The Study Of Sulfide In The Sediment Of The Bohai, Yellow And East China Seas

The reduction of sulfate is one of organic matter degradation pathways in coastal sediment with high primary productivity, it can account for 50% of organic matter degradation. Sulfide which is the main component of sulfate reduction draws scientists'attention. Continental shelves have the buried information of sulfate reduction and sulfide formation that plays an important role in the the global sulfur cycle. The Bohai, Yellow and East China Seas are the marginal sea of the northeast Pacific which plays an important role in the global sulfur cycle, but nowadays little references on them were reported. The distribution of sulfide from in investigation region shows obvious spatial and temporal variations for the complexity of marine environment.1)The concentrations of AVS in Bohai, Yellow and East China Seas are in a low level compared to other areas. Concentration of AVS is the minimum in the East China Sea, lower in the South Yellow Sea, the highest in the Changjiang Estuary, the Bohai and the North Yellow Sea between them. In addition, concentration of AVS in the Changjiang Estuary is also higher due to terrestrial materials input from the Changjiang and the estuary has a higher sedimentation rate, and seasonal hypoxia events in the estuary attributes to the formation of AVS. However, AVS is not detected in the north East China Sea or has a low level(<2μmol/g dry)due to silt or sand sediment with sufficient supplement of oxygen through vertical exchange in seawater.2)In generally, the concentrations of AVS in The Yellow and Bohai Seas are higher in spring than in autumn, and in accordance with seasonal change of organic matter content; in the Changjiang estuary, sulfides and organic matter concentrations are lower in spring than in autumn affected by the CDW transport.3)The distribution characteristics of pyrite in the Bohai, Yellow and the East China Seas are also studied. The results show that the concentrations of pyrite at most investigation stations increased with depth, and the AVS: CRS ratio is generally less than 0.3, reflecting the high conversion of AVS to pyrite. The low sulfate and high sedimentation rates limit the conversion of AVS to pyrite in the Changjiang estuary, so the concentration of pyrite is low.