Sulfur cycle in the typical meadow Calamagrostis angustifolia wetland ecosystem in the Sanjiang Plain,Northeast China

The sulfur cycle and its compartmental distribution within an atmosphere-plant-soil system was studied using a compartment model in the typical meadow Calamagrostis angustifolia wetland in the Sanjiang Plain Northeast China.The results showed that in the typical meadow C.angustifolia wetland ecosystem,soil was the main storage compartment and current hinge of sulfur in which 98.4%sulfur was accumulated,while only 1.6%sulfur was accumulated in the plant compartment.In the plant subsystem,roots and litters were the main storage compartment of sulfur and they remained 83.5%of the total plant sulfur.The calculations of sulfur turnover through the compartments of the typical meadow C.angustifolia wetland ecosystem demonstrated that the above-ground component took up 0.99 gS/m;from the root,of which 0.16 gS/m;was translocated to the roots and 0.83 gS/m;to the litter.The roots took in 1.05 gS/m;from the soil,subsequent translocation back to the soil accounted for 1.31 gS/m;,while there was 1.84 gS/m;in the litter and the net transfer of sulfur to the soil was more than 0.44 gS/（m;·a）.The emission of H;S from the typical meadow C.angustifolia wetland ecosystem to the atmosphere was 1.83 mgS/（m;·a）,while carbonyl sulfide（COS）was absorbed by the typical meadow C.angustifolia wetland ecosystem from the atmosphere at the rate of 1.76 mgS/（m;·a）,The input of sulfur by the rainfall to the ecosystem was 4.85 mgS/m;during the growing season.The difference between input and output was 4.78 mgS/m;,which indicated that sulfur was accumulated in the ecosystem and may cause wetland acidify in the future.