Wetlands, Peat, and Tundra Part 3 Flashcards
Oligotrophic= ___ fertility
Mesotrophic= ___ fertility
Eutrophic= ___ fertility
low
medium
high
fens have a ___ pH, bogs have a ___ pH (ie ___)
high
low (acidic)
Wetland formation is a function of:
1
2
3
4
5
- climate
- geomorphology (landform and soil parent material)
- hydrology (internal/external drainage)
- chemistry of water/ soils
- biology (fauna and flora)
t/f
swamps must be wet all year long
false
swamps are forested wetlands, so they may not be wet all year long because trees need dry-ish conditions to grow
swamps are ___ wetlands/ peatlands, associated with lakes and ____, and periodically inundated by ____
forested
waterways
water
Why are marshes and swamps usually found further south than peatlands?
because decomp is temp dependent
- marshes/ swamps are on well decomposed mineral soil
Marshes are adjacent to ____, so they have shallow water whose levels ____
waterways
fluctuate
Which type of wetland is described:
- little accumulation of peat
- high productivity
- high decomp
- herbaceous vegetation
marshes
t/f
marshes can be coastal (marine) or freshwater
true
Graphs of land and ocean temp departures from average tell us that ___ systems are getting especially warmer
northern
Mean annual air temp (MAAT) is determined solely by ____ ____, and mean annual ground temp (MAGT) is key to controlling ___ thickness
MAAT ___ MAGT
prevailing climate
permafrost
impacts
Is the ground below the permafrost (very deep) impacted by global warming?
no
geothermal heating causes the ground below permafrost to be >0 degrees C (always unfrozen, not impacted by global warming)
typically, the further north you go, the ___ the active layer becomes
Also, permafrost becomes more ___
thinner
continuous
___ have a shallow active layer due to the insulating properties of peat, which dries in summer
bogs
fens are wet, which ___ the depth of the summer thaw (___ active layer)
enhance
deeper
sandy areas (eg beach ridges)= the ground can easily ___ in summer, resulting in a ___ active layer
warm
deep
Tundra polygons are caused by the earth ___ with __-__ cycles
cracking
freeze-thaw
How do ice wedges form?
frozen winter ground cracks, and fills with water in spring
- water pushes soil up, and when it freezes, expands the crack more
- more water enters the expanded crack, freezes, expands, ….
In a high-centered ice-wedge polygon, the ice wedges have ____ because the water flows ___
disappeared
downhill
In a low-centered ice-wedge polygon, ice-wedges are ___/___ because water is flowing ___ them
forming/ present
into
What causes a ‘drunken forest’?
as permafrost melts, trees slump into bogs etc because they’re no longer supported by the permafrost underneath
_____ ____= a shallow body of freshwater that’s formed in a depression by meltwater from thawing permafrost
- why does the depression form?
thermokarst lake
- depression often produced by collapse of ground levels associated with permafrost thaw
ebullition=
bubbling of methane in a thermokarst lake from decomposition
How does ebullition occur?
permafrost thaws
- trees fall into thermokarst lake b/c land slumps
- organic matter (trees) decompose at the bottom of the lake
- methane bubbles form from this decomp, and bubble up to the surface
Why are thaw slumps a problem from humans?
our houses etc are on this land- they will be ruined
also pipes
Why is coastal erosion getting worse?
sea level is rising –> reaching more land to erode
longer open water periods= more time to erode
t/f
peat fires can burn underground for a very long time
true
hard to monitor/ put out
what roles do wetlands play in boreal ecosystems?
- many acid-sensitive lakes are present in boreal regions of alberta (where % wetland cover is high)
- therefore lake naturally acidified by peatland outflows
- peatlands attenuate water runoff and alter water chemistry
- peatlands accumulate C on the long-term (important global C sink)
