Algae commonly grow in any habitat that is moist or where standing water can be found. This includes fresh water, salt water, ice, air, and even in or on other organisms or substrate. In most areas algae fare better in summer rather than winter.
Algae are often regularly found in communities, living within many other different species of plankton, algae, and zooplankton. These communities can tell a lot about the health of an ecosystem. For example, a community of Euglena (a type of Algae), Scenedesmus (genus of Algae - specifically of the Chlorophyceae) and Selenastrum likely indicates a body of water that is rich in mineral and organic nutrients.
Water may be tested for algae content by placing a sample of water on a well depression slide, covering it with a cover slip and viewing at 40x, 100x, or 400x under a biological microscope.
|Image of Selenastrum courtesy of Silken Tent.|
|Image of Scenedesmus courtesy EPA.|