Responses of estuarine salinity and transport processes to sea level rise in the Zhujiang (Pearl River) Estuary

2016 ◽  
Vol 35 (5) ◽  
pp. 38-48 ◽  
Author(s):  
Yuxiang Chen ◽  
Juncheng Zuo ◽  
Huazhi Zou ◽  
Min Zhang ◽  
Kairong Zhang
2020 ◽  
Vol 201 ◽  
pp. 103245 ◽  
Author(s):  
Bo Hong ◽  
Zhonghui Liu ◽  
Jian Shen ◽  
Hui Wu ◽  
Wenping Gong ◽  
...  

2021 ◽  
Vol 9 (3) ◽  
pp. 291
Author(s):  
Jiaxi Wang ◽  
Bo Hong

The degradation of densely populated river delta environments due to the accelerating rise in sea level can affect the availability of freshwater for municipal supplies, irrigation, and industrial use. A fully calibrated three-dimensional numerical model is used in this study to evaluate the threat posed by the sea-level rise, which predicted to occur by 2100, to freshwater resources in the upper tributaries of Pearl River Estuary. The results indicate that both the intensity and duration of dry-season saltwater intrusion greatly increase as the sea level rises, making the water at drinking-water intake stations for the four waterworks no longer suitable for municipal supply. Flow modulation is performed to identify the threshold at which saltwater intrusion could be effectively suppressed in response to both sea-level rise and dry season hydrodynamics. The number of days for which water meets the drinking-water standard decreases as the sea level rises, but increases with increased river flow. The combined effect of future drought and sea-level rise would further limit the availability of freshwater in the upper tributaries. Stronger upstream salinity transport during flood tide are found in the sea-level rise case. The increased flood tidal salinity transport would have great impact on the tidal freshwater wetlands.


2020 ◽  
Author(s):  
Huixian Chen ◽  
Jianhua Wang ◽  
Nicole S. Khan ◽  
Jiaxue Wu ◽  
Benjamin P. Horton

<p>Proxy reconstructions of estuarine evolution provide perspectives on regional to global environmental changes, including relative sea-level changes, climatic changes, and agricultural developments. Although there are studies of the Holocene sedimentary processes in the Pearl River estuary, the understanding of early Holocene sedimentation in unknown due to limited preservation.</p><p>Here, we present a new record of lithological, benthic foraminiferal, and geochemical (δ<sup>13</sup>C and C/N) change from a sediment core in the west shoal of the modern Lingding Bay along a paleo-valley. The lithologic and foraminiferal record reveal the transgressive evolution from fluvial, inner estuary to middle estuary in the early Holocene between 11300 and 8100 cal a BP in response to rapid sea-level rise. δ<sup>13</sup>C and C/N data indicate high freshwater discharge from 10500 to 8100 cal a BP driven by a strong Asian monsoon. The middle Holocene (8100 - 3300 cal a BP) sediment is absent in this core and others in the northward of the Lingding Bay. Seismic profiles reveal a tidal ravinement surface across Lingding Bay, which contributed to subaqueous erosion on the mid-Holocene sedimentation hiatus, might be resulted from unique geomorphology of the Pearl River Delta. In the late Holocene (3300 cal a BP to the present), the lithology and foraminiferal assemblages suggest further regressive evolution from outer estuary, middle estuary channel, to middle estuary shoal due to deltaic progradation under stable relative sea levels. In the last 2000 years, δ<sup>13</sup>C and C/N values reveal the intensive development of agriculture coupled with the reduction of freshwater input derived from a weakening Asian monsoon. Our study illustrates the interaction of Asian monsoon and sea-level changes within the Pearl River estuary landform and their impact on Holocene sedimentary processes.</p>


2021 ◽  
Vol 8 ◽  
Author(s):  
Weiyuan Kong ◽  
Liping Zhou ◽  
Georges Aumaître ◽  
Didier Bourlès ◽  
Karim Keddadouche

The ratio of cosmogenic 10Be and its stable isotope 9Be has been used as a proxy of long-term continental weathering fluxes and denudation rates, but transport processes of these isotopes from river water to estuarine water and seawater, as well as interference of potential anthropogenic source of 9Be on natural 10Be/9Be around populated estuaries are not well constrained. Here, we present results of 10Be and 9Be concentrations of dissolved and reactive particulate phase in the Pearl River Estuary (PRE) and its eight major outlets. The concentrations of Cu, Cd, and Pb are also measured, allowing us to assess their contamination levels and anthropogenic source together with 9Be by the geo-accumulation index (Igeo–reac) and enrichment factor (EF). A wide distribution pattern of dissolved 10Be (137–1,194 at/gwater) and 9Be (0.781–8.31 × 10–12 g/gwater) among these outlets is observed. The distribution coefficients (Kd) of both isotopes between sediment and water are in the order of 105, and on average only 5% of 10Be exists as dissolved form. Compared with total meteoric 10Be deposited on the river basin, 23% of the meteoric 10Be is retained while 38% of 10Be finally escape the estuary and is transported into coastal seawater. Despite the high contamination levels of Cu and Cd, the lower Igeo–reac and EF values of 9Be indicate that 9Be is hardly polluted by anthropogenic source. Thus, the 10Be/9Be in the PRE area is mainly associated with natural processes instead of human activities.


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