Category FAQs Search : Ecosystem
Question: What is the characteristics of peatland geochemistry?
Answer: The development and stability of peatlands are determined by their hydrological setting and the soil’s
high water content. It is difficult to establish a simple mire classification system that can accommodate
both the flow characteristics and the chemistry of peatland waters. Bog peatlands are generally
nutrient-poor and fen peatlands are typically richer in nutrients. However, these different terms relate
only to the source of water and do not explicitly define a peatland’s chemical, nutrient or ecological
status. Indeed, there are many fens with low levels of nutrients in areas where the substrate material is
mineral-poor and groundwater flow is limited. This limited throughflow is often the direct result of the
slow hydraulic conductivity of the peat itself.
The diversity of peatlands can be seen in nearly all peat water chemistry parameters, including pH,
nutrient content, base richness and salinity. Peatland diversity is also reflected by integrated parameters,
such as vegetation (Wheeler and Proctor, 2000). Peatlands are also characterized by special redox2
conditions, which directly control the availability of nutrients, the presence of toxic metal species
and GHG production (Shotyk, 1988). Additionally, differences in physical characteristics contribute
to peatland diversity (e.g. depth of the water table, the temporal stability of water supply and the
stability of snow cover in winter). These features are often indicted by differences in microsites or
microstructural characteristics (Økland et al., 2001).
Water chemistry can reveal the connectedness of the peatland to groundwater or nearby mineral
systems. For example, the presence of calcium and bicarbonate can be used as an indicator of the inflow
of deep groundwater. Together with pH, base cations (like calcium, magnesium, sodium and potassium)
are often used to categorize peatlands into bogs, poor fens, moderately rich fens and rich fens (as
reviewed in Bourbonniere, 2009). Nutrient gradients that recognize the elements that limit plant growth
are also used to characterize and distinguish different peatland types (Bridgham et al., 1996).
The export of DOC from peatlands is a key part of the carbon cycle and has important implications for
downstream water chemistry. Drainage, which mobilizes old carbon from deeper depths in the peat
profile, is expect to increase DOC export and lead to higher concentrations of CO2
in the atmosphere.
Understanding how DOM reacts to land use and climate changes can improve predictions about the
solubility and transport of metals and organic pollutants, which are closely linked to DOM dynamics
(Kalbitz and Wennrich, 1998).
(Source: MITIGATION OF CLIMATE CHANGE IN AGRICULTURE SERIES 9 - Climate-responsible peatlands management (Food and Agriculture of United Nations), 29 Jan 2021)
Source Link: http://www.fao.org/3/a-i4029e.pdf