4.5 The peat landscape

4.5 The peat landscape
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Slide 1: Diapositive
AardrijkskundeMiddelbare schoolhavo, vwoLeerjaar 2

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4.5 The peat landscape

Slide 1 - Diapositive

Aims
  • Explain the differences between fen and bog.
  • Explain how people influenced the peat landscape.  

Slide 2 - Diapositive

Peat landscape
Peat =  Dead plants, fallen in water and piled up with other plants; after a long time, a layer of dead plants is formed this way.

Fen = Type of peat that is formed under water.

Bog =  A type of peat that is formed by dead layers of sphagnum.
Spaghnum

Slide 3 - Diapositive

Slide 4 - Vidéo

Dutch peat landscape
Peat formation and degradation in The Netherlands up to the Middle Ages (BP = Before Present). In the late Middle Ages people started to drain and reclaim peat soils.

Slide 5 - Diapositive

Do you see the remains of plants in the peat?
The formation of fen and bog.

Slide 6 - Diapositive

Extracting fen. The peat is dug out and put to dry on the legakkers.
Cutting bog in a northern part of the Netherlands, early 20th century. 

Slide 7 - Diapositive

Legakkers and petgaten in a fen landscape.
Legakker = Small strips of land where fen was put to dry.
Petgaten =  Water that remains after fen is extracted.
This pattern of water and land changed through time, because storms caused waves which eroded the remaining soft peat soil of the legakkers. This resulted in expanding lakes, like the Nieuwkoopse Plassen. Some of these lakes were reclaimed and became polders. Nowadays the remaining lakes are excellent places for recreation and nature, close to the Randstad.

Slide 8 - Diapositive

Subsidence = The motion of the ground as it shifts downward.

Slide 9 - Diapositive

Double trouble!

Slide 10 - Diapositive

The global distribution of peatlands. 

Slide 11 - Diapositive

Homework
2HT:
Monday 15 April, 7th hour: Read 4.5 and do ex. 1 to 3 and 5 to 9

2VT:
Monday 15 April, 3rd hour: Read 4.5 and do ex. 1 to 3 and 5 to 10

Slide 12 - Diapositive