Estuarine morphology and depositional processes in front of lateral river-dominated outlets in a tide-dominated estuary: A case study of the Lingding Bay, South China Sea

Deng, Junjie; Yao, Qiangsheng; Wu, Jiaxue

doi:10.1016/j.jseaes.2020.104382

Cited by 10 publications

(18 citation statements)

References 29 publications

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“…As the sea level in the PRE rises, the tidal range will increase, especially in the upper estuary (Hong et al, 2020). The increased tidal range and consequent amplified tidal current will enhance the erosion of the West Shoal, due to increases in resuspension and the seaward sediment flux (Deng et al, 2020).…”

Section: Comparison With Previous Studies and Implications For Future Morphological Evolution Of The Prementioning

confidence: 99%

“…With the decrease in riverine sediment discharge (Zhang et al, 2019), the increasing frequency of storms and typhoons (Chen et al, 2019), the rising sea level and consequent increases in tidal range and current (Deng et al, 2020;Hong et al, 2020), the PRE has a higher risk of erosion in the future.…”

Section: Comparison With Previous Studies and Implications For Future Morphological Evolution Of The Prementioning

confidence: 99%

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Wave Effects on Sediment Transport and Entrapment in a Channel‐Shoal Estuary: The Pearl River Estuary in the Dry Winter Season

et al. 2021

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Sediment dynamics have substantial effects on the morphology of estuaries and deltas (Wright & Coleman, 1973) and have an enormous influence on estuarine and marine environments (Turner & Millward, 2002). Sediment transport and distribution in estuaries are heavily affected by river's discharge of freshwater and sediment, and by tides, winds, waves, and bathymetry (Dyer, 1997).The supply of river sediments to many estuarine systems has decreased over the past 50 years, especially in Africa and Asia, due to upstream damming and sand extraction (Syvitski et al., 2005(Syvitski et al., , 2009. This reduction in sediment input alters the morphology of estuaries, deltas, and coasts, and leads to depletion of the Abstract Sediment dynamics have great effects on the morphology of estuaries and deltas. As riverine sediment input has decreased in many estuaries in recent years, the removal and dispersion of sediments by currents and waves inside estuaries has assumed a more dominant role; however, the overall effects of waves are less well understood. In this study, we used the Coupled Ocean Atmosphere Wave Sediment Transport system to model the effects of waves on sediment transport in China's Pearl River Estuary. The results indicate that the presence of waves increased the landward current and sediment transport at the bottom of the channel and the seaward fluxes of water and sediment at the West Shoal, which is the main shallow area that accepts riverine sediment. Relative to the case without waves, the effects of waves increased the estuary's total sediment export by 45% to 9.14 megatons in one typical year, which even exceeded the annual riverine load in the year. The dry winter season shows the highest wave effects on sediment budget, and the sediment export was increased by 86% to 2.59 megatons with waves when compared with that without waves. This increase export was mainly concentrated at the surface near the western shore. Moreover, the waves increased lateral sediment entrapment in the Southwest Shoal, which explains the local geomorphologic evolution in recent decades. This study is of implication for the study on sediment exchange between shoal and channel in estuaries and on the fates of riverine sediment from source to sink.Plain Language Summary Waves have significant impacts on estuarine mixing, circulation, and sediment dynamics, which may affect the morphology of estuaries and deltas, water quality, and the overall estuarine ecosystems. Despite these substantial effects, the mechanisms of wave effects affecting estuarine circulation and lateral sediment entrapment in a channel-shoal estuary have not received adequate attention. Here, we use a validated coupled ocean model system to investigate the wave effects on longitudinal/lateral circulation and sediment transport/entrapment in a channel-shoal estuary. We note that the waves influence the surface and bottom stress, vertical mixing, and sediment resuspension. And in turn, these lead to the enhancement of tidal asymmetries and seaward sediment flux. M...

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Section: Comparison With Previous Studies and Implications For Future Morphological Evolution Of The Prementioning

confidence: 99%

Section: Comparison With Previous Studies and Implications For Future Morphological Evolution Of The Prementioning

confidence: 99%

Wave Effects on Sediment Transport and Entrapment in a Channel‐Shoal Estuary: The Pearl River Estuary in the Dry Winter Season

et al. 2021

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“…For instance, when we queried for species that have experienced at least 2° (220 km—1° = 110 km) change in mean latitudinal centroids, ~15% of the species in this study showed northward shifts and ~11% southward shifts. These bidirectional shifts could have occurred in several ways, which include (i) the relatively low, especially negative sea‐surface temperature anomalies over the southern region implies that estuaries in this region have experienced periods of cooling and perhaps facilitated southward range expansion of some species and (ii) some estuaries could be exhibiting inertia, arising from their geomorphologies, tidal actions and freshwater input among other factors (Ban et al, 2016; Deng et al, 2020; Gillanders et al, 2011), neutralizing potential climate‐mediated impacts on productivity and recruitment. These estuaries could then function as climate refugia (Ban et al, 2016), especially for transient species, leading to a multi‐directional movement pattern.…”

Section: Discussionmentioning

confidence: 99%

Sea‐surface temperature anomalies mediate changes in fish richness and abundance in Atlantic and Gulf of Mexico estuaries

Oke

Zhang

Keyser

et al. 2022

Journal of Biogeography

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Aim Anthropogenic warming of marine systems has caused biological and physiological responses that are fundamentally altering ecosystem structure. Because estuaries exist at the land‐ocean interface, they are particularly vulnerable to the effects of ocean warming as they can undergo rapid biogeochemical and hydrological shifts due to climate and land‐use change. We explored how multiple components of estuarine fish diversity—turnover, richness, and abundance—have changed in the North Atlantic and Gulf of Mexico estuaries across space and time and the drivers of change. Location North Atlantic and Gulf of Mexico. Taxa Fish. Method We compiled long‐term (>30 years), continent‐wide fisheries independent trawl surveys conducted in estuaries—from the Gulf of Maine to the Gulf of Mexico (U.S. waters)—and combined these with climate and land‐use‐land‐cover data to examine trends and ecological drivers of fish richness, abundance and turnover using mixed‐effect models. Results Species richness, abundance and turnover have increased in North Atlantic and Gulf of Mexico estuaries in the last 30 years. These changes were mediated largely by sea‐surface temperature anomalies, especially in more northern estuaries where warming has been relatively pronounced. Main Conclusion The increasing trajectory of turnover in many estuaries suggests that fish communities have changed fundamentally from the baselines. A fundamental change in community composition can lead to an irreversible trophic imbalance or alternative stable states among other outcomes. Thus, predicting how shifting community structures might influence food webs, ecosystem stability, and human resource use remain a pertinent task.

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“…The amplitude of M2 is 0.63 m at the mouth of the Humen Channel, which decreased seaward in Lingding Bay (Mao et al, 2004). The tidal prism in Lingding Bay decreased from the 1900s to the 2010s (Deng & Bao, 2011). Tidal ranges at river mouths have increased since the 2010s, resulting from increasing water volume of the bay Yang et al, 2019).…”

Section: Research Areamentioning

confidence: 99%

Asymmetric evolution of river mouth bifurcation under angled river‐tide interaction, a case study at river mouths of Lingding Bay, Pearl River estuary

Deng,

Chen,

2023

Earth Surf Processes Landf

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A thorough understanding of the evolutionary trends of river bifurcation channels is crucial for effective estuarine management in China's Greater Bay Area due to significant morphological changes observed in river mouth channels. At this tide‐influenced river mouth, where suspended sediment transport is dominant, how river mouth bifurcated channels that have different angles to the major axis of the incoming tidal flow in the receiving basin evolve on decadal scales remains unclear. Based on a comparative analysis of historical bathymetric data and numerical experiments using a validated morphodynamic model, we developed a conceptual model to illustrate the two end members of the morphological evolution of river mouth channels: a low‐angle (<45°) main channel and a high‐angle (>45°) secondary channel relative to the major axis of tidal flow in the receiving basin. If the mouth outflow also has a low angle with the main channel, the incoming tidal discharge fluxes have first‐order control over changes in the evolutionary trend of the bifurcated channels by changing the partition of residual sediment discharges between the two bifurcated channels. For example, a high incoming tidal discharge that varies around the mean flow increases the partitioning of residual sediment discharges from the upstream channel to the low‐angle channel, facilitating tide‐induced erosion in the low‐angle channel. By contrast, a low incoming tidal discharge decreases the partitioning of residual sediment discharges from the upstream channel to the low‐angle channel, which facilitates fluvial‐induced erosion in the high‐angle channel. Thus, high tidal discharges usually coincide with the river mouth adopting a single channel, and low tidal discharges facilitate the formation of fluvial‐induced bifurcation. The historical evolution of the river mouth and modern velocity measurements corroborated results derived from model experiments. The conceptual model applies to river mouths where suspended sediment transport is dominant and influenced by angled incoming tides.

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Estuarine morphology and depositional processes in front of lateral river-dominated outlets in a tide-dominated estuary: A case study of the Lingding Bay, South China Sea

Cited by 10 publications

References 29 publications

Wave Effects on Sediment Transport and Entrapment in a Channel‐Shoal Estuary: The Pearl River Estuary in the Dry Winter Season

Wave Effects on Sediment Transport and Entrapment in a Channel‐Shoal Estuary: The Pearl River Estuary in the Dry Winter Season

Sea‐surface temperature anomalies mediate changes in fish richness and abundance in Atlantic and Gulf of Mexico estuaries

Asymmetric evolution of river mouth bifurcation under angled river‐tide interaction, a case study at river mouths of Lingding Bay, Pearl River estuary

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