Collecting freshwater algae
Collection methods
Macroalgae and the attached microalgae can be collected by hand or with a knife, including part or all of the substrate (rock, plant, wood etc.) if possible. Search all habitats in the waterbody including the edge of stones in fast-flowing water, aquatic plants, dam walls, and any floating debris.
In running or slightly turbid waters, a simple viewing box made from transparent perspex enables attached algae to be more easily observed. A hand lens is often useful to determine if material is reproductive (essential for species determination in some genera and helpful for generic placement).
Microscopic floating algae (the phytoplankton) can be collected with a mesh net (e.g. with 25-30 µm pores) or, if in sufficient quantity (i.e. colouring the water), by simply scooping a jar through the water. Water samples can be left overnight allowing the algae to settle and concentrate on the bottom of the container. Squeezing Sphagnum and other mosses, or some aquatic flowering plants such as Utricularia is a good way to collect a large number of species.
Microscope slides suspended in a waterbody for c. 2-4 weeks will reveal many species. The slides should be kept submerged until ready to examine under the microscope. One side can be wiped clean and a coverslip placed over the other.
Algae growing on soil are difficult to collect and study, many requiring culturing before sufficient and suitable material is available for identification.
|
