TROPICAL GEOGRAPHY ›› 2015, Vol. 35 ›› Issue (3): 298-305.

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Spatial and Seasonal Variation of Nutrients Transportation in the Maozhou Estuary of Shenzhen, Guangdong

ZHU Aiping,CHEN Jianyao,JIANG Tao,LI Kun,GAO Qingwang,CHEN Yidong,ZHONG Jinlong   

  1. (School of Geography and Planning,Sun Yat-Sen University,Guangzhou 510275,China)
  • Online:2015-06-05 Published:2015-06-05

Abstract:

In order to investigate the spatial and seasonal variation of nutrients and associated flux within a tidal cycle in the Maozhou Estuary, thirty-six water samples were collected from 3 sites (A1, A2 and A3) every two hours in January 2014 and analyzed for NH4+-N, -N, DTN,PO43--P, DTP, and  

In order to investigate the spatial and seasonal variation of nutrients and associated flux within a tidal cycle in the Maozhou Estuary, thirty-six water samples were collected from 3 sites (A1, A2 and A3) every two hours in January 2014 and analyzed for NH4+-N, -N, DTN, PO43--P, DTP, and SiO32--Si. The results showed that the concentrations of NH4+-N, DTN, PO43--P, SiO32--Si were 15.8~19.8, 18.0~29.0, 0.25~2.15 and 6.16~9.03 mg/L at A1, 11.5~23.4, 25.9~53.6, 1.70~2.70 and 5.04~6.28 mg/L at A2, and 0.74~7.39, 3.06~24.9, 0.01~0.98 and 2.77~4.17 mg/L at A3, respectively. The changes of -N, DTN were consistent with that of tide at A2 except  PO43--P, DTP and SiO32--Si. NH4+-N and  PO43--P were found to be the major components of nitrogen and phosphorus. All nutrients except nitrate were correlated at a significant level of 0.01 with each other, indicating a common source of nutrients. Sewage discharge to the Maozhou River contributed principally to the high concentration of NH4+-N in the estuary. According to the results of nutrient ratios, it was considered that phosphate was a limiting factor for phytoplankton growth in the Maozhou Estuary. The fluxes of nutrients were calculated, yielding a high flux of -N of 48.0 and 71.8 g/s at A1 and A2 respectively.

Si. The results showed that the concentrations of NH4+-N, DTN, PO43--P, SiO32--Si were 15.8~19.8, 18.0~29.0, 0.25~2.15 and 6.16~9.03 mg/L at A1, 11.5~23.4, 25.9~53.6, 1.70~2.70 and 5.04~6.28 mg/L at A2, and 0.74~7.39, 3.06~24.9, 0.01~0.98 and 2.77~4.17 mg/L at A3, respectively. The changes of -N, DTN were consistent with that of tide at A2 except PO43--P, DTP and SiO32--Si.  NH4+-N and PO43--P were found to be the major components of nitrogen and phosphorus. All nutrients except nitrate were correlated at a significant level of 0.01 with each other, indicating a common source of nutrients. Sewage discharge to the Maozhou River contributed principally to the high concentration of NH4+-N in the estuary. According to the results of nutrient ratios, it was considered that phosphate was a limiting factor for phytoplankton growth in the Maozhou Estuary. The fluxes of nutrients were calculated, yielding a high flux of -N of 48.0 and 71.8 g/s at A1 and A2 respectively.

Key words: nutrients, tidal change, nutrient flux, the Maozhou Estuary