Mary E. Power, Michael S. Parker, and William E. Dietrich. 2008. Seasonal reassembly of a river food web: floods, droughts, and impacts of fish. Ecological Monographs 78:263–282.

Appendix C. Methods for core sampling.

We used a 9-cm diameter plastic sampling core (on three dates, slightly smaller cores were used (Table 1)), with a nylon stocking sleeve secured over the upper end. The stocking sleeve (< 0.3 mm mesh) was fastened with an elastic band around the upper arm with the hand and lower arm passing through the core. We pressed the bottom edge of the core against the rock substrate underwater, scraping algae and associated biota from the substrate with fingers until no more adhering organic matter could be felt. A thin plastic lid was then slid across the bottom of the corer, and the sample lifted to the water surface, allowing water to drain through the nylon mesh, which retained the sample. A 4-L ziplock bag was then secured over the corer bottom. Dipping and quickly withdrawing the corer from the water backflushed most material from the corer and the sleeve into the ziplock bag. Residual sample material clinging to the mesh or the core was rinsed into the bag with river water.

Small amounts of algae were removed with forceps from each sample for microscopy and preserved in 2% formalin for taxonomic assessment. Then samples from the three cores (total area of 191 cm²) were pooled and preserved in 70% ethanol. In the laboratory, invertebrates in these algal samples were extracted, measured (total length) under 10× magnification, and identified to the lowest possible taxonomic order (usually family or genus). Algae were spun for 50 revolutions in a salad spinner, and weighed damp.