|
|
|
|
|
|
|
![](images/dian9.gif) |
Biogeochemical processes in land-ocean interfaces, surface estuaries, subterranean estuaries and sediment-water interface
|
|
|
Submarine groundwater discharge and its associated chemical fluxes in the Pearl River Estuary Monday 7th @ 1110-1130, Conference Room 1 Guizhi Wang* , Xiamen University Shilei Jin, Xiamen University Qing Li, Xiamen University Shengyao Sun, Xiamen University Moge Du, Xiamen University Weizhen Jiang, Xiamen University Minhan Dai, Xiamen University Jianping Gan, Hong Kong University of Science and Technology Presenter Email: gzhwang@xmu.edu.cn |
Distributions of radium isotopes were investigated in the Pearl River Estuary (PRE) to quantify submarine groundwater discharge (SGD). The water in PRE is mainly a mixture of river water, ocean water and groundwater. Based on conservation of salinity and 226Ra, we set up a three-endmember mixing model to solve for the fraction of the river water, ocean water, and the groundwater. River water contributed 78±13% of the water mass in PRE, while the ocean water accounted for 19±13% and the groundwater accounted for 3±2%. Using a tidal prism model the flushing time was estimated to be 7.1±0.9 days. Based on the mass balance of 226Ra and 228Ra and the assumption of steady state, the flux of SGD was estimated to be 0.83±0.63-1.07±0.83×108 m3 d-1, which is equivalent to 16-20% of the concurrent Pearl River discharge. The net solute flux via SGD was calculated to be 3.13±2.78×108 mol d-1 for DIC, 1.56±1.96×107 mol d-1 for DOC, 7.35±14.9×104 mol d-1 for soluble reactive phosphorus (SRP), 2.81±2.44×107 mol d-1 for silicate, and 2.67±2.42×107 mol d-1 for dissolved inorganic nitrogen (DIN). The net SGD-associated solute flux accounts for 43% of the estuarine export flux for DIC, 6.69% for SRP, 37% for silicate, and 32% for DIN and is equivalent to 58% of the riverine flux for DIC, 6.99% for SRP, 33% for silicate, and 27% for DIN. |
|
|
|
|
|
|
|
|