Role of eelgrass on bed‐load transport and sediment resuspension under oscillatory flow

Limnology and Oceanography, Journal Year: 2019, Volume and Issue: 65(2), P. 426 - 436

Published: Sept. 16, 2019

Abstract Coastal vegetation is widely attributed to stabilize sediment. While most studies focused on how canopy causes flow reduction and thereby affects sediment dynamics, the role of roots rhizomes stabilizing surface has been less well studied. This study aims quantify interactions between above‐ belowground biomass eelgrass (i.e., living Zostera marina plants mimics) with erosion bed load suspended load), under different hydrodynamic forcing that was created using a wave flume. Belowground played an important preventing bed‐load erosion, by roughly halving amount transported after being exposed maximal orbital velocities 27 cm s −1 , without canopy. Surprisingly, for transport, we found opposite effects. In presence eelgrass, critical threshold started at lower than bare sediment, including sand mud treatments. Moreover, in muddy systems, such resuspension reduced light level below minimum requirement Z. . surprising result ascribed too small patch reducing waves but rather showing enhanced turbulence scouring meadow edges. Overall, conclude conservation existent meadows developed stabilization scale should be taken into account decrease resuspension.

Language: Английский

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Quantifying Seasonal Seagrass Effects on Flow and Sediment Dynamics in a Back‐Barrier Bay

Journal of Geophysical Research Oceans, Journal Year: 2020, Volume and Issue: 126(2)

Published: Dec. 23, 2020

Abstract Seagrass growth and senescence exert a strong influence on flow structure sediment transport processes in coastal environments. However, most previous studies of seasonal seagrass effects either focused small‐scale field measurements or did not fully resolve the synergistic flow‐wave‐vegetation‐sediment interaction at meadow scale. In this study, we applied coupled Delft3D‐FLOW SWAN model that included flow, waves, resuspension shallow bay to quantify impacts dynamics. The was extensively validated using hydrodynamic suspended data within nearby unvegetated site. Our results show meadows significantly attenuated (60%) waves (20%) reduced concentration (85%) during summer when its density reached maximum. Probability distributions combined wave‐current bed shear stress indicate significant reductions were mainly caused by retardation rather than wave attenuation. Although low‐density winter resulted much smaller compared with meadows, small changes large differences magnitude attenuation stress. Similarly, while high densities effectively trapped summer, net flux into/out meadow. At our study site, low provided wintertime loss losses associated completely conditions.

Language: Английский

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Increased current flow enhances the risk of organic carbon loss fromZostera marinasediments: Insights from a flume experiment

Limnology and Oceanography, Journal Year: 2018, Volume and Issue: 63(6), P. 2793 - 2805

Published: Aug. 13, 2018

Abstract Hydrodynamic processes are important for carbon storage dynamics in seagrass meadows, where periods of increased hydrodynamic activity could result erosion and the loss buried carbon. To estimate impacts on resuspension organic (C org ) seagrass‐vegetated sediments, we exposed patches (0.35 × 0.35 cm) Zostera marina (with different biomass, shoot densities, sediment properties) to gradually unidirectional (current) flow velocities ranging from low (5 cm s −1 high (26 a hydraulic flume with standardized water column height 0.12 m. We found that higher substantially (by more than threefold) proportion C suspended resulting up 5.5% ± 1.7% (mean SE) surface sediment. This was presumably due larger, carbon‐rich detritus particles. Resuspension plots correlated properties (i.e., bulk density, porosity, sedimentary plant structure belowground biomass). However, density had no influence (comparing unvegetated sediments sparse, moderate, dense bed types), which be relatively experimental setup maximum 253 shoots m −2 reflecting natural conditions Swedish west coast. The projected increase frequency intensity forces climate change thus negatively affect function meadows as sinks.

Language: Английский

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Can pesticides, copper and seasonal water temperature explain the seagrass Zostera noltei decline in the Arcachon bay?

Marine Pollution Bulletin, Journal Year: 2017, Volume and Issue: 134, P. 66 - 74

Published: Oct. 26, 2017

Language: Английский

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Carbon storage and sediment trapping by Egeria densa Planch., a globally invasive, freshwater macrophyte

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 755, P. 142602 - 142602

Published: Oct. 2, 2020

Invasive plants have long been recognized for altering ecosystem properties, but their long-term impacts on processes remain largely unknown. In this study, we determined the impact of Egeria densa Planch, a globally invasive freshwater macrophyte, sedimentation in large tidal region. We measured carbon accumulation (CARs) and inorganic rates submerged aquatic vegetation SAV dominated by E. compared these to those adjacent marshes. Study sites were chosen along range hydrodynamic conditions Sacramento-San Joaquin Delta California, USA, where has widespread since 1990. Cores analyzed bulk density, % matter, organic carbon, 210Pb, 137Cs. Our results show that patches constitute sinks both "blue carbon" sediment. Compared marshes, greater (E. densa: 1103–5989 g m−2 yr−1, marsh: 393–1001 p < 0.01) vertical accretion 0.4–1.3 cm 0.3–0.5 0.05), similar CARs 59–242 C 109–169 > 0.05). Sediment stored likely reduces resilience marshes depleting sediment available marsh-building. Because its harmful traits, is not suitable candidate mitigating pollution; however, currently invaded habitats may already contain meaningful component regional budgets. strongly suggest are throughout global range, raising questions about how biogeochemical cycling dynamics across ecosystems.

Language: Английский

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Spatial sedimentation and plant captured sediment within seagrass patches

Marine Environmental Research, Journal Year: 2023, Volume and Issue: 188, P. 105997 - 105997

Published: April 23, 2023

Habitat degradation in coastal ecosystems has resulted the fragmentation of aquatic vegetation and compromised their role supplying essential ecological services such as trapping sediment or sequestering carbon. Fragmentation changed seagrass architecture by decreasing density canopy engendering small patches vegetated areas. This study aims to quantify different patch sizes with densities have spatial distribution within a patch. To this aim, two densities, four lengths, wave frequencies were considered. The amounts deposited onto bed, captured plant leaves, remaining suspension canopy, above used understand impact hydrodynamics on patterns patches. In all cases studied, reduced suspended concentrations, increased capture particles sedimentation rates bed. For lowest frequency studied (0.5 Hz), bottom was enhanced at edges, resulting heterogeneous patterns. Therefore, restoration preservation landscapes can help face future climate change scenarios where an increase mitigate predicted sea level rise

Language: Английский

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Stochastic Simulation of the Suspended Sediment Deposition in the Channel With Vegetation and Its Relevance to Turbulent Kinetic Energy

Water Resources Research, Journal Year: 2021, Volume and Issue: 57(9)

Published: Aug. 30, 2021

Abstract The aquatic vegetation patch plays a significant role on sediment net deposition in the vegetated channels. Particularly, flow is decelerated at leading edge of that tends to induce vertical updraft, is, diverging region, which greatly affects pattern deposition. This study focuses simulation whole region through an innovative random displacement model, Lagrange method, with probability‐based boundary conditions, instead reflection or sorption channel bottom. probability model and resuspension proposed according field characteristics different regions patch. variation turbulent kinetic energy analyzed illustrate effect turbulence induced by vegetation, represented dimensionless ( ψ ), resuspension. predicted agrees well experimental measurements. Results show motions begins prevail when vegetation‐induced larger than its threshold, * . threshold be within 6.8–10 results this study. As increases, decreases continuously >

Language: Английский

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Role of suspended particulate material on growth and metal bioaccumulation in oysters (Crassostrea gigas) from a French coastal semi-enclosed production area, Arcachon Bay

Journal of Marine Systems, Journal Year: 2022, Volume and Issue: 234, P. 103778 - 103778

Published: June 30, 2022

Language: Английский

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Contextualising shoreline protection by seagrass using lessons from submerged breakwaters

Estuarine Coastal and Shelf Science, Journal Year: 2022, Volume and Issue: 276, P. 108011 - 108011

Published: Aug. 13, 2022

Language: Английский

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Environmental factors controlling biomass development of seagrass meadows of Zostera noltei after a drastic decline (Arcachon Bay, France)

Journal of Sea Research, Journal Year: 2018, Volume and Issue: 140, P. 87 - 104

Published: July 23, 2018

Language: Английский

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