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☔️ Water series: Interactions of flora with water and climate: Difference between revisions
☔️ Water series: Interactions of flora with water and climate (view source)
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===Wetlands=== | ===Wetlands=== | ||
Wetlands are almost constantly saturated water, so this water stays available for nearby valleys and prairies by leaking through groundwater or slowly streaming in rivers. Hence, this water benefits as much wetlands ecosystems as fields of local farmers<ref>Still, the water saturation often drives farmers to drain their soil to grow crops.</ref>. Considered useless and dangerous in the ancient times<ref>Marshes and swamps were considered as disease reserves, and unsuitable for most agricultural system, because unworkable.</ref>, wetlands used to be massively drained to obtain more agricultural lands; but wetlands are today recognised as the most important type of ecosystems to preserve, protect and restore. Why is it so? | Wetlands are almost constantly saturated water, so this water stays available for nearby valleys and prairies by leaking through groundwater or slowly streaming in rivers. Hence, this water benefits as much wetlands ecosystems as fields of local farmers<ref>Still, the water saturation often drives farmers to drain their soil to grow crops.</ref>. Considered useless and dangerous in the ancient times<ref>Marshes and swamps were considered as disease reserves, and unsuitable for most agricultural system, because unworkable.</ref>, wetlands used to be massively drained to obtain more agricultural lands; but wetlands are today recognised as the most important type of ecosystems to preserve, protect and restore. Why is it so?<ref>In any given ecosystem, appart from tropical rainforest, carbon stocks are significantly higher in the soil than in plants and animals. | ||
source: https://fr.wikipedia.org/wiki/Fichier:IPCCStockCarboneSolsV%C3%A9g%C3%A9tationFr.jpg</ref> | |||
<ul><li>The first reason lies in plain sight: they are considered the most biologically diverse of all ecosystems.<ref>From marine and coastal wetlands like salt marshes, sea cliffs, mangroves and lagons; to inland wetlands like rivers, lakes, seasonally flooded prairies, ponds and meadows.</ref> | <ul><li>The first reason lies in plain sight: they are considered the most biologically diverse of all ecosystems.<ref>From marine and coastal wetlands like salt marshes, sea cliffs, mangroves and lagons; to inland wetlands like rivers, lakes, seasonally flooded prairies, ponds and meadows.</ref> | ||
</li><li>The second reason is the ability of some wetlands to filter water by retaining nutrients and trap heavy metals that can be processed by some plants, thus limiting the pollution of rivers and groundwater. | </li><li>The second reason is the ability of some wetlands to filter water by retaining nutrients and trap heavy metals that can be processed by some plants, thus limiting the pollution of rivers and groundwater. | ||
</li><li>The third and last reason is the ability of wetland to store atmospheric CO2 in the form of vegetation and soil.</li></ul | </li><li>The third and last reason is the ability of wetland to store atmospheric CO2 in the form of vegetation and soil.</li></ul> | ||
Among all types of soils that can be found in wetlands, peat soils<ref>Peat can be used as a fuel, and is similar to coal an oil, as it is old undecayed organic matter, but younger thus unfossilised.</ref> are the most effective at storing the excess of atmospheric carbon (for as long as they don’t dry or burn). When plants that extracted atmospheric carbon from the air die, their organic matter composed of carbon is trapped in the water under anaerobic conditions that allows the annual rate of biomass production (plant growth) to be greater than the rate of decomposition.<ref name="wikisource" /> This means that the accumulation of dead plants in the soil is so fast that it grows faster than plants and soil animals can process it. Thus, a humus depth of a few meter can form, when most soils only accumulate a few decimetres of humus.<ref>Humus is the top layer of the soil, which is made of decaying organic matter consumed by decomposers. It is vital for plants to grow, but also subject to erosion.</ref> Water keeps this “unused” carbonic organic matter in a state of stability that makes it such an efficient carbon sink.<ref name="wikisource" /> | Among all types of soils that can be found in wetlands, peat soils<ref>Peat can be used as a fuel, and is similar to coal an oil, as it is old undecayed organic matter, but younger thus unfossilised.</ref> are the most effective at storing the excess of atmospheric carbon (for as long as they don’t dry or burn). When plants that extracted atmospheric carbon from the air die, their organic matter composed of carbon is trapped in the water under anaerobic conditions that allows the annual rate of biomass production (plant growth) to be greater than the rate of decomposition.<ref name="wikisource" /> This means that the accumulation of dead plants in the soil is so fast that it grows faster than plants and soil animals can process it. Thus, a humus depth of a few meter can form, when most soils only accumulate a few decimetres of humus.<ref>Humus is the top layer of the soil, which is made of decaying organic matter consumed by decomposers. It is vital for plants to grow, but also subject to erosion.</ref> Water keeps this “unused” carbonic organic matter in a state of stability that makes it such an efficient carbon sink.<ref name="wikisource" /> | ||