scholarly journals Long-term and large-scale variability in productivity of the tellinid bivalve Macoma balthica on Wadden Sea tidal flats

2007 ◽  
Vol 337 ◽  
pp. 117-134 ◽  
Author(s):  
R Dekker ◽  
JJ Beukema
Keyword(s):  
Large Scale ◽  
Wadden Sea ◽  
Macoma Balthica ◽  
Tidal Flats

scholarly journals Effects of Waves and Sediment Disturbance on Seed Bank Persistence at Tidal Flats

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhenchang Zhu ◽  
Tjeerd J. Bouma ◽  
Qin Zhu ◽  
Yanpeng Cai ◽  
Zhifeng Yang
Keyword(s):  
Climate Change ◽  
Seed Bank ◽  
Large Scale ◽  
Environmental Changes ◽  
Tidal Flats ◽  
Coastal Vegetation ◽  
Climate Change Effects ◽  
Sediment Disturbance ◽  
Seed Bank Dynamics

Coastal wetlands such as salt marshes have been increasingly valued for their capacity to buffer global climate change effects, yet their long-term persistence is threatened by environmental changes. Whereas, previous studies largely focused on lateral erosion risk induced by stressors like sea level rise, it remains poorly understood of the response of lateral expansion to changing environments. Seedling establishment is a key process governing lateral marsh expansion as seen in many coastal regions such as Europe and East Asia. Here, we evaluate mechanistically the response of seed bank dynamics to changing physical disturbance at tidal flats, using the globally common coastal foundation plant, cordgrass as a model. We conducted a large-scale field study in an estuary in Northwest Europe, where seed bank dynamics of cordgrass in the tidal flats was determined and linked to in situ hydrodynamics and sediment dynamics. The results revealed that wave disturbance reduced the persistence of seeds on the surface, whereas amplified sediment disturbance lowered the persistence of both surface and buried seeds. Overall, this indicates that increasing storminess and associated sediment variability under climate change threatens seed bank persistence in tidal flats, and hence need urgently be incorporated into models for long-term bio-geomorphological development of vegetated coastal ecosystems. The knowledge gained here provides a basis for more accurate predictions on how climatically driven environmental changes may alter the fitness, resilience and persistence of coastal foundation plants, with significant implications for nature-based solutions with coastal vegetation to mitigate climate change effects.

scholarly journals Sediment budget and morphological development of the Dutch Wadden Sea: impact of accelerated sea-level rise and subsidence until 2100

2018 ◽  
Vol 97 (3) ◽  
pp. 183-214 ◽  
Author(s):  
Zheng Bing Wang ◽  
Edwin P.L. Elias ◽  
Ad J.F. van der Spek ◽  
Quirijn J. Lodder
Keyword(s):  
Sea Level ◽  
Wadden Sea ◽  
Barrier Islands ◽  
Tidal Flats ◽  
Morphological Development ◽  
Tidal Channels ◽  
The North ◽  
Tidal Basins ◽  
The North Sea

AbstractThe Wadden Sea is a unique coastal wetland containing an uninterrupted stretch of tidal flats that span a distance of nearly 500km along the North Sea coast from the Netherlands to Denmark. The development of this system is under pressure of climate change and especially the associated acceleration in sea-level rise (SLR). Sustainable management of the system to ensure safety against flooding of the hinterland, to protect the environmental value and to optimise the economic activities in the area requires predictions of the future morphological development.The Dutch Wadden Sea has been accreting by importing sediment from the ebb-tidal deltas and the North Sea coasts of the barrier islands. The average accretion rate since 1926 has been higher than that of the local relative SLR. The large sediment imports are predominantly caused by the damming of the Zuiderzee and Lauwerszee rather than due to response to this rise in sea level. The intertidal flats in all tidal basins increased in height to compensate for SLR.The barrier islands, the ebb-tidal deltas and the tidal basins that comprise tidal channels and flats together form a sediment-sharing system. The residual sediment transport between a tidal basin and its ebb-tidal delta through the tidal inlet is influenced by different processes and mechanisms. In the Dutch Wadden Sea, residual flow, tidal asymmetry and dispersion are dominant. The interaction between tidal channels and tidal flats is governed by both tides and waves. The height of the tidal flats is the result of the balance between sand supply by the tide and resuspension by waves.At present, long-term modelling for evaluating the effects of accelerated SLR mainly relies on aggregated models. These models are used to evaluate the maximum rates of sediment import into the tidal basins in the Dutch Wadden Sea. These maximum rates are compared to the combined scenarios of SLR and extraction-induced subsidence, in order to explore the future state of the Dutch Wadden Sea.For the near future, up to 2030, the effect of accelerated SLR will be limited and hardly noticeable. Over the long term, by the year 2100, the effect depends on the SLR scenarios. According to the low-end scenario, there will be hardly any effect due to SLR until 2100, whereas according to the high-end scenario the effect will be noticeable already in 2050.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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