Fens

Question 1

Defining characteristics

Answer 1

• > 30 cm of peat

* Geogenous: recieves water other than precipitation

Question 2

Hydrology

Answer 2

•Inputs from P, Si, and Gi

•Hydrological setting is variable
–Flat,
–Sloping,
–Floodplains, and
–Groundwater discharge/recharge

see slide 36

Question 3

Biogeochemistry

Answer 3

•Extremely variable:
–Extreme-rich fen (pH 7-8.5)
–Rich fen (pH 7-5.5)
–Poor fen (pH 5.7-5.5)

•Depends on:
–Groundwater flow rate
–Chemistry
–Presence of Sphagnum
–Build up of organic acids as decomposition decreases

Question 4

Vegetation

Answer 4

• Sedges (Carex)
• Rushes (Juncus)
• Willows (Salix)
• Brown mosses