A few years ago the study of the effects of atmospheric deposition on forest ecosystems reached beyond the scientific sphere and the term “acid rain” was coined. This problem, which ignores frontiers, happens because, due to the burning of fossil fuels, the amount of sulphur and nitrogen oxides in the atmosphere is greater than that derived from natural processes.
Oxides, in the presence of water vapour and under the oxido-reduction conditions present in the atmosphere, produce acids that are deposited, amongst other places, on the forest biomass. Also, intensification in the cattle sector, together with stabling and grouping together of herds, have given rise to the concentration of ammonia emissions in certain zones. This compound, deposited close to the sources of emission, is able to react with the acidic ions deposited at the same time. Subsequently, certain bacteria are capable of oxidising the compound, thus forming nitrate and liberating protons that acidify the soil.
Amongst the effects of the deposition of these compounds on the forest mass are the well-known nutrition disorders of the same. One classic effect is that of cation deficit (particularly magnesium) due to the washing both of the forest canopy and the soil produced by these together with anions (sulphates and nitrates). This problem is not very common in forest ecosystems close to the sea given that, in these conditions, the uptake of magnesium with precipitation is high. Another consequence is what is known as the eutrofization of terrestrial ecosystems due to the increase in nitrogen availability (saturation) in systems where historically this element has been the limiting factor in productivity.
Irati Kortabitarte | alfa
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