Evolution of the sink and source of dissolved inorganic nitrogen with salinity as a tracer during summer in the Pearl River Estuary

Wu, Mei-Lin; Hong, Yiguo; Yin, Jingdong; Dong, Junde; Wang, You‐Shao

doi:10.1038/srep36638

Cited by 22 publications

(19 citation statements)

References 49 publications

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“…Observed DIN had higher concentrations in the western estuary. These nitrogen deviations in the east and west PRE suggested different degrees of active internal N cycling, as discussed in other studies (Chai et al, 2006(Chai et al, , 2009Wu et al, 2016). The DIP removal was mainly induced by the biological response and adsorption on the suspended particles, while the P sink was likely due to the P replenishment (as in the middle estuary) and fertilizers in the agricultural applications (Li et al, 2017;Wang, 2018).…”

Section: Effect Of the Pearl River Dischargementioning

confidence: 53%

“…The data preparations for Pearson correlation, linear regression, and PCA are conducted using the statistical package IBM SPSS Statistics 20 for Windows. The two end-member mixing model is introduced to differentiate biological processes from the effects of physical mixing, as used in the earlier studies of Han et al (2012), Wu et al (2016), Li et al (2017), and Niu et al (2020). These two end members have different nutrient conditions.…”

Section: Discussionmentioning

confidence: 99%

“…The human activities induced in the 1990s of the PRE were land reclamation and channel dredging, resulting in a declined water area. The estuary then became narrower and deeper, preventing the diffusion and transport of the pollutants (Li et al, 2014;Wu et al, 2016;Niu et al, 2020). Therefore, the nutrient pollution caused by nitrogen and silicate was detected in the upper estuary because of the riverine influence.…”

Section: Correlation Between Chlorophyll-a and Environmental Factorsmentioning

confidence: 99%

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Nutrient Pollution and Its Dynamic Source-Sink Pattern in the Pearl River Estuary (South China)

Tao¹,

Niu²,

Dong³

et al. 2021

Front. Mar. Sci.

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Nutrient enrichment and its quantitative cause-effect chains of the biogeochemical processes have scarcely been documented in the Pearl River Estuary (South China). Field investigations of nutrient samples taken between 1996 and 2018 showed significant differences in nitrogen and phosphorus with times and sites. The concentrations of DIN and DIP gradually increased over the past two decades, with good fitted linear curves (R2 = 0.31 for DIN, R2 = 0.92 for DIP); while the temporal variation in DSi was non-significant. Higher levels of nitrogen and silicate mainly appeared in the upper estuary because of the riverine influence. The phosphorus pollution was accumulated in the northeast (e.g., Shenzhen bay). The aquatic environment was highly sensitive to nutrient pollution and eutrophication risk, which accordingly corresponded to high phytoplankton production and biodiversity. Phosphorus was the limiting factor of phytoplankton growth in this estuary, and more frequently caused the eutrophication risks and blooms. The nutrient pollution was largely influenced by riverine inputs, quantified by PCA-generation, and the contributions of coastal emission and atmospheric deposition were followed. The two-end member mixing model differentiated the physical alterations from the biological activity and identified the dynamic source-sink patterns of nutrient species. Nitrogen and silicate had relatively conservative behaviors in the estuary and phosphate showed an active pattern.

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Section: Effect Of the Pearl River Dischargementioning

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Section: Correlation Between Chlorophyll-a and Environmental Factorsmentioning

confidence: 99%

See 1 more Smart Citation

Nutrient Pollution and Its Dynamic Source-Sink Pattern in the Pearl River Estuary (South China)

Tao¹,

Niu²,

Dong³

et al. 2021

Front. Mar. Sci.

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“…Nitrite and nitrate levels (μM) were measured by using a modified zinc–cadmium reduction method (MZCRM), as described by Wu J. et al (2016) . The dissolved NH 4+ (μM) of the water samples was analyzed with methods of oxidized by hypobromite ( Wu M. et al, 2016 ).…”

Section: Methodsmentioning

confidence: 99%

Spatial Variability and Co-acclimation of Phytoplankton and Bacterioplankton Communities in the Pearl River Estuary, China

et al. 2018

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Phytoplankton and bacterioplankton play significant roles in estuarine systems. It is important to demonstrate the spatial variability of bacterial and microalgal communities and understand the co-acclimation of these organisms to different environmental factors. In this study, MiSeq sequencing and morphological identification were applied to analyze the variations in bacterial and microalgal communities in the Pearl River Estuary, respectively. Molecular ecological network analysis was used to investigate the potential interactions between microalgae and bacteria and illustrate the responses of these interactions to environmental gradients. The results revealed that microalgal/bacterial communities in freshwater samples were distinct from those in mesohaline water samples. Microalgae affiliated to the genus Skeletonema dominated the mesohaline water phytoplankton communities, while Melosira was the more abundant genus in freshwater communities. Actinobacteria, Alphaproteobacteria, Betaproteobacteria, and Acidimicrobiia dominated bacterial communities in freshwater samples, while Gammaproteobacteria, Bacilli, and Synechococcophycideae were more abundant in mesohaline water samples. Tightly correlations were observed between phytoplankton and bacterioplankton. These interactions were regarded to be key factors in shaping the community structures. Further, the KEGG database and PICRUSt were used to predict the functions of bacterioplankton in the process of nitrogen cycling. The results indicated that denitrification could play an important role in nitrogen loss and might alleviate the eutrophication in the Pearl River Estuary. Collectively, the results in this study revealed that substantial changes in phytoplankton and bacterioplankton communities were correlated with the gradients of environmental parameters in the Pearl River Estuary. The results also demonstrated that the interactions between phytoplankton and bacterioplankton were important for these organisms to acclimate to changing environments.

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“…Continental shelves are regions of high productivity and account for about 14% of the total production of the global ocean [2]. This is due to the rapid conversion of nutrients and the high nutrient supply from rivers, wind-driven coastal upwelling, and tidal mixing [3][4][5][6][7][8]. The biophysical responses of continental shelves are affected by their width, depth, coastline, and the shape of their connection with the adjacent ocean [9][10][11], in addition to the latitude, intensity of sun exposure and seasonal temperature differences [12][13][14], and the influence of differences in the wind fields [4,15,16].…”

Section: Introductionmentioning

confidence: 99%

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

et al. 2021

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Low-level jet (LLJ) significantly affects the synoptic-scale hydrometeorological conditions in the South China Sea, although the impact of LLJs on the marine ecological environment is still unclear. We used multi-satellite observation data and meteorological reanalysis datasets to study the potential impact of LLJs on the marine biophysical environment over the Beibuwan Gulf (BBG) in summer during 2015–2019. In terms of the summer average, the sea surface wind vectors on LLJ days became stronger in the southwesterly direction relative to those on non-LLJ days, resulting in enhanced Ekman pumping (the maximum upwelling exceeds 10 × 10−6 m s−1) in most areas of the BBG, accompanied by stronger photosynthetically active radiation (increased by about 20 μmol m−2 s−1) and less precipitation (decreased by about 3 mm day−1). These LLJ-induced hydrometeorological changes led to an increase of about 0.3 °C in the nearshore sea surface temperature and an increase of 0.1–0.5 mg m−3 (decrease of 0.1–0.3 mg m−3) in the chlorophyll-a (chl-a) concentrations in nearshore (offshore) regions. Intraseasonal and diurnal changes in the incidence and intensity of LLJs potentially resulted in changes in the biophysical ocean environment in nearshore regions on intraseasonal and semi-diurnal timescales. The semi-diurnal peak and amplitude of chl-a concentrations on LLJ days increased with respect to those on non-LLJ days. Relative to the southern BBG, LLJ events exhibit greater impacts on the northern BBG, causing increases of the semi-diurnal peak and amplitude with 1.5 mg m−3 and 0.7 mg m−3, respectively. This work provides scientific evidence for understanding the potential mechanism of synoptic-scale changes in the marine ecological environment in marginal seas with frequent LLJ days.

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Evolution of the sink and source of dissolved inorganic nitrogen with salinity as a tracer during summer in the Pearl River Estuary

Cited by 22 publications

References 49 publications

Nutrient Pollution and Its Dynamic Source-Sink Pattern in the Pearl River Estuary (South China)

Nutrient Pollution and Its Dynamic Source-Sink Pattern in the Pearl River Estuary (South China)

Spatial Variability and Co-acclimation of Phytoplankton and Bacterioplankton Communities in the Pearl River Estuary, China

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

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