scholarly journals Microfauna- and sedimentology-based facies analysis for palaeolandscape reconstruction in the back-barrier area of Norderney (NW Germany)

2021 ◽  
Vol 100 ◽  
Author(s):  
Annastasia Elschner ◽  
Juliane Scheder ◽  
Friederike Bungenstock ◽  
Alexander Bartholomä ◽  
Thorsten M Becker ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Tidal Flat ◽  
Sediment Cores ◽  
Depositional Environments ◽  
Coastal Protection ◽  
Protection Measures ◽  
Radiocarbon Dates ◽  
Minimum Age ◽  
Coastal Changes ◽  
The Impact

Abstract Palaeolandscape reconstructions at the German North Sea coast are essential for the understanding of coastal changes and dynamic landscape-forming processes. This study contributes to reconstructing Holocene coastal changes in the back-barrier area of the East Frisian island of Norderney and draws conclusions on the local palaeogeography. Five sediment cores were analysed in terms of sedimentology (grain-size distribution), geochemistry (TOC, TIC, N, C/N), microfauna (foraminifers and ostracods) and 13 radiocarbon dates. In order to identify driving environmental factors and support the facies interpretation, multivariate statistics (PCA) were carried out. Additional cores from the surrounding area (WASA Project and ‘Landesamt für Bergbau, Energie und Geologie’ (LBEG) Hannover) enabled correlation of the investigated cores over a transect of ~6 km, showing six depositional environments, which can be used for landscape reconstruction. Deposition starts with periglacial (aeolian and glaciofluvial) Pleistocene sediments, with subsequent pedogenesis followed by swamp conditions that develop into a salt marsh. The overlying tidal-flat sediments are partially cut by (fossil and recent) channel deposits. A hiatus at the base of the tidal-flat deposits that spans some 3000 years hints at their reworking caused by a combination of antrophogenic coastal protection measures and the impact of storms. Furthermore, based on the profile correlation and the age data, a widespread salt-marsh area with a minimum age of ~4000 cal BP is defined for the ‘Hohes Riff’ in the southwestern back-barrier of Norderney Island.

Depositional environments in the northern Barents Sea, from the last glacial to the present — preliminary results

2021 ◽  
Author(s):  
Vårin Trælvik Eilertsen ◽  
Rydningen Tom Arne ◽  
Matthias Forwick ◽  
Monica Winsborrow ◽  
Jan Sverre Laberg
Keyword(s):  
Sea Ice ◽  
Environmental Changes ◽  
Barents Sea ◽  
Ice Sheet ◽  
Depositional Environments ◽  
Radiocarbon Dates ◽  
Future Evolution ◽  
Last Glacial ◽  
Minimum Age ◽  
The Last Glacial

<p>The Eurasian Ice Sheet Complex was the world’s third largest ice mass during the last glacial maximum (LGM), and included the British, Fennoscandian and Svalbard–Barents Sea ice sheets. Of these three, the mostly marine-based Svalbard-Barents Sea Ice Sheet (SBIS) is the least well constrained in terms of ice sheet dynamics and deglacial retreat patterns. Improving the understanding of the behavior and decay of this marine paleo-ice sheet can provide knowledge that is relevant to understanding the future evolution of the marine terminating ice margins in Greenland and Antarctica, which are today undergoing rapid retreat and thinning.</p><p>We present high-resolution TOPAS sub-bottom profiler data and multi-proxy analyses of four sediment gravity cores (1.15 to 5.05 m long) retrieved from water depths of c. 250-550 m in a trough south of Kvitøya, NW Barents Sea. The data were collected during the Nansen Legacy (https:/arvenetternansen.com/) Paleo-cruise in 2018, with the aim of reconstructing the patterns and timing of deglaciation of the SBIS and postglacial environmental changes in the northern Barents Sea. The data show a succession of up to 10 m high and 400 m wide ridges, interpreted to be recessional push-moraines, representing small still-stands or re-advances of the ice front during its retreat in southwesterly direction. An up to 40 m high and 20 km long sedimentary wedge in the central and western part of the study area buries some of these moraines. This wedge is interpreted to be a grounding zone wedge representing a major still-stand or re-advance during the deglaciation.</p><p>The gravity cores are located distal to, on the distal slope and on top of the grounding zone wedge. A muddy diamict defines the lowermost unit in each core. It is interpreted to be primarily subglacial till. This till is covered by laminated mud, interpreted to represent sedimentation from meltwater plumes that emanated from the nearby ice margin. Massive marine mud containing scattered clasts (the clasts are interpreted to be ice rafted debris) define the uppermost unit in all cores. This is suggested to represent deposition from suspension settling and ice rafting in a glacier-distal environment at the end of the last glacial, as well as during modern conditions.</p><p>Radiocarbon dates (submitted for dating) will provide a minimum age for the formation of the grounding zone wedge and the recessional moraines in front of it. This will improve the chronology on the deglacial events forming these deposits and landforms. Together with detailed multi-proxy analyses of the sedimentary units, this will also provide new knowledge about the development from glacial conditions to a glacier-proximal and –distal, and an open marine environment from the last glacial to the present.</p>

scholarly journals IMPLICATIONS OF CORAL REEF MINING PITS ON 2D HYDRODYNAMICS

2020 ◽  
pp. 28
Author(s):  
Sebastiaan Klaver ◽  
Kees Nederhoff ◽  
Alessio Giardino
Keyword(s):  
Wave Energy ◽  
Reef Flat ◽  
Wave Interaction ◽  
Storm Surges ◽  
Small Island ◽  
Coastal Protection ◽  
Wave Runup ◽  
Protection Measures ◽  
Circulation Patterns ◽  
The Impact

Small Island Developing States (SIDS) are among the most vulnerable areas to the impact of natural hazards and climate change. Flooding due to storm surges and extreme waves, coastal erosion, and salinization of freshwater lenses are already a serious threat and could lead to irreversible consequences in the coming decades. On the other hand, reef flat mining is one of the most common practices to source the required material for the implementation of coastal protection measures on SIDS. There are strong concerns about this practice, because partial removal of the protective reef could increase wave impacts on the islands. However, the available data and knowledge on the effects of these mining pits are currently very limited. Klaver et al. (2019) studied the effects that pits may have on nearshore hydrodynamics and wave runup. Results obtained via numerical modeling indicate that excavation pits cause a decrease in infragravity wave energy around the fundamental mode of the reef, which is partly caused by reduced wave transmission. Similarly, changes in sea and swell (SS) wave energy are attributed to reduced transmission, as well as a decrease in wave dissipation and (triad) wave-wave interaction. Earlier studies by Ford et al. (2013) and Yao et al. (2016) point out that mining pits may lead to additional two-dimensional effects. In this presentation, we present the potential 2D effects of reef flat excavation pits on nearshore hydrodynamics. More specifically, we aim to assess the impact of excavation pits on nearshore circulation patterns, which could be an indicator of coastal morphological changes.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/85-IMM66eWE

scholarly journals Impact of coastal forcing and groundwater recharge on the growth of fresh groundwater resources in a mega-scale beach nourishment

2017 ◽  
Author(s):  
Sebastian Huizer ◽  
Max Radermacher ◽  
Sierd de Vries ◽  
Gualbert H. P. Oude Essink ◽  
Marc F. P. Bierkens
Keyword(s):  
Groundwater Recharge ◽  
Land Surface ◽  
Morphological Changes ◽  
Groundwater Resources ◽  
Beach Nourishment ◽  
Coastal Protection ◽  
Tidal Dynamics ◽  
Fresh Groundwater ◽  
Protection Measures ◽  
The Impact

Abstract. Large concentrated sand replenishments or nourishments are one of the few coastal protection measures that can simultaneously result in an increase of local fresh groundwater resources. For a large beach nourishment called the Sand Engine – constructed in 2011 at the Dutch coast – we have examined the impact of groundwater recharge and coastal forcing (i.e. natural processes that drive coastal hydro- and morphodynamics) on the growth of the fresh groundwater resources between 2011 and 2016. Measurements of the morphological change and the tidal dynamics were incorporated in a calibrated three-dimensional and variable-density groundwater model of the study area. Simulations with this model showed that the detailed incorporation of the local hydro- and morphodynamics and the actual recharge rate can result in a reliable reconstruction of the growth in fresh groundwater resources. Similarly, the neglect of tidal dynamics, land-surface inundations and morphological changes in model simulations can result in considerable overestimations of the volume of fresh groundwater. In particular wave run-up and coinciding coastal erosion during storm surges limit the growth in fresh groundwater resources in dynamic coastal environments, and should be considered at potential nourishment sites to delineate the area that is vulnerable to salinization.

Variability in the erosion response of vertical sections of salt marsh sediments exposed to tidal flat conditions

2021 ◽  
Author(s):  
Olivia Shears ◽  
Iris Möller ◽  
Tom Spencer ◽  
Ben Evans ◽  
Kate Royse
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Tidal Flat ◽  
Organic Matter Content ◽  
Matter Content ◽  
Coastal Protection ◽  
Sediment Type ◽  
Sediment Removal ◽  
Substrate Properties ◽  
Vertical Sections

<p>Salt marsh ecosystems are important for supporting biodiversity, sequestering carbon and providing natural coastal protection. Evidence for their existing and potential future loss through marginal erosion is therefore of concern. However, the factors governing spatial variability in the rates of erosion at salt marsh margins – including between creek banks within individual salt marsh sites – remain relatively poorly understood. Accurate prediction of changes to the marsh edge, and thus marsh areal extent, requires more complete understanding of the dynamics and mechanisms occurring at exposed marsh fronts.</p><p>In this study, we present observations of the responses of vertical sections of marsh substrate exposed to tidal flat conditions, during a field experiment over a six-month period. Vertical sections were extracted from natural and restored sites at two salt marshes in the UK: Northey Island, eastern England, where sediment is fine-grained, and Hesketh Out Marsh West, north-west England, where sediment is typically sand/silt-dominated. The study specifically investigates the role of different sedimentology and downcore substrate properties, including lamination and rooting structures, on observed change in the exposed vertical sections. Images captured in the field are analysed using structure-from-motion photogrammetry and used to create 3-D models of surface change. This is coupled with laboratory testing of downcore sedimentary characteristics, such as particle size distribution and organic matter content.</p><p>The study finds that within-core and between-core variability in substrate response to erosive forcing appears to be partly related to variability in sedimentology. Sediment from sand-dominated layers, such as those found in the cores extracted from Hesketh Out Marsh West, was more rapidly and consistently (i.e. across the sediment cores) removed than clay-silt rich sediment. This grain-scale sediment removal resulted in specific morphological responses, whereby ‘chunks’ of substrate were lost, creating cavity areas further exposed to hydrodynamic forcing. Intrinsic biophysical characteristics, including sediment type and the presence of vegetation structures, can impact vertical connectivity within salt marsh substrates. Observations of structural change in the vertical sections over the six-month study period suggest that reduced downcore connectivity in restored salt marsh substrates results in increased desiccation, cracking and bulk sediment removal. An improved understanding of how such intrinsic substrate properties impact marsh front dynamics will facilitate more accurate predictions of marsh evolution and potential ecosystem service provision under future conditions.</p>

Investigating Burnt Mounds in Clydesdale during Motorway Construction

1998 ◽  
Vol 21 (1) ◽  
pp. 1-28
Author(s):  
John A Atkinson ◽  
Camilla Dickson ◽  
Jane Downes ◽  
Paul Robins ◽  
David Sanderson
Keyword(s):  
Bronze Age ◽  
Research Strategy ◽  
Archaeological Evidence ◽  
Radiocarbon Dates ◽  
Short Account ◽  
And Function ◽  
The Impact ◽  
The Bronze Age

Summary Two small burnt mounds were excavated as part of the programme to mitigate the impact of motorway construction in the Crawford area. The excavations followed a research strategy designed to address questions of date and function. This paper surveys the various competing theories about burnt mounds and how the archaeological evidence was evaluated against those theories. Both sites produced radiocarbon dates from the Bronze Age and evidence to suggest that they were cooking places. In addition, a short account is presented of two further burnt mounds discovered during the construction of the motorway in Annandale.

Do regulations protect workers from occupational exposures to carcinogenic, mutagenic and reprotoxic (CMR) agents in France?

2017 ◽  
Vol 75 (5) ◽  
pp. 389-397
Author(s):  
Nathalie Havet ◽  
Alexis Penot ◽  
Morgane Plantier ◽  
Barbara Charbotel ◽  
Magali Morelle ◽  
...  
Keyword(s):  
Occupational Exposure ◽  
Occupational Exposures ◽  
International Agency ◽  
The European Union ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Protection Measures ◽  
Limit Value ◽  
Logistic Regressions ◽  
The Impact

ObjectiveThis article explores the impact of regulations on the implementation of collective protections in France to occupational exposure to carcinogenic, mutagenic and reprotoxic (CMR) agents.MethodsIndividual data from the French national cross-sectional survey of occupational hazards conducted in 2010 were analysed. We investigated whether stricter regulations and longer exposures were associated with higher level of collective protection using multivariate logistic regressions.ResultsGeneral ventilation, for which effect is limited as collective protection for CMR products, was present in 19% of situations involving CMR agents while isolation chambers, the most effective form of protection, were only very rarely implemented. Multilevel logistic regressions show that exposure situations to products classified as category 1 or 2 by the European Union do not have a higher probability of benefiting from a collective protection measures. Exposures to products with a Binding Occupational Exposure Limit Value selectively benefited from a better level of protection. Exposures to agents entered on the International Agency for Research on Cancer (IARC) list of proven or probable carcinogens benefited more from effective collective protections than products suspected to be carcinogens but not yet classified by IARC.ConclusionsThese results suggest that the dissemination of evaluations of carcinogens by the IARC translate into improved protective measures even though the IARC classification has no mandatory impact on regulations.

Impact of extreme hydrological perturbation on sediment distribution from source to sink, PETM, Spain.

2021 ◽  
Author(s):  
Marine Prieur ◽  
Alexander C. Whittaker ◽  
Fritz Schlunegger ◽  
Tor O. Sømme ◽  
Jean Braun ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Adaptation ◽  
Global Climate ◽  
Depositional Environments ◽  
Lead Author ◽  
Current Increase ◽  
Sediment Distribution ◽  
Current Climate ◽  
Source To Sink ◽  
The Impact

<p>Sedimentary dynamics and fluxes are influenced by both autogenic and allogenic forcings. A better understanding of the evolution of sedimentary systems through time and space requires us to decipher, and therefore to characterise, the impact of each of these on the Earth’s landscape. Given the current increase in the concentration of atmospheric carbon, studying the impact of rapid and global climate changes is of particular importance at the present time. Such events have been clearly defined in the geologic record. Among them, the Paleocene-Eocene Thermal Maximum (PETM) has been extensively studied worldwide and represents a possible analogue of the rapid current climate warming.</p><p>The present project focuses on the Southern Pyrenees (Spain) where excellent exposures of the Paleocene-Eocene interval span a large range of depositional environments from continental to deep-marine. These conditions allow us to collect data along the whole depositional system in order to document changes in sediment fluxes and paleohydraulic conditions. Because hydrological conditions have an impact on sediment transport through hydrodynamics, paleoflow reconstructions can shed light on changes in sediment dynamics. This information is reconstructed from the statistical distributions of channel morphologies, characteristic system dimensions including bankfull channel depth and width, and grain-sizes.</p><p>With this approach, our aim is to provide both qualitative and quantitative assessments of the magnitude and extent of the perturbation of sedimentary fluxes along an entire source-to-sink system during an episode of extreme climate change. This will lead to a better understanding of the impact of abrupt climate change on earth surface systems in mid-latitudinal areas, with possible implications for current climate adaptation policy.</p><p>This research is carried out in the scope of the lead author’s PhD project and is part of the S2S-FUTURE European Marie Skłodowska-Curie ITN (Grant Agreement No 860383).</p>

scholarly journals EVALUATION AND DEVELOPMENT OF COASTAL PROTECTION MEASURES FOR SMALL ISLANDS IN THE WADDEN SEA

2014 ◽  
Vol 1 (34) ◽  
pp. 5 ◽  
Author(s):  
Theide Wöffler ◽  
Holger Schüttrumpf ◽  
Roger Häußling ◽  
Hilmar Von Eynatten ◽  
Arne Arns ◽  
...  
Keyword(s):  
Wadden Sea ◽  
Coastal Protection ◽  
Small Islands ◽  
Protection Measures

scholarly journals Understanding epistemic uncertainty in large-scale coastal flood risk assessment for present and future climates

2018 ◽  
Author(s):  
Michalis I. Vousdoukas ◽  
Dimitrios Bouziotas ◽  
Alessio Giardino ◽  
Laurens M. Bouwer ◽  
Evangelos Voukouvalas ◽  
...  
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Flood Risk ◽  
Large Scale ◽  
Epistemic Uncertainty ◽  
Coastal Protection ◽  
Flood Risk Assessment ◽  
Coastal Flood ◽  
Coastal Flood Risk ◽  
The Impact

Abstract. An upscaling of flood risk assessment frameworks beyond regional and national scales has taken place during recent years, with a number of large-scale models emerging as tools for hotspot identification, support for international policy-making and harmonization of climate change adaptation strategies. There is, however, limited insight on the scaling effects and structural limitations of flood risk models and, therefore, the underlying uncertainty. In light of this, we examine key sources of epistemic uncertainty in the Coastal Flood Risk (CFR) modelling chain: (i) the inclusion and interaction of different hydraulic components leading to extreme sea-level (ESL); (ii) inundation modelling; (iii) the underlying uncertainty in the Digital Elevation Model (DEM); (iv) flood defence information; (v) the assumptions behind the use of depth-damage functions that express vulnerability; and (vi) different climate change projections. The impact of these uncertainties to estimated Expected Annual Damage (EAD) for present and future climates is evaluated in a dual case study in Faro, Portugal and in the Iberian Peninsula. The ranking of the uncertainty factors varies among the different case studies, baseline CFR estimates, as well as their absolute/relative changes. We find that uncertainty from ESL contributions, and in particular the way waves are treated, can be higher than the uncertainty of the two greenhouse gas emission projections and six climate models that are used. Of comparable importance is the quality of information on coastal protection levels and DEM information. In the absence of large-extent datasets with sufficient resolution and accuracy the latter two factors are the main bottlenecks in terms of large-scale CFR assessment quality.

scholarly journals GUIDELINES FOR DESIGNING SAND NOURISHMENT ON LOW TO VERY EXPOSED COASTS

2020 ◽  
pp. 5
Author(s):  
Henrik Vinge Karlsson ◽  
Britt Gadesboll Larsen ◽  
Per Sorensen
Keyword(s):  
Natural Variation ◽  
Primary Objective ◽  
Coastal Protection ◽  
Special Focus ◽  
Protection Scheme ◽  
Coastal Cliff ◽  
Sand Nourishment ◽  
The Impact ◽  
Privately Owned ◽  
Insight Into

Danish law establishes a common right of passage on foot along the Danish shoreline, even though beaches are often privately owned. The law also states that coastal protection must not hinder this. Therefore, sand nourishment should be part of every coastal protection scheme against erosion. Sand nourishments can be designed in numerous ways depending on their objectives. As part of the European Interreg project, Building With Nature (BWN), guidelines will be developed by the Danish Coastal Authority (DCA) in end-2020. This abstract presents these guidelines with special focus on the coasts of Denmark. Special emphasis will be on insight into the natural variation of the coasts, as this is vital both when designing effective coastal protection schemes and when evaluating the impact of the nourishment. In this project, the pathway along which sediment is being transported spans from offshore at the outer bar to the coastal cliff. The aim is to be able to determine the along- and cross-shore paths, along which the nourishment sand is transported, the diffusion velocity of the nourishment and the impact on the surrounding coasts. Based on the results of the multiple analysis, the primary objective is to produce guidelines on how to use sand nourishment to counteract erosion in a sustainable and socioeconomic way.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/nIrFFmH98V8

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