Peat Bog Flashcards
What features do all bogs worldwide share in common?(3)
- usually develop where drainage blocked
- cushion like vegetation
- accumulation of peat **
Almost all water comes from?
precipitation
Bogs are high or low in key nutrients?
low
Bogs occur in most __ areas but best developed in ___ areas of North America, Europe and Asia.
- humid(areas of high precipitation ,,,,
- northern forest
Formation of Peat Bogs:
- Two ways it can begin..
- terrestrialization
2. paludification
Formation of Peat Bogs:
- terrestrialization?
- freshwater lakes and ponds fill with sediments, organic deposits or peat
Formation of Peat Bogs:
- paludification?
- sphagnum blankets dry land and prevents water from leaving the surface
Peat is composed of?
- decaying organic matter (primarily plants)
Formation of Peat Bogs:
- common first steps?
- lake or pond fills from edges and trees become established
Bog Formation - Terrestrialization:
step 1?
- open water fills with sediment
Bog Formation - Terrestrialization:
step 2?
- litoral flora advance toward the centre and create swamp conditions with standing water among vegetation
Bog Formation - Terrestrialization:
step 3?
- debris accumulates and sediments reach the surface with very little standing water= a marsh
Two end results can happen for a forming bog…?
- raised bog (sphagnum on top)
- dry bog
* *depends on the local climate such as precipitation
Bog Formation:
- wetland will develop into ____ if dry location or a ____ if its moist and foggy.
- terrestrial vegetation (dry bog)
- raised bog
Bog Formation
-Peat accumulation takes place only as long as what?
-rate of growth > decay
Bog Formation
- Ability of anaerobic bacteria to decay organic material is reduced by?
- a lack of oxygen from water logging
* *also high pH and lack of nutrients aid in process
Raised Bog Formation:
- Raised bogs form from remains of?
- mosses of the genus sphagnum in areas of high rainfall or persistent fog
- *sphagnum can absorb 15-20 x its own weight in water
Raised Bog Formation:
- when will it cease to develop?
when raised far enough that it:
- is not totally water soaked or
- if the climate becomes drier
* *raised bogs may form in slight depressions on flat ground or on slopes
Little Decay of Organic Matter:
- peat accumulating in raised bogs is ___ and ___. As a result the organic matter may not readily decay.
- acidic
anoxic (Low oxygen)
Little Decay of Organic Matter:
- Low decomposition results from? (4)
- low temp
- water logged soil
- low oxygen
- low nutrients
Thickness of the bog is proportional to?
age
- *remains of previous biota buried as bog thickens…
- most useful ecological record comes from pollen and spores from plant species preserved in bog
Reconstruction of plant communities:
- insight into past ___ from plant temperature and rainfall preferences.
climate
Reconstruction of plant communities:
- ages of different layers using
carbon dating
Reconstruction of plant communities:
- can reconstruct local conditions for about the last?
10,000 years when local peat bogs started to form at the end of the last ice age.