Peatlands Flashcards
definition of a peatland
terrestrial wetland ecosystems with waterlogged conditions that prevent plant material from fully decomposing
what exceeds deposition
the production of organic matter
3 types of peatlands
boreal, temperate and tropical
what is peat
sedentary accumulated material consisting of at least 30% mass of dead organic material
peat soils
sedentarily accumulated and have at least 30% organic matter over a depth of at least 45cm on undrained land, 30cm on drained land
peatland
geographical area where peat soil occurs and should cover a min. area of 1Ha for mapping purposes
how deep were irish peatlands before excavation
up to 12m
describe the structure of a peatland
no distinctive boundaries, gradually becomes peat
describe the formation of a peatland
organic matter accumulates and is buried, near continuous soil saturation, anaerobic conditions slow decomposition
what percentage of total soil carbon is in bogs
33%
what percentage of land surface area is covered by bogs
3%
in what period of the holocene were peatlands primarily formed
after the last glacial max., ice sheet retreat led to flooding in hollows and a wet landscape-> glacial lakes fill with veg…
how is sphagnum an effective peat forming material
sphagnum buildup causes water table to rise, when it dies, the higher water table prevents decay
what gas is released when the water table rises
small amount of methane
what gas is released when the water table falls
CO2
how much greater store of carbon is peatland versus amazon rainforest
deep peat is over 10 x greater store per hectare than amazon forest stores
why do peatlands emit some methane
small amount of decomposition
name 4 ecosystem services provided by peatlands
provisioning, cultural, regulating and supporting
by how much do irish peatlands grow each year
1mm
what percentage of Ireland is covered by peatland
21%
Are irish bogs rain or groundwater fed
rain fed
2 types of blanket bog
LLA (low level Atlantic) and HLM (high level Montaine)
how did blanket bogs form
early farmers cut down trees and farmed the soil, rain leached minerals to form iron pan, build up of waterlogged soils suitable for sphagnum mosses
how did raised bogs form
in a postglacial landscape, rushes at side of lakes die and accumulate , infilling the basin
paludiculture
wet land agriculture
what occurs when peat is forested
becomes more compacted as trees remove water from the bog
what type of peatland has natural trees
tropical
5 impacts of peat drainage
land degradation, biodiversity loss, increase of carbon loss via water, increased fire frequency, increased GHG emissions
three reasons why peatlands are drained
afforestation, agriculture, grasslands
what are palsa peatlands
permafrost peatlands, frozen
4 levels of permafrost frozenness as you travel south
continuous, discontinuous, sporadic, isolated
active layer of permafrost
layer that allows plants to grow, thaws out in summer
what is the consequence of the active layer of permafrost peatlands deepening
CO2 release
what is causing permafrost degradation
more temp change in northern latitudes due to warming - impacted more. increase in rainfall melts ice
