EFFECTS OF ADDED NUTRIENTS ON DRY MASS, AFDM, CHLOROPHYLL a AND BIOVOLUME OF PERIPHYTON ALGAE IN ARTIFICIAL STREAMS

Document Type: Regular Paper

Authors

1 Department of Biology, Faculty of Science, Razi University, Baghabrisham, Kermanshah, 67149, I. R. of Iran,

2 Department of Biology, Faculty of Science, Razi University, Baghabrisham, Kermanshah, 67149, I. R. of Iran

Abstract

We studied the role of nutrients on various aspects of the periphyton community in artificial
streams. Dry mass, ash-free dry mass, chlorophyll a and biovolume of the periphyton community were
measured under 3 different nutrient regimes, including one from natural streams as a control and two
which were enriched with N and N+P. Results of this experiment indicate that the standing crop of the
periphyton community in the artificial streams increased with increasing the amount of the nutrient.
Also, we showed that diatom diversity was affected by increasing the nutrients concentrations. The
periphyton dry mass following 23 days of experiment was 0.96, 1.4 and 3.52 mg/cm2 for control, N and
N+P artificial streams, respectively. Ash-free dry mass (AFDM) of the periphyton community for
control, N and N+P treatment were 0.2, 0.98 and 1.04 mg/cm2, respectively. The experiment also
depicted that the periphyton chlorophyll a increased with increasing the nutrient content in the artificial
streams (for control, N and N+P enriched artificial streams, the chlorophyll a content was 2.11, 2.20 and
6.36 mg/m2respectively). The total diatom biovolume as a measure of standing crop in the periphyton
community was 6x106, 8x106 and 48x106 μm3/cm2 for control, N and N+P enriched artificial streams,
respectively. Results of this experiment demonstrated that adding nutrient increases the relative
abundance of Navicula, Achnanthes, Nitzschia and Cocconies in artificial streams.

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