Sampling, Biomass Estimation and Counts of Freshwater Algae - Freshwater Algae: Identification, Enumeration and Use as Bioindicators - page 87

Figure 2.23 River periphyton.
Top: general view of fast-flowing
stream (left) with detail of rocky
substratum (right). Bottom left:
Detached periphyton sample obtai-
ned by scraping the stone surfaces,
showing a filamentous mat of
Phormidium (blue-green) attached to
dense organic material. Bottom right:
Stellate cluster of diatom (possibly
Synedra ) cells radiating out from a
single point of attachment.

Table 2.6 Shallow-Water Communities: Variations in Algal Collecting Method Depending on Substrate Type.

Substrate Type Collecting Method

Epilithic. Stones and rocks Remove stone and scrape surface with knife or brush with stiff brush. If stone

too large to remove hold a phytoplankton net downstream of the rock and
then scrape or brush so that the material removed is swept into the net.

Epidendric Woody material As above

Epipelic Sediment surface Gently suck up sediment surface using a pipette with a rubber teat or gently

scoop up the top layer of sediment into a suitable container.

Epiphytic Plant surfaces Scrape algae off the macrophyte surface, place in a tube with water and/or

preservative and observe later under a microscope.

Epipsammic Sand Collect a small quantity of sand from the surface region. Place in a tube with a

small quantity of water and shake vigorously. Allow to settle and pipette
off some of the settled material and place on a slide for observation. The
selection of sand grains should also be observed in case there are species
that have not been detached by shaking.

Epizooic Hard-shelled animals Carefully collect the host animal. Use the same technique as for the epilithon.