A QUANTITATIVE METHOD FOR THE COLLECTION AND MEASUREMENT OF STREAM PERIPHYTON1

Two methods for the collection and estimation of stream periphyton production are presented. The periphyton was collected on 1.4 din2 plexiglass plates attached to a horizontal crossbar. The crossbar was supported by a vertical post clriven into the stream bottom or supported by a concrete block. The plates were removed from the stream and the cstablishcd population estimated by dctcrmining the absorbency of the ethanol-soluble phytopigments and by gravimetric proccdurcs. h r&able estimate of the population can be made from the phytopigment absorbency values if the latter are corrected for deviations from the absorbcncy:conccntration relation-ship and if the substrata are removed from the stream before the growth is too profuse. Conficlcncc limits are given for the phytopigment dcnsity:wcight of organic material relationship