Bottom Substrate

Bottom Substrate

The substrate is of sufficient importance in the ecology of algae to make it possible to refer to different types of communities.

Bottom substrate (sediment) is the material that rests at the bottom of a stream or lake. There are several classification guides. One is:

Mud – silt and clay.
Sand – Particles between 0.06 and 2 mm in diameter.
Granule – Between 2 and 4 mm in diameter.
Pebble – Between 4 – 64 mm in diameter.
Cobble – between 6.4 and 25.6 cm in diameter
Boulder – more than 25.6 cm in diameter.

Bottom substrate can affect the life found within the stream habitat. Muddy streams generally have more sediment in the water, reducing clarity.

The stability of the substrate of the substratum is important. The effect of streambed stability in reducing the numbers of algae has been noted on stones which were rolled by the water in comparison to stones that remained fixed in the stream bed.

On the whole, larger species of algae are confined to solid objects rather than to plants and the slower growing ones. Rhodophyta, are found on stable materials such as rocks and large stones.

Different types of stone in a stream bed often acquire different amounts of flora as sometimes can be seen near bridges where alien stones, bricks and concrete are mingled with native rock.

Controlling Factors of Algae Growth are briefly discussed.
Scour of Algae
Alkalinity and Algae
Nutrients and Algae
Grazing Aquatic Animals

Next Topics about Algae…
Blue-green Algae
Green Algae
Yellow-Golden-brown Algae and Diatoms
Brown Algae
Red Algae
Significance of Algae

Next Topics…
Liverworts and Mosses
Vascular Plants

Go Back to:
Physical Water Quality
Chemical Water Quality
Biological Water Quality
Water Basics 101

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