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H L Rees - One of the best experts on this subject based on the ideXlab platform.
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the effects of marine sand and Gravel Extraction on the macrobenthos at a commercial dredging site results 6 years post dredging
Ices Journal of Marine Science, 2005Co-Authors: S.e. Boyd, H L Rees, David S Limpenny, Keith M CooperAbstract:Boyd, S. E., Limpenny, D. S., Rees, H. L., and Cooper, K. M. 2005. The effects of marine sand and Gravel Extraction on the macrobenthos at a commercial dredging site (results 6 years post-dredging). e ICES Journal of Marine Science, 62: 145e162. Benthic recolonization was investigated at a site historically used for the Extraction of marine sand and Gravel. The main objective was to assess the effects of different levels of dredging intensity on the recolonization of benthic fauna and sediments. Preliminary observations from this study indicated that the fauna within an area of seabed exposed to high dredging intensities remained in a perturbed state some 4 years after the cessation of dredging. Thereafter, annual monitoring surveys of the benthos and sediments at the ‘‘treatment’’ and ‘‘reference’’ sites have followed the recolonization process. Results from univariate and multivariate data analyses show that distinct differences in the nature of assemblages at sites exposed to high and lower levels of dredging intensity persist at least 6 years after the cessation of dredging. This paper presents the physical and biological findings 6 years after dredging, together with a generic framework for evaluating postcessation recolonization studies.
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the effects of marine Gravel Extraction on the macrobenthos results 2 years post dredging
Marine Pollution Bulletin, 1996Co-Authors: Andrew Kenny, H L ReesAbstract:Abstract An offshore experimental dredging study was initiated off North Norfolk (UK) in 1992 to investigate the impacts of marine Gravel Extraction on the macrofauna. A dredged ‘treatment’ and a non-dredged ‘reference’ site were selected to evaluate the initial impacts and subsequent processes of recolonization. A survey of the benthos was conducted prior to the removal of 50 000 t of marine aggregate from the treatment site. Thereafter annual monitoring surveys were conducted commencing immediately after the dredging episode. Results indicated that whilst the dominant species recolonized quickly following dredging many rarer species did not. Evidence from sidescan sonar records and underwater cameras indicated a considerable amount of sediment transport during the first two winters following dredging and the once well-defined dredge tracks have now become infilled with sand and Gravel. The substantially reduced biomass at the treatment site some 24 months after dredging is thought to be due to a local increase in sediment disturbance caused by tide and wave action over the winter period. Finally, the biological findings of this study are discussed in relation to their wider environmental significance.
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the effects of marine Gravel Extraction on the macrobenthos early post dredging recolonization
Marine Pollution Bulletin, 1994Co-Authors: Andrew Kenny, H L ReesAbstract:Abstract A small area of sea bed off the English east coast was experimentally dredged by a commercial suction-trailer dredger. Some 50 000 t of mixed aggregate were removed, representing about 70% of the sea bed area down to an average depth of 0.3 m. Results from benthic surveys undertaken at the experimental site and at a nearby reference site, indicate that significant reductions had occurred in the variety, abundance and biomass of benthic organisms as a consequence of dredging. Subsequent recolonization of dunuded substrates by the dominant taxa proceeded relatively rapidly, although the dredged site had clearly not fully recovered some 7 months later. Differences in the recruitment success of the dominant taxa, notably Dendrodoa grossularia and Balanus crenatus, between the reference and treatment sites pre- and post-dredging were observed. Possible explanations for these differences in relation to the observed physical alterations to the sea bed are discussed.
Keith M Cooper - One of the best experts on this subject based on the ideXlab platform.
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The effects of marine sand and Gravel Extraction on the sediment composition and macrofaunal community of a commercial dredging site (15 years post-dredging).
Marine pollution bulletin, 2015Co-Authors: Georgia A Waye-barker, Paul Mcilwaine, Sophie Lozach, Keith M CooperAbstract:A prediction that faunal recovery of a marine aggregate Extraction site subjected to high dredging intensity was likely to take 15-20 years was investigated. Samples were collected at the high dredging intensity site and two reference sites in 2011 (15 years post-dredging). Results indicated that the high site had similar sediment characteristics to the reference sites by 2011. Macrofaunal data analyses showed no difference between the values of all calculated univariate measures (abundance, number of taxa, biomass and evenness) between the high and reference sites. Multivariate analyses found that the macrofaunal community at the high site was comparable to those of the reference sites by 2011. Overall, the results supported the predicted recovery time. The findings of the study suggest that persistent physical impacts prolonged the biological recovery of the high site.
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the effects of marine sand and Gravel Extraction on the macrobenthos at a commercial dredging site results 6 years post dredging
Ices Journal of Marine Science, 2005Co-Authors: S.e. Boyd, H L Rees, David S Limpenny, Keith M CooperAbstract:Boyd, S. E., Limpenny, D. S., Rees, H. L., and Cooper, K. M. 2005. The effects of marine sand and Gravel Extraction on the macrobenthos at a commercial dredging site (results 6 years post-dredging). e ICES Journal of Marine Science, 62: 145e162. Benthic recolonization was investigated at a site historically used for the Extraction of marine sand and Gravel. The main objective was to assess the effects of different levels of dredging intensity on the recolonization of benthic fauna and sediments. Preliminary observations from this study indicated that the fauna within an area of seabed exposed to high dredging intensities remained in a perturbed state some 4 years after the cessation of dredging. Thereafter, annual monitoring surveys of the benthos and sediments at the ‘‘treatment’’ and ‘‘reference’’ sites have followed the recolonization process. Results from univariate and multivariate data analyses show that distinct differences in the nature of assemblages at sites exposed to high and lower levels of dredging intensity persist at least 6 years after the cessation of dredging. This paper presents the physical and biological findings 6 years after dredging, together with a generic framework for evaluating postcessation recolonization studies.
Andrew Kenny - One of the best experts on this subject based on the ideXlab platform.
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the effects of marine Gravel Extraction on the macrobenthos results 2 years post dredging
Marine Pollution Bulletin, 1996Co-Authors: Andrew Kenny, H L ReesAbstract:Abstract An offshore experimental dredging study was initiated off North Norfolk (UK) in 1992 to investigate the impacts of marine Gravel Extraction on the macrofauna. A dredged ‘treatment’ and a non-dredged ‘reference’ site were selected to evaluate the initial impacts and subsequent processes of recolonization. A survey of the benthos was conducted prior to the removal of 50 000 t of marine aggregate from the treatment site. Thereafter annual monitoring surveys were conducted commencing immediately after the dredging episode. Results indicated that whilst the dominant species recolonized quickly following dredging many rarer species did not. Evidence from sidescan sonar records and underwater cameras indicated a considerable amount of sediment transport during the first two winters following dredging and the once well-defined dredge tracks have now become infilled with sand and Gravel. The substantially reduced biomass at the treatment site some 24 months after dredging is thought to be due to a local increase in sediment disturbance caused by tide and wave action over the winter period. Finally, the biological findings of this study are discussed in relation to their wider environmental significance.
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the effects of marine Gravel Extraction on the macrobenthos early post dredging recolonization
Marine Pollution Bulletin, 1994Co-Authors: Andrew Kenny, H L ReesAbstract:Abstract A small area of sea bed off the English east coast was experimentally dredged by a commercial suction-trailer dredger. Some 50 000 t of mixed aggregate were removed, representing about 70% of the sea bed area down to an average depth of 0.3 m. Results from benthic surveys undertaken at the experimental site and at a nearby reference site, indicate that significant reductions had occurred in the variety, abundance and biomass of benthic organisms as a consequence of dredging. Subsequent recolonization of dunuded substrates by the dominant taxa proceeded relatively rapidly, although the dredged site had clearly not fully recovered some 7 months later. Differences in the recruitment success of the dominant taxa, notably Dendrodoa grossularia and Balanus crenatus, between the reference and treatment sites pre- and post-dredging were observed. Possible explanations for these differences in relation to the observed physical alterations to the sea bed are discussed.
Jean-luc Locht - One of the best experts on this subject based on the ideXlab platform.
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Fluvial deposits as an archive of early human activity: Progress during the 20 years of the Fluvial Archives Group
Quaternary Science Reviews, 2017Co-Authors: Parth R. Chauhan, David R. Bridgland, Marie-hélène Moncel, Pierre Antoine, Jean-jacques Bahain, Rebecca Briant, Pedro P. Cunha, Jackie Despriée, Nicole Limondin-lozouet, Jean-luc LochtAbstract:Fluvial sedimentary archives are important repositories for Lower and Middle Palaeolithic artefacts throughout the ‘Old World’, especially in Europe, where the beginning of their study coincided with the realisation that early humans were of great antiquity. Now that many river terrace sequences can be reliably dated and correlated with the globally valid marine isotope record, potentially useful patterns can be recognized in the distribution of the find-spots of the artefacts that constitute the large collections that were assembled during the years of manual Gravel Extraction. This paper reviews the advances during the past two decades in knowledge of hominin occupation based on artefact occurrences in fluvial contexts, in Europe, Asia and Africa. As such it is an update of a comparable review in 2007, at the end of IGCP Project no. 449, which had instigated the compilation of fluvial records from around the world during 2000–2004, under the auspices of the Fluvial Archives Group. An overarching finding is the confirmation of the well-established view that in Europe there is a demarcation between handaxe making in the west and flake–core industries in the east, although on a wider scale that pattern is undermined by the increased numbers of Lower Palaeolithic bifaces now recognized in East Asia. It is also apparent that, although it seems to have appeared at different places and at different times in the later Lower Palaeolithic, the arrival of Levallois technology as a global phenomenon was similarly timed across the area occupied by Middle Pleistocene hominins, at around 0.3 Ma.
F. Bureau - One of the best experts on this subject based on the ideXlab platform.
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Use of dredged sediments for soil creation in the Seine estuary (France): Importance of a soil functioning survey to assess the success of wetland restoration in floodplains
Ecological Engineering, 2014Co-Authors: Chokri Mchergui, M. Aubert, Bruno Buatois, M. Akpa-vinceslas, E. Langlois, C. Bertolone, R. Lafite, S. Samson, F. BureauAbstract:The creation and restoration of new wetlands to mitigate wetland losses is a newly developing science whose success still needs to be assessed. This study focuses on the ecological restoration of a Gravel-pit in the low valley of the Seine estuary (France). Restoration consisted in filling the Gravel-pit using a hydraulic technique with dredged sediments from the Seine river and covering it with alkaline peat from adjacent wet meadows. Our objectives were to survey the functions of recreated soil 3 years after the Gravel-pit was filled and assess whether it regained typical wetland functionality and to determine which soil functioning parameters are the most efficient for assessing restoration success. To address these questions, an approach combining analyses of in situ and ex situ soil functioning was used. The survey was conducted on recreated soil as compared to a control soil (i.e. soil before Gravel Extraction). Four topographic zones were sampled corresponding to 4 types of recreated soil functioning in terms of waterlogging conditions: Hemic Histosol without waterlogged periods, Hemic Histosol with temporary waterlogged periods, Hemic Histosol with the longest waterlogged periods and Interstratified Histosol without waterlogged periods. Soil respiration and SIR results showed that large stocks of organic matter are maintained after 3 years of restoration and proved able to sequester C in recreated soils. 3 years after restoration, nitrogen removal function measured through denitrification technique was restored in the Hemic Histosol with the longest waterlogged periods. These results demonstrate that waterlogging regime maintain the C stock and accelerate the restoration of denitrification process.
