Saltwater Intrusion Induced by a Complete Neap Tide and Its Effect on Nutrients Variation in the Estuary of Pearl River, China

Long, Aimin; Ling-yan, Sun; Shi, Ronggui; Zhou, Weihua; Dang, Anh Tien

doi:10.2112/jcoastres-d-12-00182.1

Cited by 17 publications

(6 citation statements)

References 14 publications

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“…Stratification is a common phenomenon in estuarine regions with a less dense freshwater surface and deeper saltwater layers that can result in significant intrusions due to physical forcing and tidal influences [2]. It has been identified as an important mechanism in the spatial and temporal regulation of phytoplankton community and primary production in estuarine systems [33].…”

Section: Disscusionmentioning

confidence: 99%

“…Tidal dynamics play a critical role in affecting estuarine biological production, water quality, material transport and dispersion [1, 2]. Saltwater intrusion, a universial phenomenon in estuaries, is the movement of saline water into freshwater aquifers that partly results from tidal action, and has a profound effect on the estuarine ecosystem and environment [2].…”

Section: Introductionmentioning

confidence: 99%

“…Saltwater intrusion, a universial phenomenon in estuaries, is the movement of saline water into freshwater aquifers that partly results from tidal action, and has a profound effect on the estuarine ecosystem and environment [2]. Saltwater intrusion plays an important role in the distribution of chemical and biological variables in estuarine waters [3, 4].…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of Phytoplankton Biomass, Primary Production and Community Structure in the Modaomen Channel, Pearl River Estuary, with Special Reference to the Influence of Saltwater Intrusion during Neap and Spring Tides

et al. 2016

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In recent decades, increasing frequency and intensity of saltwater intrusion in the Modaomen Channel has threatened the freshwater supply in the surrounding cities of the Pearl River Estuary, and ulteriorly changed the environmental conditions of the estuarine waters. Phytoplankton biomass, primary production (PP) and species composition, as well as hydrological and chemical parameters were examined along a downstream transect in the Modaomen Channel during neap tide (NT) and spring tide (ST), when a strong saltwater intrusion event occurred in late September, 2011. A total of 46 species phytoplankton were identified, including Bacillariophyta (25 species), Dinoflagellate (14 species), Chlorophyta (4 species), Cyanophyta (2 species) and Euglenozoa (1 species). The dominant species were shifted from freshwater diatoms (e.g., Melosira granulata and Melosira granulata var. angustissima) in the upper reaches to saline water diatoms (e.g., Skeletonema costatum and Coscinodiscus sp.) in the river mouth. Generally, phytoplankton density, biomass (chl-a) and PP decreased from the upper to lower reaches along the channel, and were significantly higher in NT than those of ST. There was a shift from large-sized phytoplankton (>20 μm) in the upper reaches to relative small-sized cells (5–20 μm) in the lower reaches. Compared to NT, low discharge and flow velocity, coupled with strong easterly winds during ST specially aggravated saltwater intrusion further to the upstream (~50 km from the estuary). The intruded saltwater diluted nutrients, N/P ratios, chl-a, and phytoplankton abundances, and thereby led to a decline in PP during ST.

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Section: Disscusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characteristics of Phytoplankton Biomass, Primary Production and Community Structure in the Modaomen Channel, Pearl River Estuary, with Special Reference to the Influence of Saltwater Intrusion during Neap and Spring Tides

et al. 2016

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“…According to the National Hygienic Standard for Drinking Water (GB 5749-2006) in China, the 250-mg/L isohaline is defined as the recommended salinity threshold value of river water for drinking purposes. Severe saltwater intrusion in the Pearl River Estuary has tremendously affected surface water and groundwater quality, and changed the biodiversity of terrestrial and aquatic communities (Long et al, 2013;Wang and Hong, 2021). From 2009 to 2020, a total of 68 saltwater intrusion events occurred in the Pearl River Estuary, with an average of 5.67 per year (Figure 10A).…”

Section: Environmental Response To Alterations In Sediment Regimementioning

confidence: 99%

Long-term variations in water discharge and sediment load of the Pearl River Estuary: Implications for sustainable development of the Greater Bay Area

Liu

Fagherazzi²,

Liu³

et al. 2022

Front. Mar. Sci.

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The water discharge and sediment load have been increasingly altered by climate change and human activities in recent decades. For the Pearl River, however, long-term variations in the sediment regime, especially in the last decade, remain poorly known. Here we updated knowledge of the temporal trends in the sediment regime of the Pearl River at annual, seasonal and monthly time scales from the 1950s to 2020. Results show that the annual sediment load and suspended sediment concentration (SSC) exhibited drastically decreased, regardless of water discharge. Compared with previous studies, we also found that sediment load and SSC reached a conspicuous peak in the 1980s, and showed a significant decline starting in the 2000s and 1990s, respectively. In the last decade, however, water discharge and sediment load showed slightly increasing trends. At the seasonal scale, the wet-season water discharge displays a decreasing trend, while the dry-season water discharge is increasing. At the monthly scale, the flood seasons in the North and East Rivers typically occur one month earlier than that in the West River due to the different precipitation regimes. Precipitation was responsible for the long-term change of discharge, while human activities (e.g. dam construction and land use change) exerted different effects on the variations in sediment load among different periods. Changes in the sediment regime have exerted substantial influences on downstream channel morphology and saltwater intrusion in the Greater Bay Area. Our study proposes a watershed-based solution, and provides scientific guidelines for the sustainable development of the Greater Bay Area.

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“…Strati cation is a physical condition of the water column that reduces vertical water mixing between the surface and bottom layers of the aquatic environment and has a signi cant effect on the distribution, dispersal, recirculation, exchange, and partitioning processes of microbial communities, algae, nutrients, and metals in the system (Long et al 2013; Liu and de Swart 2017; Shilei et al 2020; Jia et al 2021). In an estuarine environment, strati cation occurs mainly by horizontal and vertical density gradients owing to the difference in density between seawater and freshwater in the water column.…”

Section: Introductionmentioning

confidence: 99%

Effect of benthic fluxes on nutrient dynamics of bottom water during stratification in a brackish lake

Kwak

Jeong

Choi

2023

Preprint

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We performed in-situ investigations using a benthic lander to examine changes in the sediment oxygen demand (SOD) and benthic nutrient fluxes during development of stratification in the downstream area of an artificially constructed brackish lake, Saemangeum Lake. During each measurement period, the water temperature and salinity in the water column showed a vertically stable stratified structure. The potential energy anomaly (PEA) was 88.1–125.7 J/m3, and the intensity of the stratification gradually strengthened during the entire measurement period. The DO concentration in the bottom water gradually decreased corresponding to the intensified stratification of water with the increase in temperature; thereby, establishing hypoxic conditions. As the stratification intensified, the SOD decreased with the decrease in DO concentration in the bottom water, and the benthic fluxes of NH4-N and PO4-P exhibited the opposite effect. When the effect of offshore water (through the sluice gate of the dike) was insignificant, the SOD contributed 33% of the net DO loss below the pycnocline. During this period, the benthic NH4-N and PO4-P fluxes were estimated to contribute 55% and 87% to the net fluxes of NH4-N and PO4-P, respectively, in the water column below the pycnocline. Additionally, the benthic NH4-N and PO4-P fluxes resulted in excess phosphorus in the bottom water. When the inflow of seawater through the sluice gate is sufficient, the flow in the upstream direction of the bottom layer will move the phosphorus-rich bottom water in the downstream, which is important for algae growth in the middle-upstream.

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Saltwater Intrusion Induced by a Complete Neap Tide and Its Effect on Nutrients Variation in the Estuary of Pearl River, China

Cited by 17 publications

References 14 publications

Characteristics of Phytoplankton Biomass, Primary Production and Community Structure in the Modaomen Channel, Pearl River Estuary, with Special Reference to the Influence of Saltwater Intrusion during Neap and Spring Tides

Characteristics of Phytoplankton Biomass, Primary Production and Community Structure in the Modaomen Channel, Pearl River Estuary, with Special Reference to the Influence of Saltwater Intrusion during Neap and Spring Tides

Long-term variations in water discharge and sediment load of the Pearl River Estuary: Implications for sustainable development of the Greater Bay Area

Effect of benthic fluxes on nutrient dynamics of bottom water during stratification in a brackish lake

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