7891 - Laserfiche WebLink

Home Browse Search

pool habitats should be sampled with grab samplers. Eddies and backwaters should be sampled using core and grab samplers. A minimum of 6 mples should be collected from throughout each major habitat type within each reach and composited. Samples from different habitat types or different reaches should always be kept separate. Qualitative samples should be collected to provide additional data on less abundant taxa. Qualitative samples should be collected with a kick or sweep net and by inspecting individual rocks and twigs for rarer taxa. Adult aquatic insects encountered during a site visit should also be collected. All samples should be preserved in 95% ethanol or Kahle's solution (28% fonnalin + 28% ethanol + 2% acetic acid + 59"/0 water). Sample bottles should be labeled both inside and out. Inside labels should be written in pencil on water proof paper. Outside labels should be written on in pencil on masking tape or directly on the bottle with an alcohol proof pen. Periphyton Periphyton production should be estimated in cobble habitats using periphyton scrapes from approximately Dso sized rocks. Periphyton should be collected by isolating a small area with a rubber-gasketed template and scraping it with a X-acto #17 knife blade (Angradi and Kubly 1993). Dislodged material should then be removed with forceps. The scraped area should then be flushed with water, scrubbed with a brush, and the water and any material removed with a dropper. Ten samples of this type should be collected at each site during each sampling visit. Periphyton samples should be kept cold (<4 C) and then frozen upon returning to the laboratory. In the laboratory, this material should be thawed, dried at 600C until a constant weight is attained, weighed, and fired in a muftle ~ at 550~C for 2 hours to obtain ash-free dry mass (AFDM). 8