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Lichen transplants at our service for atmospheric NH3 deposition assessments
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Orientador(es)
Resumo(s)
Atmospheric ammonia (NH3) is increasingly a major
worldwide driver for biodiversity loss. Because this pollutant
undergoes rapid chemical inter-conversions and deposition, it can be
challenging to monitor. Our aim was to develop a biomonitoring
system to evaluate atmospheric deposition of NH3. To do this, we
measured concentrations of several N-related variables in lichen
transplants including intercellular, extracellular, and bound fractions
of ammonium (NH4
+); total nitrogen; and carbon to nitrogen ratios.
We found extracellular NH4
+ to be the best indicator of atmospheric
NH3 deposition in 15-day lichen transplants. For transplants exposed
longer than 15 days, intercellular NH4
+ was the best indicator of NH3
deposition. Equilibration is achieved quite rapidly: bound NH4
+
equilibrated in less than 15 days and 35-day transplants accumulated
72 % of the extracellular NH4
+ concentrations present in in-situ
lichens. Changes in total N concentrations also occurred very rapidly;
a twofold increase in N concentration was observed in 35-day lichen
transplants. The lichen transplants proved to be good monitors of
short-term spatial and temporal variations in atmospheric NH3. Lichen
transplants can help to standardize biomonitoring procedures since
they have the same background levels and can be exposed in the same
conditions.
Descrição
Palavras-chave
Biomonitor NH3 Atmospheric pollution Ecological indicators nitrogen pollution Eutrophication Usnea Ammonium Total nitrogen
Contexto Educativo
Citação
Biology of Lichens – Symbiosis, Ecology, Environm. Monitoring, Systematics, Cyber Applications. Thomas H. Nash III et al. (ed.): Bibliotheca Lichenologica 105: 103–112. J. Cramer in der Gebrüder Borntraeger Verlagsbuchhandlung, Stuttgart 2010