid nitroglycerine.

8. Used to test microscopic lenses.
Tool for monitoring environmental conditions.
Used in studies of water quality.

9. DINOFLAGELLATES CLASSIFICATION DOMAIN : Eukaryota KINGDOM : Protista SUB KINGDOM : Dictyozoa PHYLUM : Dinocoa SUB PHYLUM : Dinoflagellate

10. CHARACTERISTICS OF DINOFLAGELLATES Dinoflagellates are group of algae. Unicellular and eukaryotic in nature. They are producers within the food chain. Cell wall made of cellulose plates, referred as theca.

11. Cont. The dinoflagellate nucleus called dinokaryon. The chromosomes attached to the nuclear membrane carry reduced number of histones. Dinoflagellates are motile organisms characterized by the presence of dissimilar flagella arising from the ventral cell side. Some dinoflagellates exhibit bioluminescence (emit blue green light)

12. Cont. Forms endosymbiotic relationship between Symbiodinum and reef- building corals. Occurance of blooms are associated with the production of neurotoxins which injure the nerves of marine life that feed on dinoflagellates . Reproduce asexually by binary fission. 1,555 species of free- living marine dinoflagellates have been described.

13. ECOLOGY Dinoflagellates are found in marine water ( Noctiluca miliaris ). In fresh water ( Peridinium willei ).

14. APPLICATIONS Dinoflagellates cyst are Biostratigraphical indicators. They are very important to indicate salinity. It can generate 90 percent of oxygen and hence useful for humans. Useful in indicating climatic changes.