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Naghavian, Navid, 2012. Experimental zinc stress on benthic diatoms assemblage growth in Fyrisån water. Second cycle, A2E. Uppsala: SLU, Dept. of Aquatic Sciences and Assessment

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Abstract

Benthic diatoms are unicellular, brown algae with siliceous cell walls. They are often used to show water quality in river sand lakes. Benthic diatoms can show elevated nutrient levels, very acid conditions, pollution by organic matter and probably also pollution by heavy metals, which makes them useful biological indicator species. Observed impact of metal pollution on benthic diatoms are reductions in cell number, valve malformation and reduction of some diatom taxa which leads to a change in community structure. The present study is focusing on the impact of the heavy metal zinc.
In aquatic environments, zinc exists in form of divalent cation Zn2+, hydrated zinc (pH=4-7) and moderately weak complexes. At higher pH (7-10) Zn2+ is replaced by adsorbed Zinc (ZnFe(OH)3), or aqueous ZnCO3and Zn(OH)2.. Zinc release to soil and aquatic environments may be from mining, smelting metals, steel production, waste incineration, burning coal and fossil fuel.
Two hypotheses were tested in laboratory experiments in the present project:
1. The culture of benthic diatoms is possible under the given laboratory (artificial) conditions.
2. High concentrations of zinc (300μg/l zinc) decrease the number of benthic diatoms and increase abnormalities in cell walls.
The first hypothesis “The culture of benthic diatoms is possible under the given laboratory (artificial) conditions.” was confirmed. Diatom cell numbers increased during the course of the first experiment.
The second hypothesis that “High concentrations of zinc (300μg/l zinc) decrease the number of benthic diatoms and increase abnormalities in cell walls.” was not confirmed by this experiment, possibly due to the loss of the toxic zinc form from solution over time.

Main title:Experimental zinc stress on benthic diatoms assemblage growth in Fyrisån water
Authors:Naghavian, Navid
Supervisor:Gottschalk, Steffi and Kahlert, Maria and Köhler, Stephan
Examiner:Fölster, Jens
Series:UNSPECIFIED
Volume/Sequential designation:UNSPECIFIED
Year of Publication:2012
Level and depth descriptor:Second cycle, A2E
Student's programme affiliation:NM010 Soil and Water Management - Master's Programme 120 HEC
Department:(NL, NJ) > Dept. of Aquatic Sciences and Assessment
Keywords:Benthic diatoms, heavy metal contamination, valve malformation, heavy metals, DOC, TOC, water assessment
URN:NBN:urn:nbn:se:slu:epsilon-s-1807
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-s-1807
Subjects:Aquatic ecology
Water resources and management
Pollution
Language:English
Deposited On:25 Oct 2012 08:57
Metadata Last Modified:07 Nov 2012 10:08

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