Lecture 5- Peatlands Flashcards
What is peat?
Accumulation of poorly decomposed organic matter
How does peat form?
Peat forms when decomposition is slower than decomposition usually due to anaerobic conditions
What is a key moss species?
Sphagnum moss species
Describe some characteristics of Sphagnum
-Huge water holding capacity
-Have highline cells, barrel shaped
-Can expand and hold more water
-Hold 20X its dry weight in water
-Can grow in more open areas because more water
Peat is a _____ genus adapted to holding a lot of water
Diverse
Peat has no vascular tissue so it cant ______
Bring up water from the ground
_____ have no differentiation in the layers while ____ have differentiation of soil layers
-Wetlands
-Peatlands
Can the O layer of peatland soils be thick?
Yes, can range from a few cm to m thick, depends on the accumulation of organic matter
What is a peatland?
An ecosystem where > 30-40cm of peat has formed (bulk of soil layer)
Does peat accumulation fast or slow?
Accumulates very slowly
True of False? Decomposition occurs very fast in peatlands
False (Decomposition is very slow = anaerobic conditions)
Describe activity in peatlands
Water logged= less oxygen and less microbial activity= accumulation of organic dead matter that isnt decomposing (accumulation of dead moss within new moss)
What country has the most amount of peatlands?
Canada because of the Canadian shield
Why are peatlands so prevalent in the north?
-Permafrost restricts movement of water
-Flat terrain can reduce water flow
-Short summers and cold temperatures reduce rates of decomposition
-Not really any flowing water
What are the three conditions that cause a peatland to form?
- Annual precipitation must be greater than 500 mm
- Annual biotemperature can not be too hot
- There must be a positive water balance in the area
What are some functions of peatlands?
-Regulation of global climate, catchment hydrology, soil conditions
-Used as a habitat
-Energy generation
-Global carbon sink (when it dies, none of the carbon gets released so the organic layer stores so much carbon)
-Humus and organic fertilizer
-Used to dry malted barley
-Can regulate the water
How are peatlands formed?
Formed via terrestrialization and paludification
What occurs during terrestrialization?
-As decomposition declines, ponds fill overtime
-Emergent vegetation grows along periphery
-Sphagnum colonizes and peat accumulates
-Floating mats form in center
-Wetland overtime it dries out, decline in decomposition, get accumulation of organic matter = get more shallow overtime
Can terrestrialization and paludification occur at the same time?
Can both happen at the same time or happen on its own or one can trigger the other
Describe paludification
-As peat filled wetland, it begins to colonize adjacent forests
-Colonization continues as peatland spreads
-Peat continues to accumulate into a dome
-The peat spreading out to adjacent forests (outward)
What factors contribute to peatland succession?
-Spectrum of peat accumulation
-How closely the peatland is accessing water
-How much water is present and how much is flowing
-Push the peatland further and further from the ground water until its no longer accessing the water at all
Describe water flow in fens
-Peatland which is influenced b water from outside its own limits
-Surface water flow from adjacent wetlands
-Ground water flow
-Hydrology influenced by water flowing in and grond water
What type of nutrient loading does fens have?
-Higher nutrient loading because of water flow, tend to have higher nutrient availability and more productive ecosystem
-More minerals coming in making pH a little higher
Do fens have high plant diversity?
Yes
