CARBON STORAGE CAPACITY IN THE DAGUHE WETLAND,JIAOZHOU BAY OF QINGDAO

Estuarine wetland with high sedimentation rate is an important component of the coastal zone, where a great amount of organic matters are buried together with river sediments. The research of carbon storage capacity will help understand the role of the estuarine wetland in the global carbon cycle and climate changes. This paper takes the Daguhe estuarine wetland, which is located at Jiaozhou Bay, Qingdao, as an example. Three cores have been collected from the tidal flat and river bank marsh and sampled at a 2 cm interval. 117 samples are analyzed and tested in the laboratory for bold density (BD), grain size, total carbon (TC), total nitrogen (TN) and total organic carbon (TOC), carbon storage capacity are calculated with mass TC/TOC ratio and sedimentation rate which was calculated with ²¹⁰Pb, ¹³⁷Cs dating data from one of the three cores. The results show that TC burial flux at the river bank marsh is 102 gC/m²/a, and TOC burial flux is 84.8 gC/m²/a, whereas the TC and TOC burial flux of the tidal flat are 93.5 gC/m²/a and 69.9 gC/m²/a respectively. The area of the present natural wetland in Daguhe estuary is calculated from satellite images. It is estimated that in the 31 km² well preserved natural wetland,the average annual TC storage is 2.96 GgC, and TOC storage 2.27 GgC. Holocene sedimentary thickness in the Daguhe estuary delta varies from 3 m to 10 m. Take the average thickness of 6m into account, the total amount of carbon sequestration during the Holocene in the Daguhe wetlands was 66 GgC/km² of TC and 51 gC/m²/a of TOC. These figures are comparable to the carbon storage capacity of the offshore Bohai Sea and Yellow Sea, as well as other estuarine deltas around the world.