Modelling agricultural nitrogen contributions to the Jiulong River estuary and coastal water

Cao, Wenzhi; Hong, Huasheng; Yue, Shiping

doi:10.1016/j.gloplacha.2004.10.006

Cited by 73 publications

(48 citation statements)

References 32 publications

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“…As a typical subtropical macro-tide estuary, its water temperature ranges from 13 to 32°C and maximum tidal current speeds during spring tide are >1.5 m s 1 in bottom waters and >2.0 m s 1 at surface and middle levels [32]. The flushing time in the JRE has been estimated at 2-3 d [33].…”

Section: Study Area and Sampling Sitesmentioning

confidence: 99%

“…In the JRE upper reach, NO 3 -N accounted for 55%-72% of DIN in dry seasons, and 67%-96% in wet seasons (Table 1, Figure 4). This indicates that most DIN in the JRE may result from chemical fertilizer application [33] and soil erosion in the watershed. This phenomenon is similar to the Yangtze [41], but it is different from the upper reach of the Pearl River Estuary of China.…”

Section: Characteristics and Decadal Changes Of Jre Nutrientsmentioning

confidence: 99%

“…In principle, based on the law of conservation of mass, mass balances of water/salt and biogenic elements are initially established in an estuary. Then, relevant fluxes of the targeted biogeochemical element are estimated [33,43].…”

Section: Export Fluxes Of Nutrients From Jre Into the Seamentioning

confidence: 99%

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Distribution, fluxes and decadal changes of nutrients in the Jiulong River Estuary, Southwest Taiwan Strait

et al. 2012

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The Jiulong River Estuary (JRE) is a typical subtropical macro-tide estuary on the southwest coast of the Taiwan Strait (TWS), which has been greatly impacted by human activities over the past 30 years. To understand nutrient dynamics and fluxes under such a heavy background of anthropogenic perturbation, eight cruises were conducted from April 2008 to April 2011, covering both wet (May to September) and dry (October to April next year) seasons. Nutrient concentrations were very high for the freshwater end-member in the upper reach of the JRE (nitrate (NO 3 In dry seasons, concentrations of these nutrients were higher than in wet seasons. Nitrate was the dominant chemical species of dissolved inorganic nitrogen (DIN), with percentages of 67%-96% in wet seasons and 55%-72% in dry seasons. Distributions of NO 3 -N and DSi against salinity were nearly constant during all cruises, and showed generally conservative mixing behaviors in the estuary (1

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Section: Study Area and Sampling Sitesmentioning

confidence: 99%

Section: Characteristics and Decadal Changes Of Jre Nutrientsmentioning

confidence: 99%

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Distribution, fluxes and decadal changes of nutrients in the Jiulong River Estuary, Southwest Taiwan Strait

et al. 2012

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“…The Jiulongjiang estuary is a typically subtropical system, with temperate climate and average annual rainfall of 1200 mm. The water temperature fluctuates from 13 to 32 • C and pH from 7.77 to 8.47 (Cao et al, 2005).…”

Section: Study Areasmentioning

confidence: 99%

“…is nutrients sink and/or source within the system. This is due to the application of inorganic N fertilizer (ammonium bicarbonate) in the drainage basins and wastewater discharge (Cao et al, 2005;Sheldrick et al, 2003;Yan et al, 1999;Millennium Ecosystem Assessment, 2005). Phosphate concentrations in 13 rivers are at the pristine level (0.5 µM) and in 5 rivers are at average level (3 µM) compared to the global river data .…”

Section: Nutrients In the Chinese Estuariesmentioning

confidence: 99%

Nutrient budgets for large Chinese estuaries

et al. 2009

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Abstract.Chinese rivers deliver about 5-10% of global freshwater input and 15-20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon) in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN) and depleted in dissolved inorganic phosphate (PO 3− 4 ) with very high DIN: PO 3− 4 concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3-4 times higher than those in the winter with the exception of NH + 4 . The flux of NH + 4 is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state massbalance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ∼4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea). This suggests that land-derived nutrients areCorrespondence to: S. M. Liu (sumeiliu@ouc.edu.cn) largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and atmospheric deposition.

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The nonconservative property of dissolved molybdenum in the western Taiwan Strait: Relevance of submarine groundwater discharges and biological utilization

Wang

Xia

et al. 2016

Geochem Geophys Geosyst

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This study examined dissolved Mo and sedimentary Mo along with hydrochemical parameters in the western Taiwan Strait (WTS) in May and August 2012. The results demonstrate that dissolved Mo could be depleted of as high as 10–20 nM during our May sampling period when the nutrient‐enriched Min‐Zhe coastal current ceased and spring blooms developed. The negative correlation between Chl‐a and dissolved Mo suggests the possible involvement of high algal productivity in removing dissolved Mo out of the water column. Specific oceanographic settings (little currents) permitted a high sedimentary enrichment of Mo (>6 µg/g Mo) within the highly productive waters outside the Jiulong River mouth. Possibly, the high algal productivities and consequent organic matter sinks provide a pathway of Mo burial from water columns into sediments. Dissolved Mo was relatively high in groundwater samples, but we observed that submarine groundwater discharges (SGDs) only contributed to a relatively small percentage of the total dissolved Mo pool in WTS. It is probably attributable to the immediate removal of SGD‐released Mo ions via adsorption onto newly formed Mn oxides once exposed to oxygenated seawater, followed by an elevated sedimentary Mo accumulation near the SGDs (∼5 µg/g). In addition to metal oxide particle scavenging and sulfide precipitation, we estimated that biological uptake along with Mo adsorption onto organic matter carriers could finally provide more than 10% of the annual sedimentary Mo accumulation in WTS.

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Modelling agricultural nitrogen contributions to the Jiulong River estuary and coastal water

Cited by 73 publications

References 32 publications

Distribution, fluxes and decadal changes of nutrients in the Jiulong River Estuary, Southwest Taiwan Strait

Distribution, fluxes and decadal changes of nutrients in the Jiulong River Estuary, Southwest Taiwan Strait

Nutrient budgets for large Chinese estuaries

The nonconservative property of dissolved molybdenum in the western Taiwan Strait: Relevance of submarine groundwater discharges and biological utilization

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