BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
δ15N of lichens reflects the isotopic signature of ammonia source

Participants in the publication
S. Munzi (Author)
Cristina Branquinho (Author)
Dep. Biologia Vegetal
cE3c
C. Cruz (Author)
Dep. Biologia Vegetal
cE3c
C. Máguas (Author)
Dep. Biologia Vegetal
cE3c
I.D. Leith (Author)
L.J. Sheppard (Author)
M.A. Sutton (Author)

Summary
Abstract\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\nAlthough it is generally accepted that δ15N in lichen reflects predominating N isotope sources in the environment, confirmation of the direct correlation between lichen δ15N and atmospheric δ15N is still missing, especially under field conditions with most confounding factors controlled. To fill this gap and investigate the response of lichens with different tolerance to atmospheric N deposition, thalli of the sensitive Evernia prunastri and the tolerant Xanthoria parietina were exposed for ten weeks to different forms and doses of N in a field manipulation experiment where confounding factors were minimized. During this period, several parameters, namely total N, δ15N and chlorophyll a fluorescence, were measured. Under the experimental conditions, δ15N in lichens quantitatively responded to the δ15N of released gaseous ammonia (NH3). Although a high correlation between the isotopic signatures in lichen tissue and supplied N was found both in tolerant and sensitive species, chlorophyll a fluorescence indicated that the sensitive species very soon lost its photosynthetic functionality with increasing N availability. The most damaging response to the different N chemical forms was observed with dry deposition of NH3, although wet deposition of ammonium ions had a significant observable physiological impact. Conversely, there was no significant effect of nitrate ions on chlorophyll a fluorescence, implying differential sensitivity to dry deposition versus wet deposition and to ammonium versus nitrate in wet deposition. Evernia prunastri was most sensitive to NH3, then NH4+, with lowest sensitivity to NO3−. Moreover, these results confirm that lichen δ15N can be used to indicate the δ15N of atmospheric ammonia, providing a suitable tool for the interpretation of the spatial distribution of NH3 sources in relation to their δ15N signal.


Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA

Where published
Science of The Total Environment

Publication Identifiers
ISSN - 0048-9697

Publisher
Elsevier BV



Document Identifiers
URL - http://dx.doi.org/10.1016/j.scitotenv.2018.11.010
DOI - https://doi.org/10.1016/j.scitotenv.2018.11.010

Rankings
Web Of Science Q1 (2019) - 6.551 - ENVIRONMENTAL SCIENCES - SCIE
SCOPUS Q1 (2019) - 8.6 - Pollution
SCIMAGO Q1 (2019) - 1.661 - Pollution
SCOPUS Q1 (2019) - 8.6 - Pollution

Keywords
Biomonitoring Chlorophyll a fluorescence Nitrogen deposition Physiological response Source spatial distribution Xanthoria parietina