Question

Water in abandoned swimming pools often turns green. If examined a drop of this water with a microscope, how could you tell whether the water contains protists and, if so, which group they might belong to?

Answer 1

Colonies present in water are protists .

Examination under microscope will reveal that:

presentatives may be in the form of single cells, colonies or
filaments and are usually blue-green (most common), grey, brownish,
blackish or even purple in colour, but never bright green. The
blue-green colour is the result of photosynthetic pigments such as
chlorophyll-a (green pigment) and phycocyanin (blue pigment). Some
also contain phycoerythrin (a red pigment). When all three pigments
are present, the cells may appear purplish. No flagellated stages are
present, but some filaments can perform gliding movements. A
characteristic feature of many blue-green algae is the presence of gas
vacuoles in the cells, which provide buoyancy to the organism. Cells
are covered with a thick, layered cell wall that is often surrounded by
mucous. Sexual reproduction is absent. The group include marine as
well as freshwater, brackish water and terrestrial species. Under
conditions of excessive nutrient (primarily phosphorus) availability,
slow moving or stagnant water, and warmth, cyanobacteria may
proliferate, producing a variety of problems such as surface scums,
tastes and odour problems, skin irritations and the release of toxic
substances. When these blooms decompose, severe oxygen
depletion may occur, resulting in fish kills.

Hope this helps.

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