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Sökning: onr:"swepub:oai:DiVA.org:su-6818" > Heavy metal contami...

Heavy metal contamination and toxicity Studies of Macroalgae from the Tanzanian Coast

Mamboya, Florence Alex, 1971- (författare)
Stockholms universitet, Botaniska institutionen
Björk, Mats, Docent (preses)
Stockholms universitet, Botaniska institutionen
Ekelund, Nils, Prof (opponent)
Mittuniversitetet
ISBN 91-7155-374-6
Stockholm : Botaniska institutionen, 2007
Engelska 48s.
  • Doktorsavhandling (övrigt vetenskapligt)
Abstract Ämnesord
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  • <p>Concentrations of various metals are elevated above background levels in several intertidal areas along the Tanzanian coasts. However, there is little available information concerning the toxicity of these metals and how the uptake of these metals by bioindicators are influenced by external factors, such as heavy rains and increased coastal eutrophication, which tend to fluctuate.</p><p>The present study focused on the uptake and toxicity of Cu and Zn in two common macroalgal species,<i> Padina gymnospora</i> (Phaeophyta) and<i> Ulva</i> <i>reticulata</i> (Chlorophyta). Laboratory studies were performed where metal content, growth (DGR), maximal quantum yields (Fv/Fm) and protein expression patterns (in <i>Ulva</i>) were measured as a response to exposure to Cu and Zn. The levels of metals accumulated in algal tissues correlated well to exposure concentrations and the longer the exposure time, the greater the uptake. However, an increased nutrient load (tested on <i>Padina</i>) or dilution of the seawater (tested on<i> Ulva</i>) affected both uptake of metals and their toxic effects. Here, DGR was more affected than Fv/Fm, suggesting DGR to be the more sensitive indicator of Cu and Zn toxicity. As shown by 2-D gel electrophoresis, more than ten proteins were up-regulated in <i>U. reticulata</i> after being exposed to Cu (1μg/L), while at higher concentrations (10 and 100 μg/L) of Cu numerous proteins were down-regulated.</p><p><i>P. gymnospora </i>was also used as a bioindicator to monitor long-term (1994–2005) and seasonal in-year variations in heavy metal concentrations in the Zanzibar Channel. No clear overall trends were revealed, but analysis of the combined dataset clearly pinpointed the most contaminated sites. It was concluded that seasonal and long-term variations, as well as environmental conditions need to be taken into consideration when using macroalgae as bioindicators.</p>

Ämnesord

NATURVETENSKAP  -- Biologiska vetenskaper -- Botanik (hsv//swe)
NATURAL SCIENCES  -- Biological Sciences -- Botany (hsv//eng)

Nyckelord

Heavy metals
Padina gymnospora
Ulva reticulata
salinity
nutrients
proteins
uptake
growth
Fv/Fm
Zanzibar Channel
NATURAL SCIENCES Biology Organism biology Plant physiology
NATURVETENSKAP Biologi Organismbiologi Växtfysiologi
växtfysiologi
Plant Physiology

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