Grundvatten är en viktig del av dricksvattenförsörjningen och en begränsad resurs, speciellt i kustområden. För att den framtida grundvattentillgången ska vara säkerställd är det viktigt att inkludera grundvatten i planeringsprocesser, där kommunerna har en bidragande roll. Därför är syftet att undersöka och analysera hur svenska kustkommuner arbetar med samt planerar för en hållbar tillgång på grundvatten som livsmedel, i enlighet med miljökvalitetsmålet Grundvatten av god kvalitet. En litteraturstudie med kompletterande fallstudier av kustkommunerna Norrtälje, Oskarshamn och Tyresö utgör underlag till rapporten. Grundvattnet påverkas av flertalet faktorer som geologins, klimatets och människors aktivitet. De grundvattenproblem som kommunala dokument behandlar i störst utsträckning är de som relaterar till den enskilda dricksvattenförsörjningen, vilket är ett område där möjligheterna till reglering inte utnyttjas. För de undersökta kommunerna hade bland annat kommunala vattenförsörjningsplaner kunnat bidra till en mer hållbar hantering av grundvattenresurser. / Groundwater is an important part of the drinking water supply and a limited resource, especially in coastal areas. To ensure future groundwater supplies, municipalities should include groundwater in their planning documents. Therefore, the aim is to investigate and analyse how Swedish coastal municipalities manage and plan for a sustainable groundwater drinking supply, according to the Swedish environmental quality objective Good-quality groundwater. The study is based on a literature review and three complementary case-studies of the Swedish coastal municipalities Norrtälje, Oskarshamn and Tyresö. There are many factors that affect the groundwater, such as geology, climate and human activities. The groundwater problems that municipal documents consider to the greatest extent are those related to private water supplies, particularly drilled wells. However, this is a field where the possibilities for regulation are not utilized amongst the municipalities. The case-studies indicate, among other things, that a document for water supply could contribute to sustainable groundwater management, at least for the investigated coastal municipalities.

Drought is a climatic event regarding prolonged "drier than normal" conditions. Precipitation deficits, crop-moisture stress, soil-water unbalance, sudden stream flow cut-offs and low carrying capacity of ecosystems are responses to drought. Drought can occur in humid to arid climates, however, drought is more severe in arid and semi-arid areas due to the fact that in those distinctive areas, water resources are extremely limited and restricted. Additionally, local ecologies and ecosystems in arid regions are very fragile. Once a water competition occurs, critical services of ecosystems such as pure water, recreation, and land productivity will be threatened. This research focuses on prolonged drought events that have been occurring more frequently in a coastal province of South Central Vietnam – named Binh Thuan. The study area is distinctive because its climate is characterized as one of the driest provinces in Vietnam. Annual rainfall in the North and near the coast of the province is less than 800 mm per year. During 6 months of dry season, there is almost no rain, or less than 50 mm. Due to precipitation deficits and high surface temperatures in recent years, meteorological droughts have occurred more frequently, and lasted longer, thereby stressing water resources for vegetation, wildlife, households, and industry. The occurrence of prolonged droughts has constrained economic activities in the coastal areas, especially agriculture and aquaculture. Furthermore, a long duration of dry conditions coupled with unsustainable land management (such as overgrazing), "drought-sensitive" soils in areas with sand and barren lands may introduce and accelerate risks of desertification processes (land productivity deterioration and unable to recover). This research uses geospatial technologies to monitor drought severity and drought impacts on land use and land cover. Chapter 1 is a brief introduction and literature review of the drought context in Binh Thuan Province to place the research questions and objectives in content. Chapter 2 discusses the occurrence of meteorological droughts in Binh Thuan Province, then proposes climatic indices able to monitor this type of drought. Chapter 3 focuses on explaining and assessing uneven dry conditions that stressed vegetation health in the study area. This chapter investigates spatiotemporal distributions and frequencies of prolonged agricultural droughts using remotely sensed data and anomalies of precipitation distribution. Results indicate that coastal areas in the North of Binh Thuan are subject to severe droughts. Chapter 4 assesses human impacts on land management and practices in the study area during drought periods. Results show that in recent years (2010 to present), local governments and residents have implemented strategies to prevent sand dominance and to adapt to water shortages during dry seasons, such as vegetative cover, crop rotation with drought-tolerant plants and wind breaks. Accuracy was assessed using field data collected in the summer of 2016, in conjunction with Google Earth imagery. In summary, this dissertation enhances understanding of drought events and impacts in Binh Thuan Province by considering different types of drought - meteorological and agricultural drought, and interactions of drought and human impacts upon land management and land practices during dry periods. Furthermore, findings and results of this research have demonstrated the effectiveness of remotely sensed datasets, and other geospatial technologies, such as geographic information systems, in modeling drought severity and in examining efforts and drought-adaptive practices of local residents. This work is a valuable foundation on which further studies can build to support policy development to protect and reserve soil-land productivity in Binh Thuan and other coastal regions of Vietnam affected by prolonged droughts. / Doctor of Philosophy / Drought is a temporal climatic event with "drier than normal" conditions. While drought can occur in any climates, it can be more extreme in arid and semi-arid areas where annual rainfall and water resources are limited. Depending on types of drought, its presences and impacts may differ: (1) meteorological drought relates to a decrease of average rainfall/snowfall may resulting in moisture stress, (2) hydrological drought leads to a reduction of streamflow and groundwater, and (3) agricultural drought influences soil-water-crop balance or vegetation health. Prolonged drought – abnormally long duration of dry conditions, coupled with unsustainable management in water and land practice may cause losses of land productivity, promote soil erosion, and result in sand dominance in coastal areas. These land degradation processes can lead to "a desert-like condition" in impacted areas. This research concerns drought and its impacts in a coastal province in South central Vietnam, Binh Thuan. The study area is distinctive because its climate is characterized as one of the driest provinces in Vietnam. Annual rainfall in the North and near the coast is less than 800 mm per year, and during the 6 months of the dry season, there is almost no rain, or less than 50 mm. Due to precipitation deficits and high surface temperatures in recent years, meteorological droughts have occurred more frequently and lasted longer, stressing water resources for vegetation, wildlife, households, and industry. Additionally, unsustainable land management, such as overgrazing, coupled with movements of sand and barren lands from the coast inland, have accelerated the risks of land degradation. This research applies an integration of geospatial technologies for monitoring drought severity and impacts on land management and illustrates how local people have adapted to droughts.

[pt] As zonas costeiras, de um modo geral, estão entre as áreas de maior risco no contexto da mudança climática, devido à concentração de ecossistemas importantes e recursos naturais típicos dessas áreas. Essas regiões abrigam uma grande parcela da população global em metrópoles urbanas, juntamente com uma concentração de estruturas críticas, como as indústrias portuárias, definindo uma alta exposição a ameaças incidentes. Devido à sua localização, as regiões litorâneas são afetadas por eventos críticos como a subida do nível do mar e outros fenômenos climáticos. Eventos de natureza extrema, como ciclones e tempestades costeiras, que somados à variação de marés podem causar ressacas e ondas gigantes. Tais eventos podem impactar essas áreas como erosão costeira, inundações, intrusão salina em corpos hídricos e desequilíbrio dos ecossistemas. A combinação dessas ameaças com o alto grau de exposição e a condição de vulnerabilidade de muitas das cidades litorâneas, pode resultar em perdas e danos relevantes. Esse alto risco define a importância de estudos sobre a vulnerabilidade de cidades costeiras nos dias atuais. Este estudo apresenta o resumo dos conceitos associados à mudança climática, vulnerabilidade e resiliência que foi baseado em uma análise crítica da literatura. Além disso, propõe uma estratégia metodológica para avaliar a vulnerabilidade climática de áreas urbanas costeiras, considerando tanto a população como os bens que estão em risco. A ferramenta de metodologia desenvolvida apresenta matrizes conceituais e inter-relações entre variáveis e indicadores. A integração de dimensões físicas e socioeconômicas, assim como as infraestruturas, instalações básicas e da capacidade de adaptação, permite aplicação deste método utilizando os dados selecionados para definição de prioridades nas políticas públicas. / [en] Coastal areas, in general, are among the areas most at risk in the context of climate change, due to the concentration of important ecosystems and natural resources typical of these areas. These regions house a large portion of the global population in urban metropolises, along with a concentration of critical structures, such as industrial ports, defining a high exposure to incident threats. Due to their location, coastal regions are affected by critical events such as sea level rise and other climate phenomena. Events of an extreme nature, such as cyclones and coastal storms, which, combined with tidal variations, can cause undertows and giant waves. Such events can impact these areas such as coastal erosion, flooding, saline intrusion into water bodies and imbalance of ecosystems. The combination of these threats with the high degree of exposure and the vulnerable condition of many coastal cities can result in significant losses and damages. This high risk defines the importance of studies on the vulnerability of coastal cities today. This study presents a summary of the concepts associated with climate change, vulnerability and resilience that was based on a critical analysis of the literature. Furthermore, it proposes a methodological strategy to assess the climate vulnerability of coastal urban areas, considering both the population and the assets that are at risk. The methodology tool developed presents conceptual matrices and interrelationships between variables and indicators. The integration of physical and socioeconomic dimensions, as well as infrastructure, basic facilities and adaptation capacity, allows the application of this method using selected data to define priorities in public policies

The objective of this study was to investigate the spatial and temporal distribution of black carbon (BC) and possible sources by analyzing BC contents in core and sediment trap samples collected from Kao-ping submarine Canyon and surficial sediments collected from Love River, Chianjen River, Kaohsiung Harbor, Kao-ping River and adjacent coastal area. In addition, sediment core and trap samples of Kao-ping submarine Canyon, and suspended solids of Kao-ping estuary were analyzed to estimate the BC loading from Kao-ping River and the flux in Kao-ping submarine Canyon. The concentrations of BC ranged from 0.38 to 3.29 mg g-1 in this study. The results we found in coastal sediments were comparable to those in Asia, but lower than those in America and Europe. Black carbon found in surficial sediments of D2, L1 and of stations from Love River, Chianjen River and Kaohsiung Harbor were contributed from vehicle emission or coal combustion. Correlation coefficients of BC versus total polycyclic aromatic hydrocarbon (PAH) concentrations, combustion PAHs, total organic carbon (TOC) and grain size were significant in the sediments of Kao-ping River adjacent coast. Regrading to the temporal distribution of BC in Kao-ping submarine Canyon, BC and PAHs increased in the deposited sediment after 1970, that was probably related to prosperous industrial activities for last decades in Taiwan. Surficial sediments could be grouped into three clusters by hierarchical cluster analysis (HCA). Results of principal component analysis (PCA) showed principal component 1 (PC 1) could explain 35 % of total variances. Significant PC 1 compound loadings were found mostly from high molecular weight PAHs which derived mainly from combustion processes. This result was supported by the significant correlation (p<0.05) of PC 1 scores versus BC concentrations which were also mainly derived from combustion. BC fluxes for sediment cores, S1 and S37, and sediment trap of Kao-ping submarine Canyon, 0.59 g m-2 yr-1, 2.03 g m-2 yr-1 and 23 g m-2 yr-1, respectively, were comparable to those reported for surficial sediments in literature. However, BC fluxes in this study were lower than those in the sediments from Mouth of Providence River, Palos Verdes Shelf and New England Harbors, but higher than those in pelagic sediments of the Pacific Ocean. In addition, we also measured BC concentrations in suspended solid samples to estimate loadings of Kao-ping estuary which ranged from 33 to 1765 kg day-1 with an average of 602 kg day-1. Annual BC loading of Kao-ping River was roughly estimated as 29.55¡Ñ104 tons which was lower than that of the Mississippi River.

Made available in DSpace on 2015-03-13T17:10:50Z (GMT). No. of bitstreams: 1 JannySDL_DISSERT.pdf: 6567283 bytes, checksum: 921d1baf83c48908caf6247b8a2ad1d1 (MD5) Previous issue date: 2013-02-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Issues concerning coastal regions, especially the beaches have sparked quite complex because studies are there that most people in the world has secured housing, mainly from the half of the last century, without concern for the natural dynamics of these environments, which have complex interactions of continental and oceanic, coastal responsible for changes in locations that can be perceived in a few years and sometimes even a few days or hours. The search took as main goal, analyze the Genipabu Beach, in the municipality of Extremoz/RN, fragile environment and rapid momentum, which has been occupied in a disorderly and unplanned. Carried out a beach monitoring through profiles beach environments: defined stages morphodynamics; realization of characterize hydrodynamic processes; identification of changes in the landscape. To this end, made necessary a survey from the bibliographic collection for theoretical and conceptual rationale. An empirical step for conducting the environmental characterization of hydrodynamics, leveling and topographic analysis of sediments (in laboratory), for observation of changes in features, influenced, and natural dynamics, anthropic action that increasingly comes taking the characteristics from the natural landscape. Underlines therefore the importance of academic studies in several areas in these environments, for setting up a coastal zoning giving public subsidies for managers for managing and planning the use and occupation of the coast in their areas / As quest?es referentes ?s regi?es costeiras, em especial as praias, t?m suscitado estudos bastante complexos, pois s?o nesses espa?os que a maioria das popula??es do mundo tem fixado moradia, principalmente, a partir da metade do s?culo passado, sem que haja uma preocupa??o com a din?mica natural desses ambientes, que possuem intera??es complexas de processos oce?nicos, continentais e costeiros respons?veis por mudan?as nos locais que podem ser percebidas em poucos anos e, em algumas vezes, at? em poucos dias ou horas. A pesquisa teve como objetivo principal, analisar a praia de Genipabu, no munic?pio de Extremoz/RN, ambiente fr?gil e de din?mica r?pida, que vem sendo ocupada de maneira desordenada e n?o planejada. Realizado um monitoramento da praia atrav?s de perfis praiais; Definimos os est?gios morfodid?micos; Realizamos uma caracteriza??o dos processos hidrodin?micos e identificamos as altera??es da paisagem. Para tanto, fez-se necess?rio um levantamento a partir do acervo bibliogr?fico para a fundamenta??o te?rico-conceitual. Uma etapa emp?rica para a realiza??o da caracteriza??o ambiental, da hidrodin?mica, do nivelamento topogr?fico e an?lise dos sedimentos (no laborat?rio), para a observa??o das modifica??es nas fei??es de praia, influenciada, al?m da din?mica natural, pela a??o antr?pica que cada vez mais vem descaracterizando a paisagem natural. Evidencia-se, portanto, a import?ncia de estudos nas diversas ?reas acad?micas nesses ambientes, para a configura??o de um zoneamento costeiro dando para os gestores p?blicos subs?dios para a gest?o e planejamentos do uso e ocupa??o do litoral nas suas ?reas

Au cours de leur cycle de vie, la plupart des espèces de poissons marins côtiers passent par des nourriceries littorales dont la qualité influence largement le succès du recrutement et donc le maintien de l’abondance de leurs populations. Or, la construction de ports entrain irrémédiablement une perte de fonction pour les habitats côtiers impactés. Dans ce contexte,l’objectif général de cette thèse était de voir si les zones portuaires peuvent malgré tout servir de nourriceries alternatives pour les poissons marins côtiers. Pour cela, les abondances des juvéniles de quatre espèces de sars, du genre Diplodus, ont d’abord été suivies dans cinq ports méditerranéens. Ceci a permis de montrer que ces espèces côtières peuvent s’installer et grandir avec succès dans les ports. La complexification de la structure 3D de l’habitat augmente sensiblement les abondances de juvéniles. Dans un second temps, la croissance, la condition et les niveaux de contamination desjuvéniles de deux espèces de sars (D. sargus et D. vulgaris) ont été comparés entre différents ports et habitats naturels de la rade de Toulon. Ceci a montré que la croissance et la condition des juvéniles peut être équivalente dans certains ports et dans les zones naturelles adjacentes, avec des niveaux de contamination faibles, même dans les zones les plus polluées. Enfin, la composition multi- élémentaire des otolithes des juvéniles de D. sargus et D. vulgaris a été comparée entre trois ports et deux zones naturelles de la rade de Toulon. Aucun élément chimique lié aux activités portuaires n’aété retrouvé en plus forte concentration dans les otolithes des juvéniles issus des ports. Il n’existe donc pas une signature unique caractéristique de l’ensemble des ports. La composition chimique des otolithes peut néanmoins être utilisée pour étudier la contribution relative des ports aux stocks d’adultes à condition de caractériser la signature de l’ensemble des habitats juvéniles potentiels. L’ensemble des résultats acquis indiquent que les ports peuvent être utilisés comme nourriceries alternatives par plusieurs espèces de poissons marins côtiers. Les projets d’ingénierie écologiquevisant à augmenter la complexité structurale des habitats portuaires sont des pistes intéressantes pour maintenir la biodiversité côtières et les stocks de poissons. / During their life cycle, most of the marine coastal fish species use nursery grounds which quality influence their recruitment and then the conservation of their populations. However, the construction of ports impair irremediably fish nursery function of the coastal areas impacted. The ultimate aim of the PhD research was to assess if ports could provide suitable alternative nursery habitats for coastal fish species. Firstly, abundances of the juveniles of four Diplodus species were surveyed in five marinas located along the French Mediterranean coast. This showed that coastal fishes can successfully settle and grow inside these artificialized coastal areas. Moreover, increasing the complexity of port habitats can considerably enhance their suitability for juveniles, especially at the youngest stages. Secondly, body condition, growth rate and metal contamination in the juveniles of two Diplodus species (D. sargus and D. vulgaris) were compared between different ports and natural areas in the Bay of Toulon. Juvenile growth and condition can be equivalent between fish collected from ports and from adjacent natural areas. Contamination levels in fish were low, even in highly polluted areas. Finally, otolith composition in the juveniles of D. sargus and D. vulgaris was investigated in three ports and two natural areas in the Bay of Toulon. None of the port related had systematically higher concentrations in otoliths from Diplodus juveniles collected in ports. Therefore, otolith microchemistry cannot provide a unique and reliable fingerprint discriminating ports and natural areas. Nevertheless, otolith microchemistry could provide an effective natural tag to determine the contribution of ports to adult stocks provided that a library of all potential juvenile habitat fingerprints is established. All these results confirm that ports can be used as alternative nursery habitats by marine coastal fishes. Ecological engineering projects aiming at increasing structural complexity of port habitats seem promising for biodiversity and fish stock conservation.

Auckland, Nouméa et Port-Vila connaissent un développement urbain très soutenu depuis au moins deux décennies, ce qui pourrait favoriser une privatisation progressive du littoral. La fermeture du rivage, résultant de la logique de marché, remettrait en cause des pratiques variées (de la pêche de subsistance à la promenade contemplative), fortement ancrées dans les mentalités. Une telle situation serait paradoxale pour ces trois agglomérations marquées par l'omniprésence de la mer. Elle menacerait également la durabilité de cités encore jeunes et en recherche d'identité et d'urbanité. Ce travail de recherche propose une grille d'évaluation de l'accès au littoral en milieu urbain, et interroge la mise en place d'une gouvernance basée sur un « droit au littoral ». Quels sont, dans chaque agglomération, les mécanismes d'ouverture et de fermeture de l'interface littorale ? Quels modes de régulation sont mis en place d'Auckland à Port-Vila pour garantir l'accès au bord de mer pour le plus grand nombre ? L'hypothèse que la puissance publique est déterminante pour garantir l'ouverture de l'interface littorale se vérifie-t-elle ? L'accès au littoral peut-il être régulé par d'autres acteurs que la puissance publique ? La démarche synchronique mis en œuvre dans cette thèse permet plus largement une réflexion sur les interactions entre l'urbanisation et l'interface littorale. / For at least two decades now, Auckland, Nouméa and Port-Vila have been experiencing a very strong urban development, that could involve the gradual privatization of the shore. The closure of the coast, due to the market strategies, could in these three cities jeopardize practises as widespread as subsistence fishing or simply walking by the sea. This would be a paradox in three cities surrounded by the sea. It would threaten the sustainability of those recent cities in search of identity and urbanity. This research aims at providing an evaluation grid of access to the coastal interface in urban areas, and interrogates for the creation of a governance based on a « right to the shore ». In each agglomeration, what mechanisms lead to the closure of the seafront? What are the measures developed to ensure public access to the coastline, and what are their spatial consequences? Is the public authority crucial to allow access to the shore? Furthermore, it will enable a comparison between three coastal management ways, and broadly a reflexion concerning urban and coast interaction.

Le changement climatique est incontestable et affecte les océans. L'observation à long terme d'indicateurs comme le plancton peut permettre l'étude de ces changements. Le suivi du plancton dans les eaux côtières d'Europe représente une source de données importante actuellement sous-exploitée et sur laquelle cette étude est basée. Des outils analytiques ont d'abord été conçus pour résoudre des divergences taxonomiques entre les données et pour réaliser l'analyse temporelle. L'étude du plancton à L4 de 1998 à 2007 révèle de profonds changements dans la composition phytoplanctonique des blooms de printemps et d'automne, et des variations à long terme dans l'abondance des taxa dominants du zooplancton. Le phytoplancton gouverne la succession saisonnière des larves méroplanctoniques. Les changements de température de surface et de vent contrôlent les variations temporelles des communautés planctoniques. Les variations spatio-temporelles du zooplancton ont été comparées à 4 sites de 1998 à 2007 : Ston (Mer du Nord), L4 (Manche), MC (Mer Tyrrhénienne ), et C1 (Mer Adriatique). La structure des communautés est globalement stable, la saisonnalité étant la principale source de variabilité à long terme. La chlorophylle a et le vent expliquent les variations de la communauté zooplanctonique à Ston et L4 alors que c'est la température à MC et C1. Cette étude confirme l'extrême adaptabilité des communautés zooplanctoniques à un environnement variable. Elle souligne l'importance de facteurs tels que taxonomie et échelle temporelle pour l'analyse de séries, et la nécessité de maintenir les séries à long terme pour le suivi de futurs changements dans le contexte du changement climatique. / Climate change is unequivocal and dramatic changes are under way in the world's oceans. Long-term observations of indicators such as plankton can provide a better understanding of these changes. Considerable efforts have been made to monitor plankton in European coastal waters and have produced a large amount of datasets yet to be fully exploited. Analytic tools were first developed to solve taxonomic discrepancies in datasets and for temporal analyses. Time series analysis of plankton at L4 from 1988 to 2007 reveals profound changes in the composition of the spring and autumn phytoplankton blooms, and long-term variations in abundance of the dominant zooplankton taxa. Phytoplankton is driving the seasonal succession of meroplanktonic larvae. Changes in sea surface temperature and wind conditions control temporal patterns of plankton communities. Spatio-temporal patterns of zooplankton are compared at 4 sites: Ston (northern North Sea), L4 (wes tern English Channel), MC (Tyrrhenian Sea), and C1 (Adriatic Sea) from 1998 to 2007. The communities structure is on average stable and seasonal variations are the main source of long-term variability. Chlorophyll a and wind are responsible for the community patterns observed at Ston and L4 whereas temperature is the main driver at MC and C1. This study supports evidences of the extreme flexibility of zooplankton communities in adjusting to a variable environment. We highlighted the importance of factors such as taxonomy and temporal scale on time series analysis, and the necessity of maintaining long-term series to monitor future changes in the context of climate change.

Les apports d’eaux souterraines (Submarine Groundwater Discharge : SGD) peuvent constituer des apports considérables d'eau et de nutriments ou de contaminants en zone côtière. Le suivi des radio-éléments (radon, radium) dans ces zones permet de tracer les apports de SGD et leurs bilans de masse permettent de quantifier leurs flux. Cette méthode est utilisée depuis des années, mais les termes des bilans aux interfaces restent difficiles à appréhender. L'objectif de cette thèse est d'apporter des précisions sur ces termes afin de permettre une meilleure quantification des flux de SGD. Pour l'interface air-eau, les flux de dégazage du radon vers l'atmosphère ont été estimés pour différentes conditions de vent sur l’étang de Berre. Un dégazage permanent, même sans vent, a été mis en évidence. Pour l'interface sédiment-eau, nous décrivons une méthode de calcul et d’évaluation du flux diffusif du radon et proposons une nouvelle approche pour estimer celui du radium. Dans la lagune de Mar Menor, les flux de SGD estimés sont 5 à 200 fois plus élevés que les apports d'eau par les rivières et sont majoritairement causés par de la recirculation d’eau à travers les sédiments. Pour la première fois les suivis de radio-éléments ont été combinés à un modèle hydrodynamique, ce qui a permis de localiser précisément les SGD. L'étude du système karstique de la source de la calanque de Port-Miou a mis en évidence un système bicouche de la colonne d'eau. La combinaison des bilans en radio-éléments, d'eau et de sel nous a permis d'estimer un débit de la source très proche de celui mesuré par différence de pression, attestant ainsi de la fiabilité de cette méthode pour les systèmes karstiques. / Submarine Groundwater Discharges (SGD) may represent important inputs of water, nutrients as well as contaminants to the coastal zone. Monitoring radionuclides (radon, radium) in those areas allows to trace SGD inputs while their fluxes may be quantified through their mass balances. This method has been used for many years, even though the terms from the mass balance at these interfaces remain difficult to manage. The objective of this thesis is to develop methods to better describe and evaluate these terms, in order to get a better quantification of SGD fluxes. For the air-water interface, the radon atmospheric fluxes have been estimated for different wind conditions on the Berre lagoon. A permanent flux, even without wind, has been highlighted. For the sediment-water interface, new methods are proposed here in order to calculate and evaluate the radon diffusive flux, as well as a new approach for estimating the radium diffusive flux. In the Mar Menor, the estimated SGD fluxes are 5 to 200 times higher than water river inputs and are predominantly caused by lagoon water recirculation through sediments forced by tidal pumping. For the first time, the monitoring of radionuclides in this lagoon was combined to a hydrodynamic model, allowing to locate precisely the SGD inputs. The study of the karstic spring of the Port-Miou calanque shows a two-layer system in the water column. The combination of radionuclides, water and salt mass balances leads to calculate a spring flux similar to the one measured by pressure gradient, which confirms the reliability of this method for karstic systems.

En tant qu'événement parmi les plus puissants de l'histoire éruptive récente de Lombok, les matériaux volcaniques expulsés par le volcan Samalas en 1257 couvrent toute l'île de Lombok et sont largement répandus dans sa partie est. Près de 800 ans après l'éruption, l'impact géomorphologique de cette éruption sur l'île reste inconnu, alors que ses conséquences climatiques et sociétales globales sont désomais mieux comprises. Une combinaison des informations stratigraphiques, des topographies actuelles, des mesures géophysiques, des sources écrites locales, analyse de laboratoire et informatique ont été utilisées pour obtenir des informations détaillées sur les impacts géomorphologiques de l'éruption du volcan Samalas sur la zone côtière le long du détroit d' Alas, Nusa Tenggara Ouest, Indonésie. Cette étude fournit de nouvelles informations relatives à l'impact géomorphologique d'une éruption volcanique majeure dans des zones côtières, dans ce cas-ci, dans la partie est de Lombok, ainsi que sur la côte ouest de Sumbawa. En premier lieu, les résultats de l'étude montrent que le paysage de la partie est de Lombok est encore évolué jusqu'à présent. Le volume de matière volcanique de l'éruption des Samalas reste à environ 14% du volume initial. Deuxièmement, la découverte de Babad Suwung fournit une description supplémentaire de l'éruption des Samalas sur l'île de Sumbawa et pourraient être la plus ancienne observation visuelle de déferlantes pyroclastiques après celles de Pline Ie Jeune en 79 pour le Vésuve. Enfin, l'éruption du volcan Samalas en 1257 a prouvé avoir déclenché un tsunami mineur qui a frappé l'île de Belang, sur la côte ouest de Sumbawa. / As the most powerful event in Lombok’s recent eruptive history, volcanic materials thatwere expelled by the Samalas volcano in 1257 CE covered the entire of Lombok Islandand are widespread in its eastern part. Almost 800 years after the eruption, the geomorphological impact of this eruption on the island of Lombok remains unknown,whereas its overall climatic and societal consequences are now better understood. Acombination of stratigraphic information, present-day topography, geophysical measurement with two-dimensional resistivity profiling technique, local written sources,as well as laboratory and computational analysis, were used to obtain detailed information concerning geomorphic impacts of the 1257 CE eruption of Samalas volcano on the coastal area along the Alas Strait in West Nusa Tenggara Province, Indonesia. This study provides new information related to the geomorphic impact of amajor eruption volcanic in coastal areas, in this case, on the eastern part of Lombok and the western coast of Sumbawa. In the first place, the study result shows that since the 1257 CE eruption, the landscape on the eastern part of Lombok is still evolved untilthe present time. The volume of the 1257 CE volcanic material remains about 14% from the initial volume. Secondly, the discovery of Babad Suwung provides additional explanation of Samalas eruption and may become the oldest visual observation of pyroclastic surges and volcanic fallout, following those by Pliny the Younger in 79 CE. Finally, the 1257 CE eruption of Samalas volcano has proven triggered a minor tsunami that hit Belang Island, on the west coast of Sumbawa.