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Delta systems are not only the interface between the land and the ocean, but also sites of long-term sediment accumulation, pollen and organic matter storage that can be used for environmental investigations. Deltas are particularly sensitive to climate and sea level change, which can be expressed with change in the shelf morphology and the associated vegetation. The Niger Delta, ideally located in a region of great sensitivity to climate change and sea level fluctuations, offers the possibility to provide an insight on the “late” Quaternary history of environmental change in West Equatorial Africa. Up to now, this deltaic system has been sparsely studied, compared with other major tropical deltas and therefore, its response to past climate change and sea level fluctuation is poorly understood. This study aims to fill this scientific gap through a detailed analysis of a multi-proxy dataset collected from three gravity cores obtained from the shallow margin of the Niger Delta. The dataset included sedimentology, grain size, geochemistry, calcareous nannoplankton, foraminifera and palynomorphs. Using these data, a robust biostratigraphic framework was established for the littoral shallow offshore deltaic sequence. In addition, a refined biostratigraphic technique was developed based on foraminiferal and nannofossil (NN) indicators linked to the Marine Isotopes Stages, which helped to define the age model of the sequences (NN19= MIS2, NN20 & NN21=MIS1). Within this new biostratigraphic framework the spatial and temporal evolution of the coastal environment of the Niger Delta were evaluated. This study hypothesised that the dynamics of the Intertropical Convergence Zone (ITCZ), the West African Monsoon (WAM) and sea level fluctuation played a major role in shaping the landscape in the Niger Basin and adjacent coastal regions. The palynological sequences defined in the three gravity cores show very similar fluctuations, with a dominance of the Afromontane Forest (Podocarpaceae), Freshwater Swamp (Cyperaceae), Savannah (Poaceae) and Lowland Rainforest (Polypodiaceae) during the late glacial and deglaciation period, followed by the iv development of the Mangrove (Rhizophoraceae) during the Early to mid-Holocene. In addition, high values of charred grass cuticles and Ti/Zr are observed during the late glacial, whereas high values of Fe/S ratio and planktonic foraminiferal are concomitant to the expansion of mangrove vegetation during the interglacial period. These records suggest dry conditions, with lower sea level during the late glacial and deglaciation periods, and warm conditions leading to the rise of the sea level during the interglacial in the Early to mid-Holocene periods respectively. To summarise, the outcome of this study indicates that the records link well in time to the known hypotheses of the land-ocean interactions providing the main drivers for study of the climate and sea level change in relation to the sedimentary and vegetation evolution of the Niger Delta compared with previous studies from West Equatorial Africa. The results permit a re-evaluation of the controls of climate, sea level and sediment supply contributing to the understanding of the two stages in palaeovegetation and the littoral/coastal evolution of the Niger Delta (progradation and retrogradation) for the future exploration, exploitation and sustainability of the region.

This thesis introduces new relative sea level datasets from the Forth and Tay Estuaries dating between 1900 and 2010 and uses these to analyse sea level oscillations, surge components and to influence future sea level projections. Prior to this research, relative sea levels had not been analysed across this region. These datasets were collated and corrected using renowned methods and investigated using Shennan et al.’s (2012) GIA corrections, Torrence and Compo’s (1998) Morlet wavelet transform and Graff’s (1981) sea level maxima analysis. The relative sea level data were then used to support adaptations of two sea level projection models to 2100; the UK Climate Projections 2009 (UKCP09) probabilistic model and Vermeer and Rahmstorf’s (2009) temperature-sea level relationship projections model. These models were, in turn, used to project the impact of extreme relative sea levels on local infrastructure by 2100. This research revealed that relative sea level in the Forth and Tay Estuaries between 1900 and 2010 rose at a rate of 0.27 to 0.56 mm a-1, which is smaller than the global average of 1.7 mm a-1 (Church and White, 2011). Tidal residuals were commonly observed to be approximately 0.4 and 0.7 m at Leith and Dundee between 2003 and 2010, whilst the highest sea level maxima across 5 ports in the region ranged between 3.27 and 4.13 m above OD. Adaptions of the UKCP09 model reduced the original projections for 2100 of between 31.3 and 35.1 cm to between 24.3 and 27.5 cm above the 1990 mean. Similarly, adaptions of the Vermeer and Rahmstorf (2009) model reduced projections from 107.5 cm to between 50.9 and 54.2 cm above the 1990 mean. These adapted projections, when added to the extreme 2100 sea level calculations, suggests that the highest extreme sea level by 2100 could reach the present day quayside heights at selected locations in the Forth and Tay Estuaries. The approach and results are replicable across other regions, thereby refining projections made by previous authors.

Les hautes latitudes font parties des régions du monde les plus sensibles au réchauffement climatique contemporain. Depuis la fin du Petit Age Glaciaire, les paysages du Svalbard enregistrent une période de transition paraglaciaire, engendrée par une augmentation des températures et des précipitations et la fonte généralisée des glaciers. Il existe peu de travaux scientifiques concernant l’impact potentiel des changements globaux sur les littoraux des régions froides, bien que ceux-ci représentent 30% des littoraux mondiaux. Ainsi, 1% des littoraux arctiques ont été étudiés suffisamment en détail pour permettre une description quantitative des processus en action. Dans le cadre de cette thèse, nous cherchons à comprendre de quelles façons les littoraux polaires enregistrent les changements climatiques contemporains. Sur la presqu’île de Brøgger, au Spitsberg nord-occidental, plusieurs systèmes côtiers ont été étudiés par le biais de différentes méthodologies adaptées: une côte basse meuble et plusieurs sites de falaises, de lithologies et d’expositions différentes. La fonte des glaciers et les modifications engendrées dans l’organisation du réseau hydrographique ont permis la progradation rapide de la portion de côte basse meuble depuis la fin du PAG. Depuis 1990, cette tendance s’inverse avec une prédominance à l’érosion côtière, annonçant la fin de la transition paraglaciaire pour ce système. Concernant les falaises, les actions marines, quels que soient les lithologies, ont une influence notable sur leur évolution. Néanmoins, les processus continentaux des domaines périglaciaires et paraglaciaires sont prédominants dans leur évolution. / Arctic areas are the most sensitive to global warming. Since the end of the LIA, Svalbard’s landscape has been in a period of paraglacial transition, caused by an increase in temperatures and precipitation and the melting of glaciers. Little is known about the potential impact of global changes on the coasts of cold regions, although these represent 30% of the world's coastlines. Indeed, only 1% of the Arctic coastlines have been studied in sufficient detail to allow a quantitative description of the processes in action. As part of this thesis, we seek to understand the ways in which polar coasts record contemporary climate change. On the Brøgger peninsula, northwest Spitsbergen, several coastal systems have been studied through different adapted methodologies: a low-lying coast and several sites of cliffs, with lithology and different exposures. The melting of glaciers and the changes in the organization of the hydrographic network have allowed the rapid progradation of the low-lying coast since the end of the PAG. Since 1990, this trend has reversed with a predominance of coastal erosion, announcing the end of the paraglacial transition for this system. Regarding the cliffs, our results show that marine actions, whatever the lithology, have a significant influence on their evolution. Nevertheless, paraglacial and periglacial continental processes remain predominant in their evolution.

This thesis presents new late Holocene relative sea-level reconstructions in the Humber Estuary, and examines the relationship between sea-level change and the salinisation of the groundwater resource. Relative sea-level reconstructions were produced using lithological and biostratigraphical analyses from two sites. Single and multi-proxy transfer functions were developed using diatom and foraminifera training sets from three sites in the Humber Estuary, with the multi-proxy transfer function providing the best performance. However, the application of the transfer functions was limited by the availability of modern analogues and generally poor preservation of microfossils. Eight new sea-level index points were produced, providing constraints of relative sea-level change between 4022-1470 cal years BP. The reconstructions were consistent with existing data, offering new constraints for the previously identified expansion and contraction of estuarine conditions during the late Holocene. In the outer estuary, two sea-level index points provided a record for an expansion between 3395-3227 cal years BP not previously constrained by sea-level index points. In the inner estuary, the sea-level index points indicated an expansion of estuarine conditions at 4022 cal years BP. Two of the points now provide the youngest constraints for the inner estuary. Multiple sea level and groundwater abstraction scenarios for time periods in the past and future were undertaken using a numerical model. These determined the contribution of sea level and abstraction to changes in the groundwater and saline intrusion; sea-level rise increased saline waters within the aquifer, and abstraction induced additional saline intrusion. Future sea-level rise will also result in an increase in aquifer salinity. A lack of data and consensus over the current conditions of the aquifer and groundwater was identified, with significant further research across multiple disciplines required for sustainable management and use of the groundwater resource.

Extreme sea levels exert a major control over the coastal zone, and many studies have found that they are changing at locations around the world. This thesis tests the assertion that these changes are predominantly caused by the global rise in mean sea level by investigating the importance of variability, over a range of timescales, in the other main components of sea level. The analysis is undertaken using a quasi-global dataset of 220 tide gauge records that range in length from 28-164 years. For the first objective, secular (linear) trends in 15 different tidal levels were found to be significant (95% confidence) at between 34% and 63% of the study sites, depending on the tidal level analysed. Significant trends were distributed at sites around the world and at 37 sites the magnitude of the trends was over 1 mm/yr, comparable to the rise in global mean sea level over the 20th century. Spatial patterns were observed on local, regional and global scales. The global rise in mean sea level may be the cause of significantly more positive trends than negative trends occurring in high water levels, but other mechanisms appear more important at many locations. The second objective assessed changes in the meteorological component of sea level. Significant tide-surge interaction was found at 59% or 81% of the 220 study sites, depending on the method used. At locations that have significant tide-surge interaction skew surge is the better parameter for the representation of the meteorological component. Only 13% of sites had significant secular trends in skew surge. There were significantly fewer negative trends in skew surge than the non-tidal residual, which may be because the influence of phase offsets is removed when using skew surge. Inter-annual variability in skew surge is large, but strong correlations between different regional skew surge and climate indices were not found to be significant in this thesis. The third objective evaluated how the variability in the tidal and meteorological components of sea level - together with changes in mean sea level - influenced seasonal, inter-annual and secular changes in extreme sea levels. Variability in baseline extreme sea level (i.e. timescales greater than 6 months) was dominated by secular changes in mean sea level and the seasonal and inter-annual variability in mean sea level and skew surge, at most sites. The combined magnitude of the extracted signals reached 2.4 m in the North Sea, but was typically between 0.8 and 1.2 m. Changes in the relative phase of each signal, as well as the magnitude, may alter the magnitude of extreme sea levels. If independent signals in different components and timescales occurred in phase then the baseline extreme sea levels would increase at all sites in this study. This thesis presents novel findings that show that while secular trends in mean sea level are important to changes in extreme sea levels, significant changes are occurring in all components and over many timescales. Shifts in both the magnitude and phase of signals in all components and over all timescales should be considered in extreme sea level projections. Accurate calculation of extreme sea levels has important implications for applications in the coastal zone, including flood defence, navigation, energy extraction and habitat protection.

Rapid increases in coastal developments in the Sultanate of Oman recently, including large ports with industries, crude oil refineries, mining and industrial activities, have often produced point sources of metal and organic contaminations in the local marine systems. Although advances have been made in measuring and understanding the trace metal speciation in aquatic system using a dynamic technique DGT (Diffusive Gradients in Thin-films) or using other equilibrium techniques, measuring metal speciation in situ in seawater that polluted by crude oil is still extremely challenging. Without the technology and the information, it is difficult to assess the effects of oil ligands on metal speciation associated with the oil refineries and industries. In the present study, the DGT technique has been developed further for measuring metal speciation in seawaters in the presence of oil. The influence of oil ligands on the speciation of trace metals (Cd, Co, Cu, Ni, Pb and Zn) has been investigated in synthetic solutions of 0.5 and 0.7 mol/L NaCl containing different level of Oman crude oil. DGT of different types in diffusive layers (pore size and thicknesses), binding layers (Chelex resin and Fe oxide) and different types of membranes (dialysis membranes (1000 MWCO and 3500 MWCO) and 0.05 mm thickness Nafion112 membrane) were used. The diffusion coefficients were determined for each metal, using a diffusion cell, through filter membrane and diffusive gel with and without dialysis and Nafion112 membranes. The measured diffusion coefficients of all metals in diffusive gel plus dialysis membrane were significantly lower than gel alone. When Nafion112 membrane wasused with the diffusive gel, the diffusion coefficients of all metals were much lower,up to 80 times lower for Cu, Cd and Ni. The potential of using DGT for determining labile metals species in seawater in the presence of crude oil was evaluated in mixed solution of NaCl and oil with varying mixing periods (0.25 day, 0.5 day, 1 day, 2 days, 4 days and 6 days) and oil concentrations (1, 3, 5, 7, 25 OWR% (oil water ratio), w/v). It was demonstrated that organic ligands from crude oil influenced the lability of trace metals. The combination of five types of DGT devices (OP-DGT, RG-DGT, (dialysis 1000Da)-DG, (dialysis 3500Da)-DGT, (Nafion 112)-DGT) were used for speciation of metals at 1 and 4 oil water ratio (OWR%), and 48 h mixing time. Lower concentrations of labile metals were determined with the higher level of oil in the synthetic solution when using Nafion 112-DGT, due to the exclusion of large colloids and negatively charged metal complexes by Nafion 112 membrane. No significance differences were observed between OP-DGT and RG-DGT for Co, Ni, Zn and Pb at 1% OWR and Co, Ni and Pb in at 4% OWR. This suggests the labile complexes of metals and organic ligands from oil may be smaller than the pore size of the restricted diffusive gel. Comparing (Dialysis 1000MWCO)-DGT and 1000MWCO- Micro Float microdialysis measurements indicated that Co, Cd, Cu and Zn were complexed with ligands small enough to pass through the 1000 MWCO- Micro Float microdialysis but not labile enough to be retained in the (Dialysis 1000 MWCO)-DGT samplers. DGT technique was applied to soils contaminated with both metals and crude oil to evaluate the effect of oil level and aging on the availability of metals in soils. The dissolved metals in soil solution (Csoln), labile concentrations by DGT (CDGT) and extractable concentration by CaCl2 were measured. Values of labile pool size, Kd, and R (ratio of CDGT and Csoln) were calculated and the kinetic parameters (response time Tc and desorption rate k−1) were obtained using DIFS (DGT Induced Fluxes in Soils and sediments) model. Increases of crude oil treatments in soils promoted the formation of non-labile species of Cu and Pb and limited the availability of both metals. The time scales of the kinetic exchanges obtained from DGT measurements and DIFS modelling was reflected by the range of determined Tc values: from seconds to 3 hours. The gradual decrease of Kd values for Cu with time in three studied soils with and without oil application may be attributed to the strong tendency of Cu to be associated with the solid phase with increasing incubation time. The Kd values of Ni were generally decreased with adding of crude oil amendments in three soils may be due to the release of Ni species from solid phase and crude oil to soil solution. Three soils were resupply of Cd and Pb in general very slow to measure. The generally slower release rates of Cd and Pb compared to other studied metals may reflect the lower concentration of Cd and Pb which allowed a higher proportion of them to associate strongly with organic ligands sites with slower release rates. The trend changes for k-1 values of studied metals in three selected soils were influenced by crude oil amendments and aging time. All developed DGT of different types, including DGT with ferrihydrite for oxyanions (As, Se, Mo, V, Sb and W), were deployed in situ in seawater and groundwater around refineries and industrial areas in Oman. Soils and sediments in those areas were also collected for DGT deployments. The labile concentrations of Cr, Co, Ni, Cu, Cd, and Pb were generally low and not significantly different at all the sampling locations due to the formation of strong metals complexes with organic ligands that are less labile. The measured concentrations of labile V in all selected locations were much lower than the total V concentration in the filtered grab samples (CSol (0.45 μm filtered)) due to high levels of large colloidal ligands from crude oil. The low proportion of Ni labile species (11%-29%) was measured by (Nafion112)-DGT in all selected open wells because Ni is mainly complexed by negatively charged ligands and they were excluded by Nafion112 membrane. The labile Fe, Ni and Mn concentrations in Wells-1 and -2 were much higher than those in Well-3 and (RIE)’swells reflecting the occurrence of more intense oil and industrial contamination in the area. For coastal sediments near the refinery discharge point at Al Fahal port, the DGT measured labile concentrations of Fe, Ni, Cu, and V were higher near the discharge point. The DGT concentrations of Al, Fe and Mn in soils collected from SIR ranged from (12-22 μg/L), (14-63 μg/L) and (9-17μg/L) respectively, in line with the background level of those metals. For 15 selected soils, their Kd ranged from (1.8-33) ml/g for (Al, Cr, Mn, Fe, Ni and Cu). The Kd values of Pb were higher at soil locations (L2, L7, L8 and L11) of 266, 65, 43 and 55 gm/L respectively due to the higher metal retention by the solid phase through sorption reactions and low concentration in the soil solution. The obtained results suggest that risk assessment of sandy soils could be carried out using measurements of metals in soil solutions. However, devices such as DGT dynamic technique, which respond to the kinetics of supply, are essential to evaluate available metal in high pH and crude oil contaminated soils. Because DGT is a dynamic technique and it can be readily deployed in situ, in seawaters, groundwaters, soils, and sediments, it provides kinetic information directly in crude oil contaminated environmental systems and allows better understanding and risk assessments.

Abrupt, high-magnitude sea-level changes pose a major challenge to society and have, in the past, been significant drivers of coastal change. Traditionally, sea-level reconstructions from near-field regions - those close to or strongly influenced by current or former ice masses - depict long-term, millennial-scale sea-level changes associated with low-amplitude ice-sheet histories. Types of abrupt sea-level change, including meltwater pulses, tsunamis and storms, are not well studied in near-field regions, but such areas have potential to provide a suitable context for recording and identifying evidence of abrupt sea-level change. For example, unusually high sedimentation rates due to the presence of glaciers might promote the development of high-resolution records, while a dominant glacio-isostatic adjustment signal might facilitate improved registration and identification of globally significant episodes of abrupt sea-level rise. This thesis explores the efficacy of near-field regions in reconstructing abrupt sea-level change by using a combination of stratigraphic and dating methods at field sites in Scotland and Greenland. From southwest Scotland, a sub-centennially resolved, diatom-based sea-level reconstruction for the early Holocene constrains the timing and magnitude of three meltwater-induced sea-level accelerations in the c. 500 yrs prior to the 8.2 kyr BP event. Despite an inability of the 14C dating technique to confirm synchroneity of events, the three sea-level jumps overlap in age with other examples of abrupt change recorded in North Atlantic non-coastal and coastal archives, lending support to a three-event model of meltwater release from the Laurentide Ice Sheet as the driving mechanism responsible for the 8.2 kyr BP event. In Greenland, nearshore and freshwater stratigraphic records contain evidence of landslide- and iceberg-induced tsunami events in the mid and late Holocene. Field sites in Vaigat (Disko Bugt, West Greenland) preserve evidence of five tsunami events in the past 1500-2000 years, which is comparable to tsunami recurrence intervals described from sites on large subduction zone margins. A coastal lake at Innaarsuit also provides the first reported sedimentary evidence of an iceberg-generated tsunami in the mid Holocene. The thesis concludes by reflecting on the opportunities and challenges in reconstructing abrupt sea-level change from near-field settings.

Beaches composed of pebble to boulder-sized material are a common feature of rocky coastlines globally and provide effective protection against wave attack. However difficulties with the proximal deployment of wave gauges and measuring the transport of coarse clasts in the field has limited research in this area. The overarching aim of this thesis is to use contemporary ‘off-the-shelf’ technology in a series of interlinked, field-based experiments to improve quantitative understanding of relationship between coarse clastic beach dynamics and the nearshore wave conditions. In the first of the empirical chapters (Chapter 3), indigenous clasts implanted with motion loggers provided a unique insight into the threshold-entrainment within the littoral zone on: (1) an exposed macro-tidal field site in Abbotsham, UK and; (2) a fetch-limited system in Flathead Lake, USA. The threshold-entrainment was positively related to the power of waves that prevailed over the hour-long experiment and accurately predicted with the equations of Lorang (2000). The relationship between clast mass and power of individual incident waves linked to each entrainment event was more complex. There was the propensity of large clasts to occasionally become entrained by exceedingly weak waves. The processes behind this result remain unclear. Comprehensive experiments measuring variability in the concurrent wave conditions along the inner shore platform and offshore are presented in Chapter 4, along with daily longshore clast displacement and depth of activation measurements across the adjacent coarse clastic beach at Abbotsham. The longshore transport rate varies in concert with the longshore component of wave power, which is dependent on interactions between incident waves and shore platform morphology. These findings are used in Chapter 5 to model the (positive) longshore flux of clastic material towards the economically-valuable natural barrier, which has diminished in recent years. It was found that a disproportionately large fraction of positive transport was generated by storm events, the effectiveness of which was moderated by water depth. Net annual positive transport was predicted to increase with sea level rise and storminess. However, the increased influx was small in comparison to the volume of the barriers itself, and therefore unlikely to halt, or ameliorate future degradation. The experiments presented in this thesis provide new insight into nearshore wave transformations and the relationship between wave properties and clast transport at a time when sea level rise and the potential increase in storminess is threatening coastlines globally.

Dans le contexte national de remise en question de la gestion des risques littoraux, il apparaît nécessaire d’étudier la perception du risque de submersion marine des habitants afin d’améliorer la compréhension de leurs jugements et attitudes vis-à-vis des mesures préventives. Fondée sur une approche interdisciplinaire qui associe les apports de la psychologie sociale et environnementale à la géographie des risques, nous proposons une analyse de la perception du risque de submersion marine par les habitants de quatre communes littorales françaises, exposées à ce risque (Barneville - Carteret, Saintes-Maries-de-la-Mer, Châtelaillon-Plage et Sainte- Anne en Guadeloupe ). Une enquête, qui associe questionnaires et cartographies de perception, a été menée auprès de 318 habitants. Les données issues de l’enquête ont été traitées par des méthodes statistiques bivariées et multivariées. Les cartes de perception ont été digitalisées dans un SIG et ont fait l’objet de géotraitements. Nous mettons en évidence une tendance des participants à sous-évaluer l’exposition au risque de leur domicile et l’étendue des zones exposées à l’échelle de la commune. Nous proposons d’expliquer cette tendance par des facteurs liés à la connaissance du risque, l’expérience du risque, la localisation du domicile, le profil résidentiel et sociodémographique . / In the French national context of re-assessing coastal risk management, it seems necessary to study the pe rception of coastal flood risk by inhabitants in order to improve the understanding of their judgments and attitudes towards preventive policies. Based on an interdisciplinary approach that combines the contributions of social and environmental psychology to the geography of risks, we propose an analysis of the perception of coastal flood risk of the inhabitants of four French coastal communities exposed to this risk (Barneville-Carteret, Saintes-Maries-de-la-Mer, Châtelaillon- Plage and Sainte-Anne in Guadeloupe). A survey, which combines questionnaires and sketch maps, was conducted among 318 inhabitants. The survey data was processed by bivariate and multivariate statistical methods. The sketch maps were digitized in a GIS and geoprocessed. We highligh t a tendency of participants to underestimate the risk exposure of their homes and the extent of the exposed areas at the municipal level. We propose to explain this trend by factors related to risk knowledge, risk experience, home location, residential and socio-demographic profile.