Select a reference point in the middle of your site and on one bank drive a peg into the ground.
• Attach the tape measure to the peg and lay it out taut across the stream. Anchor the far end with the second peg.
• Divide the width of the stream (water's edge to water's edge) into 10 equally spaced
intervals.
• Move out to the first point across the transect (this will be near the water's edge on one side of the stream). Press the sampler firmly against the boulder/bed rock at this
selected point, ensuring that there is a good seal around the base. The horizontal
syringe should be inserted in the base of the main syringe as illustrated in Figure 9.
• Push the plunger down in the first syringe so that the brush is in contact with the
substrate. Turn the plunger three full rotations to the right, then three full rotations to
the left
• Draw some water into the vertical syringe by raising the plunger about 1 cm. Then
draw this water/periphyton mixture into the horizontal syringe (this takes some
dexterity, but is reasonably easy with practice).
• Carefully remove the apparatus from the water and discharge the sample into its
appropriate container. Rinse off the brush into the container.
• Store the labeled container of periphyton sample on-ice in a chilli-bin for transport to
the laboratory.
• The recommended number of rotations of the plunger may be insufficient to remove
tightly attached periphyton. If possible test the method in a shallow area, or on a stone that can be retrieved at your site, so that you can check periphyton removal efficiency before using it for proper sample collection. If necessary increase the number of rotations, but then ensure that you use this number consistently for all samples.
Note: Cattaneo and Roberge (1991) have tested the efficiency of this sampler for removal of periphyton in streams and lakes. They found that it depends largely on the relative proportions of loosely and tightly attached community. In stream, the syringe sampler tended to underestimate biomass, and the severity of this underestimation increased with water velocity under which the communities had grown. Thus, if it is necessary to use this sampler in streams, we recommend that for consistency within a study, it is used to collect all samples in that study.