Submarine groundwater discharge estimation in an urbanized embayment in Hong Kong via short-lived radium isotopes and its implication of nutrient loadings and primary production.
(224)Ra and (223)Ra are adopted as tracers to qualify submarine groundwater discharge (SGD) in Tolo Harbor, a highly urbanized embayment in Hong Kong. Based on the sampling data, a two-layered radium mass balance model is used to estimate lateral SGD and bottom SGD. Total SGD is estimated to be 1.2-3.0 cm d(-1), including lateral SGD of 5.7-7.9 cm d(-1) and bottom SGD of 0.3-2.0 cm d(-1). Fresh SGD is estimated to be (2.1-5.5) × 10(5)m(3)d(-1). Nutrient fluxes (mold(-1)) from SGD are estimated to be (3-7.4) × 10(4) (dissolved inorganic nitrogen), (2.4-6.2) × 10(2) (dissolved inorganic phosphate) and (6.5-16) × 10(4) (dissolved silicate). Primary productivity is estimated to be (1.5-15) × 10(6)gCd(-1), 2-53% of which is supported by SGD-induced phosphate fluxes. The study indicates that SGD is a significant source of nutrients to coastal waters and may cause an obvious increase of primary production. These findings must be considered in future coastal ecological management.
Department of Earth Sciences, The University of Hong Kong, Hong Kong, China; The University of Hong Kong, Shenzhen Research Institude, Shenzhen, China.
Xin
X
Luo
Department of Earth Sciences, The University of Hong Kong, Hong Kong, China; The University of Hong Kong, Shenzhen Research Institude, Shenzhen, China. Electronic address: jjiao@hku.hk.
Jiu Jimmy
JJ
Jiao
Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC, United States.
W S
WS
Moore
Department of Earth Sciences, The University of Hong Kong, Hong Kong, China.
Chun Ming
CM
Lee
D004784:Environmental Monitoring / Q000379:methods*; D063366:Estuaries; D005068:Eutrophication; D060587:Groundwater / Q000032:analysis*; D006723:Hong Kong; D011883:Radium / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*
D011883:Radium
Mass balance model; Nutrient loadings; Primary production; Short-lived radium isotopes; Submarine groundwater discharge