Sample Processing - Equipment & Suppliers

EQUIPMENT AND MATERIALS

The following items are used in the processing and analysis of meiofaunal samples. Those marked with an asterisk (*) are specialised items, details of which are given below. Unless otherwise stated, the majority of these items are available from most laboratory suppliers.

1. Processing samples

2. Processing meiofauna

Making a subsampler

Bend the handle of a kitchen ladle so that it hangs with the bowl horizontal and the handle as near vertical as possible. Fill the bowl with water and measure the volume twenty times. Find a container with a flat bottom and vertical sides, made from a reasonably strong and rigid transluscent plastic, with a volume about thirty times that of the ladle. Such a container can often be made by cutting the top off a chemical reagent container. Measure a volume of water equivalent to twenty times the volume of the ladle into the plastic container, place it on a horizontal surface and allow it to settle. Mark the level of the meniscus with a permanent marker at various points around the container. Carefully remove one ladle full of water, and mark the position of the meniscus again. Repeat this process to give a series of marks on the container denoting volumes equivalent to various numbers of ladles. Note that minor errors in the volume extracted add up, so using this method to remove more than about a quarter of the sample (5 ladle volumes) begins to become unreliable.

The wax-applicator

Any metal-workshop should be able to construct an adequate applicator from the design given below. A version is also available from Spartel (see below).

Quills and fine needles

For the manipulation of extracted samples in glycerol a firm but flexible, non-absorbent tool is very helpful. Strange though it may sound, one tool which has been found to have the required properties is a section of quill, cut from the wing feather of a resonably large bird (a herring gull for example), and mounted on a wooden handle. Pieces of plastic have also sufficed, but have been found to be, in general, somewhat stiff.

Fine needles can be made from 0.25 - 0.35mm tungsten wire. To sharpen such needles an electrolytic technique may be used. The tungsten needle is attached to the positive terminal of a 6V DC power supply (such as powers many microscope lamps) using a crocodile clip. A wire or carbon cathode is immersed in a small bath containing saturated KOH solution and attached to the negative terminal of the power supply. The power is turned on and a fine point produced on the needle by gently moving it up and down in the electrolyte. The resulting needle is mounted in a pin-vice or needle holder for use.

Some UK suppliers who can provide equipment mentioned above are shown below.

Laboratory Supplies

Chemicals

Microscopical Supplies

Specialised equipment (samplers, wax applicator etc.)

These companies are by no means the only ones capable of supplying the majority of the equipment and materials indicated, and mentioning a company by name is not intended as an endorsement of that company in preference to others, similarly not mentioning a company does not imply lack of endorsement.