Study on productivity of epilithic algae in Urumqi River Basin in Northwest China

摘要

The primary objective of this study was to make a deep investigation on the concentration of chlorophyll a and?ash-free dry mass (AFDM)?estimates for algae growing on stones in Urumqi River located in an arid region of northwest China. The study was conducted on three sites. A highly improved method for measuring primary productivity?in situ?was used to estimate the primary production of algae growing on rocks (or algae epilithic) deposited in surface water. The results showed a low biomass with mean chlorophyll a content that was estimated at 5.9 mg/m2in the Urumqi River. Of the three sites studied, the mean gross primary productivity of periphyton was 394.89 mgC/m2?day?and AFDM 344.75 mg/m2. The analysis of correlation between chlorophyll a and altitude was found to be a curve of anti- hyperbola. Total phosphorus and chlorophyll a was in equilibrium with that between chlorophyll a and total nitrogen.