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The data presented here were collected onboard the NIOZ RV - Pelagia in June and October 2017. Bathymetric (multibeam), sediment and benthos samples were collected along an asymmetrical sand wave field 20 km to the west of island Texel., The data presented here were collected onboard the NIOZ RV - Pelagia in June and October 2017. Bathymetric (multibeam), sediment and benthos samples were collected along an asymmetrical sand wave field 20 km to the west of island Texel.

Both physical and electrical impacts have been linked to North Sea fisheries activity. This study evaluates how these effects can influence marine ecological functioning by assessing their consequences on benthic pelagic coupling. Experiments were conducted on sediment microcosms taken from 9 North Sea and 2 Eastern Scheldt locations. Samples were subjected to physical disturbances by mechanically stirring the sediment surface or electrical stimulation with exposure to high frequency pulsed bipolar or direct currents. Electrical exposure times of 3 and 120-s were used to simulate in situ exposure times related to sole (Solea solea) and razor clam (Ensis spp.) electric fisheries respectively. Water column oxygen rapidly declined after sediment resuspension, inducing an immediate uptake ranging from 0.55 to 22 mmol oxygen per m−2 of sediment disturbed. Mechanical disturbances released the equivalent of up to 94 and 101 h of natural ammonium and silicate effluxes respectively. Fresh organic material significantly predicted the magnitude of mechanical-induced oxygen, ammonium, phosphate and silicate changes. No biogeochemical effects from bipolar (3 s or 120 s) or 3-s direct current exposures were detected. However, significant changes were induced by 120-s exposures to direct currents due to electrolysis and ionic drift. This lowered the water column pH by 1–1.3 units and caused the appearance of iron oxides on the sediment surface, resulting in the equivalent of 25–28 h of sedimentary phosphate removal. Our findings demonstrate that prolonged (+1 min) exposure to high frequency pulsed direct currents can cause electrochemical effects in the marine environment, with implications for phosphorus cycling. Nevertheless, bi-directional pulsed currents used in flatfish pulse trawling and AC waveforms featured in Ensis electrofishing, seem to severely limit these effects. Mechanical disturbance, on the other hand, causes a much greater effect on benthic pelagic coupling, the

Sand waves are dynamic and regular bedforms that are ubiquitous in sandy shelf seas. However, information about the ecological characteristics (e.g., benthic community structure) and their spatial variability within these habitats is very limited. To address this knowledge gap, we undertook a field campaign in summer 2017 to investigate the macrofaunal community composition of a sand wave area off Texel (Dutch part of the North Sea). Sand waves in this area were asymmetrical, with longer gentle slopes that were approximately double in length to the shorter steep slopes. The benthic distribution along the different parts of these sand waves was assessed by collecting a large number of box cores within a transect line (~1 km). We show considerable variability in the individual, biomass and taxon densities, which were all significantly higher on the steeper slopes of the sand waves. These results are consistent with the trends observed in both the abiotic parameters and video analysis that were measured in two recent studies at the same study area. Our results provide valuable insight into the small-scale patterns of variability in asymmetrical dynamic bedform environments, where gentle slopes seem to be primarily controlled by physical forces, while steep slopes are more under biotic control.

22 stations on and around the Brown Bank were selected to study local ecological variation and to link ecological with geomorphological data. Macrobenthos was collected with a box corer and identified to the lowest possible taxonomic level, in three replicates per station. Sediment characteristics (grain size, TOC, chlorophyll α etc.) were measured for each replicate. Geomorphological data (bathymetry, backscatter, BPI etc.) were derived from multibeam echosounding at each station.

High-resolution surveying techniques of subtidal soft-bottom seafloor habitats show higher small-scale variation in topography and sediment type than previously thought, but the ecological relevance of this variation remains unclear. In addition, high-resolution surveys of benthic fauna show a large spatial variability in community composition, but this has yet poorly been linked to seafloor morphology and sediment composition. For instance, on soft-bottom coastal shelves, hydrodynamic forces from winds and tidal currents can cause nested multiscale morphological features ranging from metre-scale (mega)ripples, to sand waves and kilometre-scale linear sandbanks. This multiscale habitat heterogeneity is generally disregarded in the ecological assessments of benthic habitats. We therefore developed and tested a novel multiscale assessment toolbox that combines standard bathymetry, multibeam backscatter classification, video surveying of epibenthos and box core samples of sediment and macrobenthos. In a study on the Brown Bank, a sandbank in the southern North Sea, we found that these methods are greatly complementary and allow for more detail in the interpretation of benthic surveys. Acoustic and video data characterised the seafloor surface and subsurface, and macrobenthos communities were found to be structured by both sandbank and sand wave topography. We found indications that acoustic techniques can be used to determine the location of epibenthic reefs. The multiscale assessment toolbox furthermore allows formulating recommendations for conservation management related to the impact of sea floor disturbances through dredging and trawling., Aircraft Noise and Climate Effects, Hydraulic Engineering, Environmental Fluid Mechanics

High-resolution surveying techniques of subtidal soft-bottom seafloor habitats show higher small-scale variation in topography and sediment type than previously thought, but the ecological relevance of this variation remains unclear. In addition, high-resolution surveys of benthic fauna show a large spatial variability in community composition, but this has yet poorly been linked to seafloor morphology and sediment composition. For instance, on soft-bottom coastal shelves, hydrodynamic forces from winds and tidal currents can cause nested multiscale morphological features ranging from metre-scale (mega)ripples, to sand waves and kilometre-scale linear sandbanks. This multiscale habitat heterogeneity is generally disregarded in the ecological assessments of benthic habitats. We therefore developed and tested a novel multiscale assessment toolbox that combines standard bathymetry, multibeam backscatter classification, video surveying of epibenthos and box core samples of sediment and macrobenthos. In a study on the Brown Bank, a sandbank in the southern North Sea, we found that these methods are greatly complementary and allow for more detail in the interpretation of benthic surveys. Acoustic and video data characterised the seafloor surface and subsurface, and macrobenthos communities were found to be structured by both sandbank and sand wave topography. We found indications that acoustic techniques can be used to determine the location of epibenthic reefs. The multiscale assessment toolbox furthermore allows formulating recommendations for conservation management related to the impact of sea floor disturbances through dredging and trawling.

High resolution maps of sandy seafloors are valuable to understand seafloor dynamics, plan engineering projects, and create detailed benthic habitat maps. This paper presents multibeam echosounder backscatter classification results of the Brown Bank area of the North Sea. We apply the Bayesian classification method in a megaripple and sand wave area with significant slopes. Prior to the classification, corrections are implemented to account for the slopes. This includes corrections on the backscatter value and its corresponding incident angle. A trade-off in classification resolutions is found. A higher geo-acoustic resolution is obtained at the price of losing spatial resolution, however, the Bayesian classification method remains robust with respect to these trade-off decisions. The classification results are compared to grab sample particle size analysis and classified video footage. In non-distinctive sedimentary environments, the acoustic classes are not attributed to only the mean grain size of the grab samples but to the full spectrum of the grain sizes. Finally, we show the Bayesian classification results can be used to characterize the sedimentary composition of megaripples. Coarser sediments were found in the troughs and on the crests, finer sediments on the stoss slopes and a mixture of sediments on the lee slopes., Aircraft Noise and Climate Effects

This thesis explores the links between sexuality and academic achievement for girls in secondary education. It investigates primarily how sexual and learner identities are embodied by young women and the implications of this for their educational success or failure, their emotional well-being, their relationships and their imagined adulthoods. I research a range of young women's experiences across the spectrum of educational attainment and draw from a range of self-identified and emergent sexualities and asexual practices. In contrast to much work which explores only the experience of young women's developing heterosexualities, the research presented here focuses particularly on young women who have emergent lesbian, bisexual or trans-gendered identities or who practise culturally marginalised forms of heterosexuality. Although based on a small selection of case studies, it includes the experience of asylum seekers pupils, Traveller pupils and minority ethnic pupils. I argue here that the Cartesian mind/body split as it is enshrined in the standards and school effectiveness agendas has detrimental consequences for both highly achieving pupils and those who are not academically successful as defined within these agendas. The study concludes by suggesting that learning about sexuality and sexual knowledge needs to be more centrally and openly present in schools in order that marginalised sexual identities are able to participate more fully in learning that the complexity of the relationship between sexuality and learning in psychoanalytic accounts is made available to teachers and that more research is undertaken to make visible girls who 'do girl' differently, by adopting non-normative sexualities or through the practice of masculinity.

This thesis explores the links between sexuality and academic achievement for girls in secondary education. It investigates primarily how sexual and learner identities are embodied by young women and the implications of this for their educational success or failure, their emotional well-being, their relationships and their imagined adulthoods. I research a range of young women's experiences across the spectrum of educational attainment and draw from a range of self-identified and emergent sexualities and asexual practices. In contrast to much work which explores only the experience of young women's developing heterosexualities, the research presented here focuses particularly on young women who have emergent lesbian, bisexual or trans-gendered identities or who practise culturally marginalised forms of heterosexuality. Although based on a small selection of case studies, it includes the experience of asylum seekers pupils, Traveller pupils and minority ethnic pupils. I argue here that the Cartesian mind/body split as it is enshrined in the standards and school effectiveness agendas has detrimental consequences for both highly achieving pupils and those who are not academically successful as defined within these agendas. The study concludes by suggesting that learning about sexuality and sexual knowledge needs to be more centrally and openly present in schools in order that marginalised sexual identities are able to participate more fully in learning that the complexity of the relationship between sexuality and learning in psychoanalytic accounts is made available to teachers and that more research is undertaken to make visible girls who 'do girl' differently, by adopting non-normative sexualities or through the practice of masculinity.