INTRODUCTION
Where Do 'Freshwater Algae' Grow?
How Do I Collect, Preserve & Observe Freshwater Algae?
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Freshwater
Algae
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INTRODUCTION
| How to Collect Freshwater Algae | How to Preserve Freshwater Algae | How to Observe 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.
The collector's name and collecting number should be pencilled onto the herbarium sheet (and later replaced with a full label) or onto a collecting tag inserted into the solution. The accompanying notes should include standard information such as the locality, date of collection, and the collector's name and collection number, and as many of the following features as possible: whether the water is saline, brackish or fresh; whether the collection site is terrestrial, or a river, stream or lake; whether the alga is submerged during water level fluctuations or floods; whether the water is muddy or polluted; whether the alga is free floating or attached, and if the latter, the type of substrate to which it is attached; and the colour, texture and size of the alga.