Zeng Zhou

• Doctor of Philosophy
• Professor (Full) at Hohai University

Dear Colleagues, Submarine and coastal geomorphology play a fundamental role in revealing the basic characteristics, evolution, and dynamical processes of the seafloor, serving as a foundation for submarine geosciences. From shallow coasts to the deep sea, the seafloor exhibits a wide range of forms, reflecting the influence of a range of oceanogr...

Introduction Saltmarsh introduction has been widely implemented to restore ecosystem services and promote sedimentation in tidal mudflats, yet its effects on tidal network dynamics remain hard to predict. The interplay between saltmarsh extent and sediment availability in shaping long-term mudflat morphodynamics is not fully understood. Methods We...

The limited space for coastal wetland conservation may conflict with achieving the 30 % protected area target under the Kunming-Montreal Global Biodiversity Framework. Identifying ecological corridors and enhancing connectivity in coastal wetlands is crucial for prioritizing critical areas. Our study presents a methodology for identifying ecologica...

Coastal salt marsh wetlands are crucial reservoirs of soil carbon (C) and nitrogen (N). However, the effects of plant type, geomorphology, and macrobenthos on spatial variations in soil C and N in coastal wetlands remain unclear. In this study, the spatial distribution of soil C and N components was investigated in a coastal wetland (Jiuduansha Sho...

Branching networks are key elements in natural landscapes and have attracted sustained research interest across the geosciences and numerous intersecting fields. The prevailing consensus has long held that branching networks are optimized and exhibit fractal properties adhering to power-law scaling relationships. However, tidal networks in coastal...

Mangrove‐saltmarsh ecotones are experiencing rapid alterations due to climate change and human activities, however, the ecological and morphological implications of these shifts remain largely unknown. This study systematically explores how interspecific interactions and herbivory influence the dominant wetland species, as well as the resultant mor...

Introduction Tidal marsh wetlands provide essential and valuable services to the wider interconnected marine and coastal environment, although the complex intertwined processes in morphological evolution remain insufficiently understood owing to synchronized data scarcity, limiting the development of numerical models and management strategies. Met...

Parallel tidal channel systems, characterized by commonly cross-shore orientation and regular spacing, represent a distinct class of tidal channel networks in coastal environments worldwide. Intriguingly, these cross-shore oriented channel systems can develop in environments dominated by alongshore tidal currents, for which the mechanisms remain el...

The ocean, Earth's largest carbon sink, plays a critical role in studying the carbon cycle in estuarine and coastal environments, making the retrieval of dissolved organic carbon (DOC) content highly significant. Machine learning retrieval techniques outperform traditional band ratio methods in handling high-dimensional and nonlinear features. Howe...

Tidal channel systems arising from morphodynamic interactions exhibit a suite of diverse morphological configurations. A prevalent type is represented by linear dendritic channels formed by single-thread streams aligned roughly parallel or subparallel to each other in the cross-shore direction. Despite their ubiquity, the processes driving the form...

Salt marshes are among the most important coastal wetlands and provide critical ecological services, including climate regulation, biodiversity maintenance, and blue carbon sequestration. However, most salt marshes worldwide are shrinking, owing to the effects of natural and human factors, such as climate change and artificial reclamation. Therefor...

A series of laboratory experiments have been conducted to explore the wind effect on Sediment Suspended Concentrations (SSCs) in fine-grained coastal systems. The paddle waves were overplayed with surface-blowing winds in a wind-wave flume to mimic offshore swells coupling with local wind waves during rough weather. Both SSCs and water turbulences...

Crab burrows play an important role in saltmarsh wetlands and are a useful indicator of wetland condition. The spatiotemporal distribution of crab burrows varies considerably in tidal wetlands. However, the reasons for these variations are poorly understood, in part, due to the limited availability of comprehensive field data. Based on a two-year c...

This research demonstrates how the effect of exposure to air on intertidal flat profile development in cohesive coastal environments can be incorporated into applied numerical modelling. Semi-empirical relationships were used to include the sediment stabilizing effects of exposure on changes to the erosion threshold (Ƭcr; N m−2) and erosion rate (E...

Crab burrows play an important role in saltmarsh wetlands and are a useful indicator of wetland condition. The spatiotemporal distribution of crab burrows varies considerably in tidal wetlands. However, the reasons for these variations are poorly understood, in part, due to the limited availability of comprehensive field data. Based on a two-year c...

Field studies suggest that storms can considerably affect the morphology, sedimentology and bedding structure of tidal flat wetlands because of their high-energy, while numerical modeling studies unravelling the underlying mechanisms remain rare. With a tidal flat of the Changjiang Delta, China as a reference site, this study explores the role of s...

Estuarine mudflats are profoundly affected by increased coastal erosion and reduced sediment delivery from major rivers. Although managers are having difficulties to control the cause of increased coastal erosion, they can help to manage the resilience of mudflat ecosystems to erosion through river flow regulation. In this study, we associated the...

Tidal flats and saltmarshes have been a long-standing research focus because of their high socio-economic and ecological values. The evolution of tidal flat–marsh systems is highly complex due to the intertwined processes operating over a variety of spatial and temporal scales. As a traditional research highlight, the role of regular hydrodynamic p...

Mangrove forests are valuable coastal ecosystems that have been shown to persist on muddy intertidal flats through bio‐morphodynamic feedbacks. However, the role of coastal conditions on mangrove behavior remains uncertain. This study conducts numerical experiments to systematically explore the effects of tidal range, small wind waves, sediment sup...

Researchers have extensively investigated the back-barrier islands morphodynamics using numerical methods. However, the influence of rocky mouth islands, which may be submerged by sea-level rise, has been rarely explored. Using the Dongshan Bay in southern China as a reference, this study numerically explores the long-term morphodynamic effect of g...

It is common to obtain the topography of tidal flats by the Unmanned Aerial Vehicle (UAV) photogrammetry, but this method is not applicable in tidal creeks. The residual water will lead to inaccurate depth inversion results, and the topography of tidal creeks mainly depends on manual survey. The present study took the tidal creek of Chuandong port...

The salt marsh system on the tidal flat is one of the most productively ecological wetlands with high biological productivity and blue carbon sequestration levels. The evolution of salt marshes-bare flats boundaries and the shapes of salt marsh margins are of scientific and engineering prospects due to the capability on indicating the morphodynamic...

ContextAnimal movements influence the spatial heterogeneity of variously ecosystem processes. However, our understand of how movement in heterogeneous landscapes shapes ecological process were derived mostly from models assuming that landscape is static over time, which might mask more complex interactions and important consequences.Objectives We t...

The use of power law forms to describe hydraulic geometry is a classic subject with a history of over 70 years. Two distinct forms of power laws have been proposed: at-a-station hydraulic geometry (AHG) and downstream hydraulic geometry (DHG). Although the utility of these semiempirical expressions is widely recognized, they remain poorly understoo...

The morphodyamics of back-barrier tidal basins have been extensively investigated by numerical modelling, but the influence of mouth islands (which may be submerged under future sea level rise) has been rarely explored. Using the Dongshan Bay in southern China as a reference site, we explore numerically the effects of geological constraints (i.e.,...

Understanding sediment sorting and bedding dynamics has high value to unravelling the mechanisms underlying geomorphological, geological, ecological and environmental imprints of tidal wetlands and hence to predicting their future changes. Using the Nanhui tidal flat on the Changjiang (Yangtze) Delta, China, as a reference site, this study establis...

Water turbidity is of particular importance for diffusion and migration of nutrients and contaminants, biological production, and ecosystem health in coastal turbid areas. The estimation of water turbidity is therefore significant for studies of coastal dynamics. Many factors influence turbidity in complex and nonlinear ways, making accurate estima...

The landscape setting of estuaries varies widely and is an important aspect of determining how they evolve. This paper focusses on alluvial estuaries in river valleys and how they respond to sea level rise. We examine the implications of marine transgression, as a response to sea level rise, where the estuary moves upwards and landwards to maintain...

Mangrove forests are valuable ecosystems, but their extent and diversity are increasingly threatened by sea-level rise and anthropogenic pressures. Here we develop a bio-morphodynamic model that captures the interaction between multiple mangrove species and hydro-sedimentary processes across a dynamic coastal profile. Numerical experiments are cond...

The description of the geomorphic characteristics in power law forms has been the subject of research, over the past 70 years, and has become the cornerstone of regime theory. However, just why power functions should represent such geomorphic relationships remains poorly understood. Hence, differences in the values of the regime exponents observed...

The morphodynamic responses of tidal networks to anthropogenic reclamation and de-reclamation projects are investigated through a three-stage numerical simulation. In the first stage, the natural development of tidal networks is modelled in an open coast without any anthropogenic interventions. At the beginning of the second stage, parts of the com...

Dai, W.Q.; Li, H.; Chen, X.D.; Xu, F.; Zhou Z.; and Zhang, C.K., 2020. Saltmarsh expansion in response to morphodynamic evolution: Field observations in the Jiangsu coast using UAV. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 433–437. Coconut Creek (Florida), ISSN 0749...

Chen, L.; Zhou, Z.; Xu, F.; Möller, I., and Zhang, C.K., 2020. Field observation of saltmarsh-edge morphology and associated vegetation characteristics in an open-coast tidal flat. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 412–416. Coconut Creek (Florida), ISSN 0749-...

We set up a laboratory experiment to reproduce flow‐induced bank erosion and bank collapse and to study the role of bank height (Hb) and near‐bank water depth (Hw) on bank stability. Five laboratory experiments were conducted in a plexiglass‐walled soil tank, using silt collected from natural tidal channel banks (D50 = 75 μm). During each experimen...

Salinity difference between terrestrial river discharge and oceanic tidal water plays a role in modifying the local flow field and, as a consequence, estuarine morphodynamics. Although widely recognized, recent numerical studies exploring the long‐term morphological evolution of river‐influenced estuaries with two‐dimensional, depth‐averaged models...

We develop a process-based model to simulate the geomorphodynamic evolution of tidal channels, considering hydrodynamics, flow-induced bank erosion, gravity-induced bank collapse, and sediment dynamics. A stress-deformation analysis and the Mohr-Coulomb criterion, calibrated through previous laboratory experiments, are included in a model simulatin...

Flood and ebb currents provide different contributions to the initiation and evolution of tidal channel networks, generating diverse network structures and channel cross‐sections. In order to separate the effects of these contributions, a physical model of a sloping tidal‐flat basin was set up in the laboratory. Depending on the degree of tidal asy...

The radial sand ridges (denoted as “RSRs” hereafter) in the Southern Yellow Sea, China, are morphologically striking because of the remarkable size and radial planar orientation, standing out as a unique coastal geomorphology among the worldwide sand ridge systems. The formation of this giant fan‐shaped geomorphic feature requires delicate conditio...

We set up a two‐dimensional modeling framework to explore the development and the equilibrium configuration of a tidal channel. We consider two types of morphodynamic modeling systems coupling different flow and sedimentation models, to study the feedback mechanisms controlling the morphodynamics of tidal channels. The simulations indicate that the...

A state-of-the-art morphodynamic model (Delft3D) was used to explore the effects of bathymetric perturbation on the morphodynamic modeling of tidal channels and flats. Short-term and medium-term modeling results indicate that the two-way interaction of the hydrodynamic forcing and initial perturbation has influence on the evolution of tidal channel...

We explore the effects of land reclamation on the morphological evolution and sediment sorting on a tidal flat using a state-of-the-art numerical model (Delft3D). Consistent with existing field observations and analytical theories, model results indicate that the longitudinal profile adjusts itself converging to new equilibrium states (narrower and...

To explore the evolution mechanism of tidal flats under the influence of multiple factors, a cross-shore profile numerical model is developed based on vegetation growth and tidal processes. For a bare flat driven by tides, a general convex cross-shore profile is obtained after medium-to long-term simulation. Sediment supply determines the width of...

This paper presents a new model, using existing consolidation theory, suitable for long-term morphodynamic simulations; we refer to the dynamic equilibrium consolidation (DECON) model. This model is applicable for muddy systems at small suspended particulate matter (SPM) concentrations, where the sedimentation rates are smaller than the consolidati...

Tidal flats are fragile and delicate. Studies show that anthropogenic pressures and sea level rise due to climate changes have an effect and play a vital role in the morphodynamics of tidal flats worldwide. It is very important to understand the regularities and morphodynamic variations of tidal flats whilst investigating the external condition res...

The research objective is to clarify the primary factors lead to the variations of the suspended sediment transport in the radial sand ridges (RSRs) along the Jiangsu Coast over the last 30 years. The suspended sediment concentration (SSC) fields measured in several field surveys from 1980 to 2010 were analyzed. The field data indicate that the SSC...

The cross-shore profile shape and sediment sorting of tidal flats play an important role in the research of estuarine and coastal morphodynamics, and bear practical significance for maintaining biodiversity, exploring sedimentation history, and assessing the impacts of coastal engineering projects. This study reviews the advancements in the researc...

Biofilms, consisting of microorganisms and their secreted extracellular polymeric substances (EPSs), serve as “ecosystem engineers” stabilizing sedimentary environments. Natural sediment bed provides an excellent substratum for biofilm growth. The porous structure and rich nutrients allow the EPS matrix to spread deeper into the bed. A series of la...

The long-term morphodynamic evolution of tidal networks on tidal flats is investigated using a two-dimensional numerical model. We explore the physical processes related to the development of the morphology and the presence of equilibrium configurations. Tidal networks are simulated over a rectangular domain representing a tidal platform, a differe...

Simple stability relationships are practically useful to provide a rapid assessment of coastal and estuarine landforms in response to human interventions and long‐term climate change. In this contribution, we review a variety of simple stability relationships which are based on the analysis of tidal asymmetry (shortened to “TA”). Most of the existi...

Fifteen monthly field surveys were conducted from September 2012 to November 2013 at ten representative stations along a cross-shore profile, covering the entire tidal flat. Results indicate that tidal currents significantly affect bed level variations over bare flats, while subsurface processes (e.g., soil subsidence and expansion) are likely to p...

Extracellular polymeric substances (EPS) are ubiquitous on tidal flats but their impact on sediment erosion has not been fully understood. Laboratory-controlled sediment beds were incubated with Bacillus subtilis for 5, 10, 16 and 22 days before the erosion experiments, to study the temporal and spatial variations in sediment stability caused by th...

To explore the initiation and development of tidal creek network driven by tidal currents, an experimental physical model was established based on the prototype of a silt-muddy tidal flat-creek system on the Jiangsu coast. The evolutional process was simulated with an initially gentle bed slope of about 1%. The movement of flow and sediment, as wel...

Morphodynamic equilibrium is a widely adopted yet elusive concept in the field of geomorphology of coasts, rivers and estuaries. Based on the Exner equation, an expression of mass conservation of sediment, we distinguish three types of equilibrium defined as static and dynamic, of which two different types exist. Other expressions such as statistic...

To deepen the understanding of the dynamics underlying tidal creek evolution, a reduced-scale physical model was established based on the prototype of muddy silt tidal flat-creek system on the central Jiangsu coast. Driven by tidal currents, the evolution of tidal creeks was simulated starting from initial uniform bed level to a dynamic equilibrium...

Whilst much attention has been given to models that describe wave, tide and sediment transport processes in sufficient detail to determine the local changes in bed level over a relatively detailed representation of the bathymetry, far less attention has been given to models that consider the problem at a much larger scale (e.g. that of geomorpholog...

Taking a channel downstream the Sheyang sluice as a prototype, a two-dimensional generalized morphodynamic model is established to investigate the siltation mechanism of a typical channel downstream floodgate in muddy coasts, China. The influence of runoff on hydro-sediment dynamics, as well as the souring and silting evolution in the channel, has...

Whilst much attention has been given to models that describe wave, tide and sediment transport processes in sufficient detail to determine the local changes in bed level over a relatively detailed representation of the bathymetry, far less attention has been given to models that consider the problem at a much larger scale (e.g. that of geomorpholog...

Intertidal mudflats are often characterized by a special “very shallow water” environment, with a water depth in the order of 10 cm. High-resolution data including water depth, wave parameters, velocity profiles (within 3–6 cm above the mudflat surface with a vertical resolution as fine as 1 mm), stratified suspended sediment concentration (SSC) an...

Radial sand ridges (RSRs) spread in a fan-shaped pattern over the seabed of the southern Yellow Sea along the Jiangsu Coast (China) with pronounced differences between the northern and southern channel-shoals (indicated as "NCS" and "SCS", respectively). A depth-averaged nested numerical model is employed to analyze the tidal hydrodynamics and sedi...

Bank erosion of tidal creeks are chiefly driven by flow incision and gravity-induced collapse subprocesses. Depth-to-width ratio, the geometric characterisics of tidal creeks, has been extensively investigated by numerical simulations. However, bank collapse process has less been taken into account in previous numerical models. In this study, a num...

We develop a biomorphodynamic model to investigate sediment and vegetation dynamics on a schematic intertidal flat characterized by an initially well-mixed sand-mud mixture. Major interactions between tides, wind waves, salt marshes, sediment transport and sea level rise (SLR) are taken into account. For a bare flat under only tidal action, the mod...

We extend a numerical model to explore the morphodynamics of intertidal flats, with a specific focus on the sorting dynamics of sand and mud. We investigate the effect of tidal currents, wind waves, sediment properties, external sediment supply, flocculation and initial bed composition on the cross-shore profile shape and sediment sorting of intert...

The bed elevation of mudflats is governed by both surface processes (e.g., sediment deposition and erosion) and subsurface processes (e.g., soil consolidation and organic matter accumulation). An improved RSET-MH (Rod Surface Elevation Table-Marker Horizon) facility was introduced for the field measurement of surface accretion, subsurface soil cons...

We investigate the morphodynamics of river-influenced barrier basins numerically, with a particular emphasis on the effects of landscape and hydrodynamic settings. The simulated morphologies are qualitatively comparable to natural systems (e.g., tidal inlets along the East Coast of the U.S.). Model results suggest that the basin morphology is gover...