Cette leçon contient 12 diapositives, avec diapositives de texte et 1 vidéo.
La durée de la leçon est: 45 min
Éléments de cette leçon
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
La durée de la leçon est: 45 min
