Nutrient dynamics in the Changjiang and retention effect in the Three Gorges Reservoir

Ding, Shiming; Chen, Peipei; Liu, Sumei; Zhang, Guoling; Zhang, Jing; Dan, Solomon Felix

doi:10.1016/j.jhydrol.2019.04.034

Cited by 57 publications

(36 citation statements)

References 83 publications

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“…Firstly, the dSi SGD inputs largely exceed the dSi riverine inputs by a factor of about 3-16 times for the BS, YS, and ECS (e.g. Ding et al, 2019;Liu et al, 2017a;Liu et al, 2017b;Wang et al, 2018b;Wu et al, 2017). Secondly, the bSi production seem to be mostly (62-90%) maintained by the recycling of Si (Li et al, 2019;Liu et al, 2005;Liu et al, 2016;Wu et al, 2017;Wu et al, 2020), which is unusual for coastal systems (Tréguer & De La Rocha, 2013).…”

Section: Chinese Seasmentioning

confidence: 99%

“…To date, preliminary Si budgets have been published for BS, YS and ECS (Li et al, 2019;Liu et al, 2005;Liu et al, 2016;Wu et al, 2017;Wu et al, 2020), but the estimates are still unbalanced since key fluxes, such as reverse weathering, are lacking. In addition, the relatively high load of lithogenic material in the Chinese marginal seas sediments, due to massive entrainment of siliceous soils through the hydrographic network of large rivers (Ding et al, 2019), make it difficult to quantify the bSi content in this system using a classic alkaline leach (DeMaster, 1981). We therefore recommend additional attention be paid to the cycling of Si within the Chinese marginal seas system in the near future.…”

Section: Chinese Seasmentioning

confidence: 99%

See 1 more Smart Citation

Reviews and syntheses: The biogeochemical cycle of silicon in the modern ocean

Tréguer¹,

Sutton²,

Brzezinski³

et al. 2020

Preprint

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Abstract. The element silicon (Si) is required for the growth of silicified organisms in marine environments, such as diatoms, which consume vast amounts of Si together with N, P, and C, connecting the biogeochemical cycles of these elements. Thus, understanding the Si cycle in the ocean is critical for understanding issues such as carbon sequestration by the ocean's biological pump. In this review, we show that recent advances in process studies indicate that total Si inputs and outputs, to and from the world ocean, are 57 % and 18 % higher, respectively, than previous estimates. We also update the total ocean silicic acid inventory value, which is about 24 % higher than previously estimated. These changes are significant, modifying factors such as the geochemical residence time of Si, which is now about 8000 years and two times faster than previously assumed. In addition, we present an updated value of the global annual pelagic biogenic silica production (255 Tmol-Si yr−1) based on new data from 49 field studies and 18 model outputs, and provide a first estimate of the global annual benthic biogenic silica production due to sponges (6 Tmol-Si yr−1). Given these important modifications, we address the steady state hypothesis of the Si cycle for past and modern oceans, and propose a possible steady state scenario for the global ocean (inputs = outputs = 14.8 Tmol-Si yr−1) and boundary exchange zone. Case studies for future programs are highlighted, and potential impacts of global change on the marine Si cycle discussed.

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Section: Chinese Seasmentioning

confidence: 99%

Section: Chinese Seasmentioning

confidence: 99%

Reviews and syntheses: The biogeochemical cycle of silicon in the modern ocean

Tréguer¹,

Sutton²,

Brzezinski³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…For example, frequent harmful algal blooms and seasonal hypoxia have been observed off the Changjiang Estuary (Li et al, 2002; Zhang, Liu, et al, 2007; Zhou et al, 2008; Zhu et al, 2011). Furthermore, the construction of the Three Gorges Dam, which has reduced nutrient and sediment loads from the Changjiang to the adjacent ECS, will have far‐reaching effects on environmental issues over the drainage basin and adjacent ECS (Chen, 2000; Ding et al, 2019; Gong et al, 2006; Jiang et al, 2014; Liu, Zhang, Chen, Wu, et al, 2003; Zhang et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Source Versus Recycling Influences on the Isotopic Composition of Nitrate and Nitrite in the East China Sea

et al. 2020

Self Cite

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Nitrogen transfer processes and NO3− sources in the East China Sea (ECS) were analyzed using dual isotopes of NO3− and NO2−, the concentration and isotopes of dissolved O2 and N2 gases, nutrient concentrations, and the hydrological conditions. It was clear that the δ15N and δ18O values of NO3− in the Changjiang freshwater were 5.6–6.6‰ and 0.6–1.0‰, respectively, affected by human activities (fertilizer, sewage, and manure) and nitrification. Off the Changjiang Estuary to the ECS continental slope, the NO3− concentration was lower or exhausted in the upper water layers, where both available δ15N and δ18O values for NO3− were high related to phytoplankton assimilation. In the lower water layers, organic matter remineralization, nitrification, and coupled sedimentary nitrification and denitrification resulted in low NO3− isotope values. Moreover, in the upper water layers of the ECS continental slope, NO3− showed high δ15N and δ18O values and low Δ(15, 18) values affected by assimilation, nitrification, and N2 fixation. NO2− in the ECS was dominated by NH4+ oxidation, and NO2− oxidation plays an important role in depleting NO2− in δ15N values. An overall NO3− budget is built for the ECS shelf, indicating that open boundary exchanges of NO3− flux and isotopes through Kuroshio invasion and Taiwan Warm Current Water are comparable to outflow off the ECS shelf, and nitrogen transformation processes (such as NO3− assimilation and nitrification) play an important role in nitrogen cycle, and NO3− is modified on the ECS shelf.

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“…The in uencing mechanisms of the changing hydrological regime on N cycling in the TGR have been revealed through laboratory experiments by arti cially increasing hydrostatic pressure, creating an anti-seasonal wet-dry cycle, and prolonging water residence time (Chai et al, 2016;Shi et al, 2020;Yu et al, 2020). However, most studies have preferred short-term investigation because of di culties in obtaining long-term observed data (Ding et al, 2019;Huang et al, 2014;Luo et al, 2011;Ran et al, 2017). The time variability of N in TGR involves a wide range of scales from days, months, to multi-years because of the coupled effect of natural (precipitation and monsoon) and anthropogenic (regular operation and staged impoundment of TGR) factors; as such, studies based on massive monitoring data are more valuable for assessing the longterm impact of TGR operation on N distribution.…”

Section: Introductionmentioning

confidence: 99%

Long-term impacts of reservoir operation on the spatiotemporal variation in nitrogen forms in the post-Three Gorges Dam period (2004–2016)

Nie

Chen

Niu

et al. 2021

Environ Sci Pollut Res

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Nitrogen (N) is an essential nutrient limiting life, and its biochemical cycling and distribution in rivers have been markedly affected by river engineering construction and operation. Here, we comprehensively analyzed the spatiotemporal variations and driving environmental factors of N distributions based on the long-term observations (from 2004 to 2016) of seven stations in the Three Gorges Reservoir (TGR). In the study period, the overall water quality status of the river reach improved, whereas N pollution was severe and tended to be aggravated after the TGR impoundment. The anti-seasonal reservoir operation strongly affected the variations in N forms. The total nitrogen (TN) concentration in the mainstream of the Yangtze River continuously increased, although it was still lower than that in the incoming tributaries (Wu and Jialing rivers). Further analysis showed that this increase occurred probably because of external inputs, including the upstream (76%), non-point (22%), and point source pollution inputs (2%). Besides, different N forms showed signi cant seasonal variations; among them, the TN and nitrate nitrogen concentrations were the lowest in the impoundment season (October-February), and the ammonia nitrogen concentrations were the highest in the sluicing season (March-May). These parameters varied likely because of internal N transformation. Redundancy analysis revealed that the water level regulated by the anti-seasonal operation was the largest contributor. Our ndings could provide a basis for managing and predicting the water quality in the Yangtze River.

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Nutrient dynamics in the Changjiang and retention effect in the Three Gorges Reservoir

Cited by 57 publications

References 83 publications

Reviews and syntheses: The biogeochemical cycle of silicon in the modern ocean

Reviews and syntheses: The biogeochemical cycle of silicon in the modern ocean

Source Versus Recycling Influences on the Isotopic Composition of Nitrate and Nitrite in the East China Sea

Long-term impacts of reservoir operation on the spatiotemporal variation in nitrogen forms in the post-Three Gorges Dam period (2004–2016)

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