Volume 508, 1 March 2015, Pages 7–12
Highlights
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- Biofilms on needles in a city area consist of algae, fungi and particulate matter.
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- High short-term NO2 levels lead to higher abundance of algae and biofilm cover area.
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- PM10 concentrations were negatively correlated with abundance of algae on needles.
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- Yew needle longevity was not correlated with the local air pollution levels.
Abstract
Excessive
occurrence of microalgae on needles of gymnosperms was reported for the
first time in the 1980s from the Scandinavian countries. Since then, it
has been repeatedly encountered on needles from various European forest
habitats. The abundance of these biofilms has been related to the
climatic conditions, such as temperature and precipitation, as well as
to the air pollution by nitrogen and sulfur oxides. Urban areas
typically have relatively homogenous climates and profound variation in
levels of air pollution. Therefore, variation in the occurrence of
biofilms in localities within an urban area may be related to local
anthropogenic air pollution. We investigated the abundance of biofilms
occurring on needles of the common yew (Taxus baccata) in the
city of Prague, Czech Republic. The biofilms were composed of algae,
fungi and particulate matter. The cover area of the biofilms was
marginally explained by a positive influence of short-term maximum
atmospheric levels of nitrogen dioxide (NO2). The amounts of the microalgae were also positively influenced by short-term maximum NO2 levels. In addition, high atmospheric levels of particulate matter (PM10)
were related to low abundance of algae. The microbial biofilms growing
on widely cultivated conifers, such as the common yew, form one of the
few commonly occurring natural communities in highly urbanized central
areas of temperate European cities. Consequently, we propose that
microscopic analysis of biofilms may be used as a rapid and cheap method
to collect ecological data. Such data may be used in biomonitoring
schemes illustrating the effects of anthropogenic air pollution on
natural microcommunities in urban areas.
Keywords
- Subaerial biofilms;
- Biomonitoring;
- Microalgae;
- Air pollution;
- Trebouxiophyceae;
- Common yew
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