Papers by Lotte Oosterlee
► Wetland plants colonized the metal contaminated site following restoration. ► Low metal pool in... more ► Wetland plants colonized the metal contaminated site following restoration. ► Low metal pool in the aboveground vegetation makes phytoextraction inapplicable. ► High Cd and Zn accumulation in willow trees may be of concern. ► Metal accumulation was lowest in aboveground tissues of large emergent macrophytes. ► Management which promotes macrophytes may reduce food chain contamination. a b s t r a c t a r t i c l e i n f o Accumulation of 8 metals and the semimetal As in 29 plant species was quantified in a restored tidal wetland on a contaminated site. Transfer coefficients between sediment and aboveground plant tissues were lower than in many other systems; from 0.013 (Pb) to 0.189 (Mn). A minor fraction of the sediment metal pool cycled through the aboveground vegetation (≤ 0.02%). However, during the four years of this study, species composition changed, and plant biomass as well as the metal pool in the vegetation increased (≤0.12%). Succession to either a willow dominated brus...
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In a CRT high inlet culverts and low outlet valves in the dike allow a limited amount of water to... more In a CRT high inlet culverts and low outlet valves in the dike allow a limited amount of water to enter and leave the low elevated polder area. The created tidal regime in the CRT has almost the same characteristics as the tidal regime on higher-elevated natural marshes in the estuary. In contrast, the SCS consists of a low single passage through the dike so that the full estuarine tidal range (on average 5.35 m) enters and leaves the low lying area without change of the tidal curve. It may be expected that in CRT-marshes or SCS-marshes the interaction between elevation change and consequent changes in tidal characteristics and soil properties deviate from each other and from natural tidal marshes. In this study we compare results on these variables between the systems and discuss possible underlying causes of the observed differences.
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CRT allows the implementation of a restricted tidal regime by the use of high inlet culverts and ... more CRT allows the implementation of a restricted tidal regime by the use of high inlet culverts and low outlet valves, as well as storm flood protection. Although the tidal amplitude is strongly reduced, the newly created marsh is subjected to flooding characteristics similar to the natural marshes in macrotidal estuaries. It allows the introduction of a wide range of flooding frequencies in a polder with an elevation far below the estuarine mean high water level. At the same time springneap tide variation is maintained, but the the hydroperiod is extended compared to natural marshes.
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Estuarine, Coastal and Shelf Science
Due to an increasing appreciation of the highly valuable ecosystem services of tidal marshes, an ... more Due to an increasing appreciation of the highly valuable ecosystem services of tidal marshes, an increasing number of projects are being implemented to re-introduce tides on formerly embanked land using a variety of ‘soft’ engineering techniques. However, the ecological development of the recreated tidal marshes largely depends on the design of the project, as this determines the hydro-geomorphological evolution. In this study we compare the hydrogeomorphological development in two marsh restoration projects in the Scheldt estuary (Belgium), one with a controlled reduced tidal exchange (CRT) and one with a full tidal exchange (FTE) between the marsh and adjacent estuary, based on ten years (CRT) and five years (FTE) of data on sedimentation/erosion rates, sediment properties and tidal characteristics. The results clearly show that the CRT technique strongly reduces the input of sediments, whereas larger water depths in the FTE led to extremely high sedimentation rates of 60 to 400 cm yr-1 in the first 2.5 months. The rapidly accreting sediments in the FTE consolidated much less than in the CRT and this poor sediment consolidation may have contributed to slower vegetation and benthos colonization in the FTE. This comparison of two different tidal systems can serve as an example to show the effect of different techniques to re-introduce tides on the creation of tidal marshes on low-lying areas. Depending on the tidal marsh development goals, different hydrologic regimes and thereby different sedimentation rates may be desired. For example, when the objective is to contribute to estuarine flood risk mitigation by creating and maintaining a high water buffering capacity in restored tidal marshes, a CRT system with low sedimentation rates is preferred. However, when the objective is to build up soil elevation, for example as an adaptation to sea level rise, the FTE technique as studied here could be a good way to trap sediments.
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Ecology and Society, 2016
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Estuaries and Coasts, 2017
Tidal marsh (re)creation on formerly embanked land is increasingly executed along estuaries and c... more Tidal marsh (re)creation on formerly embanked land is increasingly executed along estuaries and coasts in Europe and the USA, either by restoring complete or by reduced tidal exchange. Ecosystem functioning and services are largely affected by the hydro-geomorphologic development of these areas. For natural marshes, the latter is known to be steered by feedbacks between tidal inundation and sediment accretion, allowing marshes to reach and maintain an equilibrium elevation relative to the mean sea level. However, for marsh restoration sites, these feedbacks may be disturbed depending on the restoration design. This was investigated by comparing the inundation-elevation change feedbacks in a natural versus restoration site with reduced tidal exchange in the Scheldt estuary (Belgium). This study analyzes long-term (9 years) datasets on elevation change and tidal inundation properties to disentangle the different mechanisms behind this elevation-inundation feedback. Moreover, subsequent changes in sediment properties that may affect this feedback were explored. In the restoration area with reduced tidal exchange, we found a different elevation-inundation feedback than on natural marshes, which is a positive feedback on initially high sites (i.e., sediment accretion leads to increasing inundation, hence causing accelerating sediment accretion rates) and a gradual silting up of the whole area. Furthermore, there is evidence for the presence of a relict consolidated sediment layer. Consequently, shallow subsidence is less likely to occur. Although short-term ecological development of the tidal marsh was not impeded, long-term habitat development may be affected by the differences in hydro-geomorphological interactions. An increase of inundation frequency on the initially high sites may cause inhibition of habitat succession or even reversed succession. Over time, the climax state of the restoration area may be different compared to natural marshes. Moreover, sediment-related ecosystem services, such as nutrient and carbon burial, may be positively influenced because of continuing sedimentation, although flood water storage potential will decrease with increasing elevation. Depending on the restoration goals, ecosystem trajectories and delivery of ecosystem services can be controlled by adaptive management of the tidal volume entering the restoration area.
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Estuarine, Coastal and Shelf Science, 2019
Due to an increasing appreciation of the highly valuable ecosystem services of tidal marshes, an ... more Due to an increasing appreciation of the highly valuable ecosystem services of tidal marshes, an increasing number of projects are being implemented to re-introduce tides on formerly embanked land using a variety of ‘soft’ engineering techniques. However, the ecological
development of the recreated tidal marshes largely depends on the design of the project, as this determines the hydro-geomorphological evolution. In this study we compare the hydrogeomorphological development in two marsh restoration projects in the Scheldt estuary
(Belgium), one with a controlled reduced tidal exchange (CRT) and one with a full tidal exchange (FTE) between the marsh and adjacent estuary, based on ten years (CRT) and five years (FTE) of data on sedimentation/erosion rates, sediment properties and tidal characteristics. The results clearly show that the CRT technique strongly reduces the input of sediments, whereas larger water depths in the FTE led to extremely high sedimentation rates of 60 to 400 cm yr-1 in the first
2.5 months. The rapidly accreting sediments in the FTE consolidated much less than in the CRT and this poor sediment consolidation may have contributed to slower vegetation and benthos colonization in the FTE. This comparison of two different tidal systems can serve as an example to show the effect of different techniques to re-introduce tides on the creation of tidal marshes on low-lying areas. Depending on the tidal marsh development goals, different hydrologic regimes and thereby different sedimentation rates may be desired. For example, when the objective is to contribute to estuarine flood risk mitigation by creating and maintaining a high water buffering capacity in restored tidal marshes, a CRT system with low sedimentation rates is preferred. However, when the objective is to build up soil elevation, for example as an adaptation to sea level rise, the FTE technique as studied here could be a good way to trap sediments.
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Ecohydrology, 2014
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Science of The Total Environment, 2013
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Papers by Lotte Oosterlee
development of the recreated tidal marshes largely depends on the design of the project, as this determines the hydro-geomorphological evolution. In this study we compare the hydrogeomorphological development in two marsh restoration projects in the Scheldt estuary
(Belgium), one with a controlled reduced tidal exchange (CRT) and one with a full tidal exchange (FTE) between the marsh and adjacent estuary, based on ten years (CRT) and five years (FTE) of data on sedimentation/erosion rates, sediment properties and tidal characteristics. The results clearly show that the CRT technique strongly reduces the input of sediments, whereas larger water depths in the FTE led to extremely high sedimentation rates of 60 to 400 cm yr-1 in the first
2.5 months. The rapidly accreting sediments in the FTE consolidated much less than in the CRT and this poor sediment consolidation may have contributed to slower vegetation and benthos colonization in the FTE. This comparison of two different tidal systems can serve as an example to show the effect of different techniques to re-introduce tides on the creation of tidal marshes on low-lying areas. Depending on the tidal marsh development goals, different hydrologic regimes and thereby different sedimentation rates may be desired. For example, when the objective is to contribute to estuarine flood risk mitigation by creating and maintaining a high water buffering capacity in restored tidal marshes, a CRT system with low sedimentation rates is preferred. However, when the objective is to build up soil elevation, for example as an adaptation to sea level rise, the FTE technique as studied here could be a good way to trap sediments.
development of the recreated tidal marshes largely depends on the design of the project, as this determines the hydro-geomorphological evolution. In this study we compare the hydrogeomorphological development in two marsh restoration projects in the Scheldt estuary
(Belgium), one with a controlled reduced tidal exchange (CRT) and one with a full tidal exchange (FTE) between the marsh and adjacent estuary, based on ten years (CRT) and five years (FTE) of data on sedimentation/erosion rates, sediment properties and tidal characteristics. The results clearly show that the CRT technique strongly reduces the input of sediments, whereas larger water depths in the FTE led to extremely high sedimentation rates of 60 to 400 cm yr-1 in the first
2.5 months. The rapidly accreting sediments in the FTE consolidated much less than in the CRT and this poor sediment consolidation may have contributed to slower vegetation and benthos colonization in the FTE. This comparison of two different tidal systems can serve as an example to show the effect of different techniques to re-introduce tides on the creation of tidal marshes on low-lying areas. Depending on the tidal marsh development goals, different hydrologic regimes and thereby different sedimentation rates may be desired. For example, when the objective is to contribute to estuarine flood risk mitigation by creating and maintaining a high water buffering capacity in restored tidal marshes, a CRT system with low sedimentation rates is preferred. However, when the objective is to build up soil elevation, for example as an adaptation to sea level rise, the FTE technique as studied here could be a good way to trap sediments.