Total Nitrogen Content and δ¹⁵N Signatures in Moss Tissue: Indicative Value for Nitrogen Deposition Patterns and Source Allocation on a Nationwide Scale

Abstract

To evaluate a new N-monitoring program in the framework of the UN-ECE ICP-Vegetation program using mosses as bioindicators, 490 moss samples were collected at 220 sites in Austria and analyzed for total N (N content) and delta(15)N signatures. Within-site variability of N content and delta(15)N signatures was tested for the first time on a large scale and was extremely low compared to between-site variability. N content in moss tissue ranged between 0.76% and 1.99% and delta(15)N signatures between -10.04 and -2.45. Altitude was significantly correlated with N content (P=0.021) and delta(15)N signatures (P<0.001). When comparing moss data to deposition data from 35 measurement sites, significant correlations between N content and N deposition (P=0.014) were found. Increasing delta(15)N signatures provided evidence for a change in N source and its respective isotopic composition with altitude, e.g., due to long-distance transport of reactive N or as a result of changes in the wetdry deposition ratio. Our study underlines that N deposition can generally be estimated by N content in mosses on a large scale, but that this approach has certain limitations, especially in areas with large differences in altitude and precipitation.

First Europe-wide correlation analysis identifying factors best explaining the total nitrogen concentration in mosses

“…This study reveals that mosses can potentially be used as biomonitors of total This study may be regarded as a cross validation of European moss data and EMEP model data for N, but is complicated by both potential limitations in the of mosses as monitors of atmospheric N deposition (Harmens et al, 2008b;Zechmeister et al, 2008) and the uncertainties in the modelled nitrogen deposition, including uncertainties in emissions (Lieven et al, 2009). The moss technique provides a tool for validating the spatial pattern for modelled EMEP air concentrations and depositions of nitrogen compounds at a higher spatial resolution than can be achieved using the EMEP measurement stations throughout Europe.…”

“…Carpet-forming ectohydric mosses might potentially be used as biomonitors of atmospheric N deposition as well (Pitcairn et al, 1995(Pitcairn et al, , 2006Poikolainen et al 2009;Salemaa et al, 2008;Solga et al, 2005;Zechmeister et al 2008). A pilot-study in Scandinavian countries showed a strong linear relationship between the total N concentration in mosses and EMEP-modelled atmospheric N deposition rates (Harmens et al, 2005).…”

Variation in foliar δ15N among oriental oak (Quercus variabilis) stands over eastern China: Patterns and interactions

“…Across a gradient of nitrogen deposition in northeastern U.S., Pardo et al (2007aPardo et al ( , 2007b showed that foliar δ 15 N was strongly correlated with N deposition, and was also positively correlated with net nitrification potential and negatively correlated with soil C:N ratio. In this sense, plant foliar δ 15 N could be used as a useful indicator in reflecting the response of plants to anthropogenic N deposition in an area (Emmett et al, 1998;Garten and Hanson, 1990;Koopmans et al, 1997;Liu et al, 2007;Pardo et al, 2007a;Sah, 2005;Zechmeister et al, 2008). Meanwhile, it might be used to evaluate the effect of atmospheric N deposition and nitrogen saturation in forest ecosystems.…”

Stable nitrogen isotopes (d15N) in thalli of arid vagrant lichen Xanthoparmelia camtschadalis across an altitudinal gradient of the Khangai Plateau of Mongolia

“…It should be noted, however, that the lowest sampling point was located on the territory of a city with a large population, that is, the region was enriched in nitrogen containing compounds. In Aus tria, the studies of d 15 N values in tissues of a few moss species, which were collected from 220 sampling points that were located pretty much evenly on the ter ritory of the country (2.5 sampling points per 1000 km 2 ), demonstrated the highly significant posi tive correlation between d 15 N values in moss tissues and the sampling point altitude [54]. To summarize, mosses, which, as well as lichens, belong to thallus containing and poikilohydric organisms, demonstrate a different dependence of d 15 N values on the habitat altitude compared to the X. camtschadalis vagrant lichen in the Khangai.…”