Assessing soil and sediment organic carbon sequestration potential of selected wetlands at different physiographic regions of West Bengal, India

Abstract

Wetlands provide numerous ecosystem services including sequestration of atmospheric carbon–dioxide (CO ) which play an important role in mitigation of green- 2 house gases (GHGs). Present study aimed to assess soil / sediment carbon (C) stock of different wetlands under different physiographic regions of West Bengal. West Bengal has a number of wetlands situated in different biogeographic regions like lower Gangetic plains, central Himalaya, Chotanagpur plateau and coasts. A total of 19 wetlands were selected for present study and were categorized into six wetland types viz., floodplain wetlands (FP), wetlands from forested hill region (FH), Himalayan region (HM), Chotanagpur plateau and adjacent area (CP), coastal wetlands (CO) and wastewater–fed fishponds of East Calcutta Wetlands (ECW) ecosystems. Soil / sediment organic carbon (SOC) content of both bank soil and bottom sediments of the wetlands varied widely among study sites. Highest amount of bank SOC were recorded from HM wetlands (50.54 ± 6.65 t ha–1) whereas bottom SOC values from FP wetlands (36.81±17.80 t ha–1). Different allochthonous inputs like sewage water, runoff from catchment area; wetland macrophytes; sediment texture; physicochemical properties of water influence C sequestration potential of wetlands. Findings of present study can be compared with 22.35% of total wetland area of the state and it can be assumed that these types of wetlands can sequester 6.63 M t carbon in soils and sediments.