Quantitative biomonitoring of nitrogen deposition with TONIS (Total N Input Biomonitoring System)

- A new suitable biomonitoring technique is presented to determine N deposition rates relating to low-growing vegetation on nutrient-poor sites.
- TONIS combines the advantages of biomonitoring and technical measurements.
- The results of 6 exposures between 2012 and 2016 are feasible compared to technical measurements and modelled data.

Monitoring of air pollutants is an important instrument to detect threats and to observe temporal trends of emissions. Determining the spatial distribution of oxidized and reduced N species via modelling requires sufficient knowledge about innumerous small sources from traffic, settlements and agriculture. Empirical studies are required to validate the model data but measurements of the total N deposition (e.g. micrometeorological measurements) are very expensive.Against this background, the TONIS, a new suitable technique which combines a biomonitoring with plants and technical measurements was developed. During 6 exposures between 2012 and 2016 at different polluted sites in Northwest Germany, TONIS accumulated between 17 and 25 kg N ha-1 yr−1t. The results are feasible compared to simultaneously measured NH3 and NO2 concentration and bulk N deposition. At one site within a peat bog the accumulated N in TONIS was found to be in the range of total N deposition derived from a micrometeorological approach.

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