Environmental Engineering Reference
In-Depth Information
Differentiated
Eukaryotes
Plants
Fungi
Animalia
Protista
(Undifferentiated
Eukaryotes)
Protozoa
Algae
Monera
Bacteria
Cyanobacteria
FIGURE 9.18
Organisms and microorganisms participating in natural bioremediation processes grouped according to
the Whittaker 5-kingdom hierarchical system. (From Yong, R.N. and Mulligan, C.N., Natural Attenuation of
Contaminants in Soils , CRC Press, Boca Raton, FL, 310 pp., 2004.)
are photosynthetic, they can produce oxygen, new cells from carbon dioxide or
bicarbonate HCO ( ) , and dissolved nutrients including nitrogen and phosphorus.
They use light of wavelengths between 300 and 700 nm. Red tides are indicative
of excessive growth of dinolagellates in the sea. The green color in a body of lakes
and rivers is eutrophication due to the accumulation of nutrients such as fertilizers
in the water.
• Although viruses are smaller than bacteria and require a living cell to reproduce,
their relationship to other organisms is not clear. For them to replicate, they have
to invade various kinds of cells. They consist of one strand of DNA and one strand
of ribonucleic acid (RNA) within a protein coat. A virus can only attack a speciic
host. For example, those that attack bacteria are called bacteriophages.
• The most signiicant animals in the soil are millimeter-sized worms. Nematodes
are cylindrical in shape and are able to move within bacterial locs. Flatworms
such as tapeworms, eel worms, roundworms, and threadworms, which are nema-
todes, can cause diseases such as roundworm, hookworm, and ilaria.
• Bacteria are prokaryotes that reproduce by binary ission by dividing into two
cells, in about 20 min. The time it takes for one cell to double, however, depends on
the temperature and species. For example, the optimal doubling time for Bacillus
subtilis (37°C) is 24 min and for Nitrobacter agilis (27°C) is 20 h. Classiication is
by shape, such as the rod-shaped bacillus, the spherical-shaped coccus, and the
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