10 Mg L
À1 , Mg
2+
> 10 Mg L
À1 , PO 4
3À
> 4 Mg L
À1 ). SO 4
2À showed an increasing
tendency from the top to the bottom peat layer because of sulfuric acid contamination after pyrite oxidation in the mineral sediment layer below the peat layer. The
SO 4
2À concentration in peat pore water at the bottom of the peat layer depends on the
content of pyrite in the mineral sediments below the peat layer, and it increased
according to the proximity to the coastline.
1.6 Adaptation to Oxygen-Limited Conditions
Biomass productivity is extremely high in tropical peatlands compared with that in
tropical mineral soil. However, as oxygen and nutrients are essential elements for
plant growth, plant growth strategies in tropical peatlands are interesting. In particular, oxygen is limited by the high groundwater level because oxygen solubility in
water is very low, and nutrient content is also limited by the low nutrient concentrations in peat and peat water.
Two strategies for oxygen absorption are observed in native peatland forests
(Fig. 1.17):
Tumih
Combretocarpus
rotundatus
Sago
(Metroxylon sagu)
Aerial Roots
Mound Roots
Jelutong
(Dyera costulata)
Fig. 1.17 Aerial roots and mound roots for oxygen and nutrient absorption in a native peatland
ecosystem. Mound roots exist in mounds and have several morphology types such as lateral roots,
aerial roots, mangrove-like roots, and so on
26
M. Osaki et al.
À1 , Mg
2+
> 10 Mg L
À1 , PO 4
3À
> 4 Mg L
À1 ). SO 4
2À showed an increasing
tendency from the top to the bottom peat layer because of sulfuric acid contamination after pyrite oxidation in the mineral sediment layer below the peat layer. The
SO 4
2À concentration in peat pore water at the bottom of the peat layer depends on the
content of pyrite in the mineral sediments below the peat layer, and it increased
according to the proximity to the coastline.
1.6 Adaptation to Oxygen-Limited Conditions
Biomass productivity is extremely high in tropical peatlands compared with that in
tropical mineral soil. However, as oxygen and nutrients are essential elements for
plant growth, plant growth strategies in tropical peatlands are interesting. In particular, oxygen is limited by the high groundwater level because oxygen solubility in
water is very low, and nutrient content is also limited by the low nutrient concentrations in peat and peat water.
Two strategies for oxygen absorption are observed in native peatland forests
(Fig. 1.17):
Tumih
Combretocarpus
rotundatus
Sago
(Metroxylon sagu)
Aerial Roots
Mound Roots
Jelutong
(Dyera costulata)
Fig. 1.17 Aerial roots and mound roots for oxygen and nutrient absorption in a native peatland
ecosystem. Mound roots exist in mounds and have several morphology types such as lateral roots,
aerial roots, mangrove-like roots, and so on
26
M. Osaki et al.