What causes diatoms, filamentous & Algae?

What causes diatoms, filamentous & Algae? – Nitrogen is considered the limiting factor for algal growth in salt water, while phosphorus is the limiting factor in fresh water.

Under optimal conditions heterotrophic bacteria can double their population in 20 minutes; algae take about 24 hours. The bacteria also have a much greater surface area to volume ration than algae which facilitates the uptake of nutrients.

The bacteria in Cycle and Waste Control are used in decorative ponds to help keep water clearer and to out-compete diatoms, filamentous and blue-green algae. Regular additions of Cycle and Waste Control are essential to maintain the competitive pressure on the algae. The nutrients taken into the bacteria are unavailable to the algae. Bacteria are rapidly preyed upon; this results in the nutrients being channeled into the faunal food web.

Diatoms have the special requirement of silica for their growth. Filamentous algae are favored in moving water. The attached filaments remain in position, whereas planktonic forms move downstream with the current. Blue-green algae can fix nitrogen from the air and also form air pockets, which make them float at the surface. Blue-green algae often occur in polluted water, which is turbid. Their ability to float provides them with light in otherwise dark waters.