Nitrogen Cycle

It is a toxic gas that has adverse health effects both in the long term (chronic) and short term (acute).

Data from Europe suggested that long-term concentrations of nitrogen dioxide or nitrogen oxides (NO) were associated with an increased risk of all-cause mortality.

Nitrogen dioxide is strongly related to particulate matter.

https://www.epa.vic.gov.au/for-community/environmental-information/air-quality/nitrogen-dioxide-in-the-air

NO₂ and NH₃ - Reactive nitrogen contributes to particle mass and to the adverse health effects caused by the PM.

NO₂ and NH₃ - Reactive nitrogen contributes to particle mass and to the adverse health effects caused by the PM.

https://www.lung.org/research/sota/health-risks

Atmospheric ammonium is absorbed by the leaves of plants. More precisely through the stomata, where gas exchanges take place.

Atmospheric ammonium is absorbed by the leaves of plants. More precisely through the stomata, where gas exchanges take place.

Before reaching the leaf, the pollutant will first have to pass through the “boundary layer”.

Lichens are very affected by atmospheric pollution because they not have a impermeable cuticle.

Lichens and bryophytes are an important part of the ecosystem integrity.

https://www.irishtimes.com/news/science/the-trouble-with-ammonia-1.3721098

Ammonia acts as a macro-nutrient and at low exposure levels plants respond by increasing their biomass production.

Because plant growth is often limited by the supply of nutrient nitrogen, and so any increases in growth may lead to negative effects on community composition.

The fertilisation effect can at higher exposure levels lead to secondary long-term adverse effects including increased susceptibility to abiotic (drought, frost) and biotic stresses.

Today ozone is considered to be the most important gaseous pollutant causing effects on vegetation.

Besides visible injuries on leafs and needles, ozone also causes premature leaf loss, reduced photosynthesis and reduced leaf, root, and total dry weights in sensitive plant species.

https://extension.umd.edu/learn/air-pollution-effects-vegetables

Today ozone is considered to be the most important gaseous pollutant causing effects on vegetation.

Besides visible injuries on leafs and needles, ozone also causes premature leaf loss, reduced photosynthesis and reduced leaf, root, and total dry weights in sensitive plant species.

This leads to significant decrease in productivity of some agricultural crops and to reduced forest production.

Effects of ozone on vegetation: from plant cells to ecosystems. [Source: © J.P. Garrec]

The regulatory level is usually met for public water supplies, which are routinely monitored.

In the EU, noncompliance to the nitrate or nitrite standards in large public supplies is reported regularly but rarely exceeds 􏰃% of the sample population.

Bryan, Nathan S., et Hans van Grinsven. « The Role of Nitrate in Human Health ». In Advances in Agronomy, 119:153‐82. Elsevier, 2013.https://www.sciencedirect.com/science/article/abs/pii/B9780124072473000032?via%3Dihub

Nitrate itself is generally considered to be harmless at low concentrations.

Nitrite, on the other hand, is reactive especially in the acid environment of the stomach where it can nitrosate other molecules including proteins, amines and amides.

• Is one of the most common alterations of continental and marine waters.

• Result in an exacerbated productivity of aquatic ecosystems due to an excessive nutrient inputs.

Factors controlling eutrophication can be summed up as a combination of some or all of the following interacting factors:

• An excess of nutrients

• A long water residence time

• A sufficient amount of light

• A favourable temperature

Fig. Functional linkages between hydrology, anthropogenic nutrient inputs, eutrophication (phytoplankton blooms), and hypoxia/anoxia

in estuarine and coastal aquatic ecosystems.

Paerl, Hans W. « Assessing and Managing Nutrient-Enhanced Eutrophication in Estuarine and Coastal Waters: Interactive Effects of Human and Climatic Perturbations ». Ecological Engineering 26, no 1 (janvier 2006): 40‐54.

1. The increase in nutrients leads to a strong increase in primary productivity.

2. The new limiting factor becomes light.

3. The light penetration decreasing by self-shading as the biomass produced increases.

4. Development of more competitive species, which affects a change in primary producer communities, which changes the ecosystem and affects biodiversity.

https://www.unenvironment.org/nowpap/what-we-do/prevent-and-reduce-pollution/eutrophication

• A natural eutrophication phenomenon.

The difference between natural and anthropogenic eutrophication is time.

• the effects of soil compaction.

https://civilblog.org/

• the effects of erosion.

  1. Loss of productivity and sediment accumulating due to erosion sometimes can be seen in the same field as showing in this photo.

  2. Rain enhances the translocation of soil through the process of splashing. Individual raindrops detach soil aggregates and redeposit particles. The dispersed particles may then plug soil pores, reducing water intake. Once the soil dries, these particles develop into a crust at the soil surface and runoff is further increased.

  https://wiki.ubc.ca/

• the effects of salinisation.

  High salt concentrations inhibit biological nitrogen transformations in soil, as well as nitrogen fixing capacity by legumes.

  https://www.quora.com/

• the effects of soils contamination.

  https://www.worldatlas.com/

• the effect of organic matter decline.

  Figure. The vicious cycle of depletion in soil organic matter-decline in

  crop yield-food insecurity-soil

  Vicente Vicente, José. « Soil organic carbon sequestration in Andalusian olive groves: effect of the managements on soil organic carbon dynamics », 2017.