Nitrogen deposition

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The entry of reactive nitrogen compounds into bodies of water and soil via the air path is referred to as nitrogen deposition. The reactive nitrogen compounds include ammonia and nitrogen oxides .

background

In the course of industrialization , humans increasingly intervened in the natural nitrogen cycle . Agriculture and combustion processes in particular have introduced nitrogen compounds into the atmosphere which, in contrast to atmospheric nitrogen, are metabolized by plants and other organisms or react with the environment. These nitrogen compounds are called reactive nitrogen compounds.

The inputs of reactive nitrogen compounds into the environment contribute significantly to the loss of biodiversity . There is a positive correlation between the level of nitrogen deposition and the nitrogen content in plants.

In Germany, an average of 20 to 40 kilograms of nitrogen per hectare are entered by air as nitrogen deposition every year ; in approximately equal parts in reduced and oxidized form. According to the German Federal Environment Agency, the critical load limit for nitrogen emissions has been exceeded on 90 percent of the area in Germany. The situation is similar in Switzerland. The deposition rates range between less than 5 and more than 40 kilograms of nitrogen per hectare and year.

The spreading behavior of the various nitrogen compounds is different. Since the deposition rates of nitrogen oxides are seven times slower than those of ammonia, nitrogen oxides travel further distances before they are deposited.

Metrological recording

Since the nitrogen inputs take place in different forms (as gas or by means of dry or wet deposition ) and in different compounds, their measurement-related acquisition is very complex. Therefore, they are often recorded using bioindications . It is important that the organisms used do not use the nitrogen ingested for growth, but rather enrich it. This is the case with the mosses Pleurozium schreberi and Scleropodium purum . The leaf lichen Parmelia sulcata is also able to do this.

Individual evidence

  1. ↑ a b Ute Windisch: Possible uses of lichens in the biomonitoring of atmospheric reactive nitrogen inputs. In: Hazardous substances - cleanliness. Air . 77, No. 4, 2017, ISSN  0949-8036 , pp. 123-126.
  2. ↑ Advisory Council for Environmental Issues: Nitrogen: Strategies for solving an urgent environmental problem. Erich Schmidt Verlag, Berlin 2015, ISBN 978-3-503-16300-7 , p. 56.
  3. ↑ a b c d VDI 3959 sheet 1: 2008-12 Vegetation as an indicator for nitrogen inputs; Evaluation of nitrogen availability by Ellenberg indicator values ​​of forest ground vegetation (Vegetation as an indicator of nitrogen input; Assessment of nitrogen availability by Ellenberg indicator values ​​of forest ground vegetation). Beuth Verlag, Berlin, pp. 2–3.
  4. ↑ Advisory Council for Environmental Issues : Nitrogen: Strategies for solving an urgent environmental problem. Erich Schmidt Verlag, Berlin 2015, ISBN 978-3-503-16300-7 , p. 24.
  5. ↑ a b c VDI 3957 sheet 19: 2009-12 Biological measurement methods for determining and assessing the effects of air pollution (bioindication); Detection of regional nitrogen deposits with the deciduous moss Scleropodium purum and Pleurozium schreberi (Biological measurement procedures to determine and assess the effects of ambient air pollutants (bioindication); Detection of regional nitrogen depositions with the mosses Scleropodium purum and Pleurozium schreberi). Beuth Verlag, Berlin, p. 2.
  6. ↑ Federal Office for the Environment : Map Excessive Nitrogen Deposition , 2015.
  7. ↑ Federal Office for the Environment: Map nitrogen deposition , 2015.
  8. ↑ Advisory Council for Environmental Issues: Nitrogen: Strategies for solving an urgent environmental problem. Erich Schmidt Verlag, Berlin 2015, ISBN 978-3-503-16300-7 , p. 61.
  9. ↑ VDI 3957 sheet 18: 2015-12 Biological measurement methods for determining and assessing the effects of air pollution (biomonitoring); Detection of nitrogen accumulation in the leaf lichen Parmelia sulcata for the detection of ambient air pollutants (Biological measuring techniques for the determination and evaluation of effects of air pollutants (biomonitoring); Determination of nitrogen accumulation in the foliose lichen Parmelia sulcata detecting effects of ambient air pollutants). Beuth Verlag, Berlin, p. 3.