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.
Harsh Living Conditions for Plants
- peculiar physical characteristics of raised bogs such as?
- rain water provides main source of moisture, resulting in low nutrient supply
- referred to as ombrotrophic meaning rain fed
- Ca, N and P are in very low []
Harsh Living Conditions for Plants
- Only plants adapted to low___ can survive
low nutrient availability
*even these are often stunted
Harsh Living Conditions for Plants
-plants adapted to conniptions :?
- those typical of subarctic areas and of nutrient poor tropical rain forests… (thrive in areas where other plants cannot bc in other areas these plants would be out grown …)
Harsh Living Conditions for Plants
ex: subarctic plants?
- black spruce, cotton grass, labrador tea etc
Adaptation to low Nutrient Levels? (7)
- being carnivorous ( pitcher plant ex) …insectivorous plants that trap insects to supplement their nutrients
- nutrient conservation: retain green leaves through winter (ex spruce)
- symbiotic association: with fungi or nitrogen fixing bacteria that obtain nitrogen directly from the air.
- reduced need for nutrients ex black apples
- nutrient translocation to overwintering parts of the plant before leaves dropped in the fall.
- far reaching root systems to capture nutrients in upper layer (many plants)
(most plants have roots that go in mineral layer therefore as bog grows it is seared from this layer that provides P and N…solution spread roots laterally - Scleromorphic leaves: firm and dry leaves (e.g. leather leaf) prevents herbivores from eating them
Adaptations to unstable substrate?
- dense entwining root systems or rhizomes (shrubs..sedges )
- short growth form (black spruce..tamarack)
Water logging:
- Results in low oxygen concentrations
- adaptations to deal with this?
- new roots each year in upper aerated layer of peat (e.g. sedges)
- adventitious roots: from trunks and stems (black spruce…willow etc)
- air sacs: and large spaces between cells to store air… i.e. sphagnum …aerenchyma
- reduced need for oxygen when submerged (some aquatic plants)
- oxygen gained directly from surrounding water (i.e. bladderworts)
Peat Mining and Environmental Considerations:
- most extensive concentration in __across northern ON, through central MB, and SK, northern NB and Mackenzie river valley NWT.
belt running
Animals in bog?
- low primary productivity–> generate little plant biomass
- few bog specialistsL
1. inverts
2. amphibians
3. birds (can exploit areas) - *herbs avoid area
- *low pH and lack of Ca = mollusc will not dow well here
Peat Mining and Environmental Considerations:
- 5 wetland classes in Canadian classification system?
- bog
- fen
- swamp
4 . marsh - shallow open waters
Peat Mining and Environmental Considerations:
- bog characteristics?
- raised or domed surface, high water table, low pH , lack of nutrients and presence of sphagnum
Peat Mining and Environmental Considerations:
- most horticultural peat produced in Canada comes from?
bogs
Peat: Desirable properties?
high water retention
low density
high resistance to decomposition
low heat conductivity and high porosity
Peat is used for?
- fuel, fertilizers, cattle food and textiles…horticultural industry
QC and NB = ~ _% of total, balance from western provinces
75
Peat Mining phases?
- Land Prep
- reduction of moisture content from 90 to 80%using draining ditches
-surface thens table enough to support equipment
2.a) Milling
- surface layer harrowed to expose it to wind and sunshine
- left until moisture = 50%
- then collected using large vacuums
OR - b) block cutting
- peat mechanically cut and stacked left to dry
- after several days of drying ..turned fro further drying and subsequent collection bagging
Environmental Impacts of Peat Mining:
1. Peatland drainage?
- may change quality of receiving streams, affecting downstream organisms
- impacts can be reduced by sedimentation ponds or directing drainage waters to areas where they can be filtered
Environmental Impacts of Peat Mining:
2. Peat dust
under dry and windy conditions fugitive peat can be transported to uninhibited areas…
- reducing dust requires air filters on vacuum mining…equipment and overing peat stockpiles in labs
Environmental Impacts of Peat Mining:
3. Site restoration?
- NB policy= sustainable development which requires abandoned sites be returned to productive use
- in most canses, sites abounded in the way…that favours return of wet land flora…the return of wetland flora and fauna
- can’t be returned to original conditions …efforts are being made to develop techniques to restore peat water
- Climate change
- carbon storage is sig
- about 25% of all plant and soil carbon
- extraction and draining and fires all remove peat..therefore carbon from storage and put it back up in circulation
