Affiliations: Department of Biology, Faculty of Science, Razi
University, Baghabrisham 67149, Kermanshah, Iran | Tabriz Botanical Garden, East Azerbaijan Agriculture
and Natural Resources Research Center Azarbaijan Square, Tabriz 51879-33151,
Iran | Razi University Centre for Environmental Studies,
Baghabrisham 67149, Kermanshah, Iran
Abstract: In order to evaluate the long-term (24-day) influence of copper
alone (Cu) and with combination of Cu+Zn on biomass and taxonomic composition
in algal periphyton communities, indoor artificial streams were used with
copper (50 μg.l-1) and copper and zinc (50 μg Cu l-1 and 1 mg Zn l-1). The
effects of copper and zinc on community productivity were assessed by measuring
biomass, ash-free dry mass (AFDM), chlorophyll-a, taxonomic composition,
relative abundance and biovolume. In artificial streams with Cu and Cu + Zn,
there was a significant (p < 0.05) reduction of chlorophyll-a, dry mass and
AFDM. Species diversity and relative abundance of periphyton species changed
drastically under the influence of copper and zinc. In an artificial streams
containing copper and zinc (50 μg Cu l-1 and 1 mg Zn l-1), the taxonomic
composition of the population shifted from a cyanophyceaen dominated community
to a community mainly consisting of chlorophyceae, while changes among species
within the bacillariophyceae did not show a marked difference under the
influence of copper and zinc. In artificial streams with copper alone Oocystis
gigas and Stigeoclonium tennue became dominant species while in artificial
streams containing copper and zinc Oocystis crassa and Scenedesmus sp.
dominated the periphyton community. This study showed that copper alone or with
combination of zinc not only influences community productivity but also causes
changes in species composition.
