Shallowly-buried channel systems have been imaged on the New Jersey Shelf with high-resolution seismic imaging. These channels formed as riverine systems that occupied the exposed shelf during the Last Glacial Maximum, ~18 ka. Subsequent sea level rise ~15-12 ka modified the valleys, forming estuaries and filling the channels with estuarine sediments. The infill sediments within the channel provide evidence for the response of the shelf to the Late Pleistocene glacio-eustatic sea level rise, but little work has been done on samples from these strata. This study aids in the ground-truthing of previous stratigraphic results by analyzing the cores collected within the infill sediments. The seismic stratigraphy of fill sediments from the mid-shelf and outer-shelf channels are structurally dissimilar. The mid-shelf channel fill stratigraphy is dominated by finely-laminated U-shaped reflectors throughout the section, with cut and fill geometries. In contrast, the outer shelf channel fill stratigraphy is a well-ordered sequence of 4 identifiable, primarily flat-lying seismic units. We collected five cores in mid-shelf channels (~30 m water depth), one in an outer shelf channel (~80 m of water depth) and one core in the trangressive ravinement surface. Cores were logged for density and seismic velocity. Grain size analysis was conducted by settling column and laser particle size analyzer. Radiocarbon analysis of the stratigraphy was conducted with the shell fragments and organic mud within the samples. The foraminiferal assemblages aided in determining the depositional environment. Using these data I investigated the differences in depositional environment of the mid- and outer-shelf channels systems, and consider these results in the context of sedimentary models for estuarine processes. The radiocarbon dates and foraminiferal are consistent with channel infill in an estuarine environment. Grain size and density log data indicate that the mid-shelf channel fills are sandier than the outer-shelf channel fills, which leads me to infer that the sediment from the mid-shelf channels was deposited in a higher energy environment than that of the sediment in the outer shelf channels. The stratigraphic differences and locations of the channel systems are similar to the Zaitlin (1994) model of incised valley infill, but infill of the mid-shelf channel system could possibly be the result of a catastrophic meltwater flood event occurring ~14 ka as glacial lakes to the north broke their dams and flooded the mid-shelf. / text

The evidence of a flood wave passing through a catchment remains visible even for a long time after it occurs. The morphological update in the channel and floodplains, together with the processes related to the mass transport within the aquatic environment, can be regarded as flood event evidence. The advancement in hydroinformatics brought the development of numerical modeling as a tool for the solution of broad hydrological tasks. Thanks to the scenario modeling, flood events with interconnected processes can be explored in detail. This thesis is broadly focused on the mass transport initialization issue both in the polluted and clear middle-European water environments. The aim of the thesis is the evaluation of the principal issues connected with the mass transport initialization based on complex and integrated numerical modeling. The thesis brings original datasets resulting from several case studies. The aim of the thesis is also to bring a comparative study of methodological approaches evaluating the possibilities and limits regarding the accuracy of inputs vs. outputs and computational time requirements. This thesis also brings several useful comparisons and innovative solutions design. The mass transport initialization issue is solved in both balance and event-scale processed- based models....

Ce travail de thèse focalise sur le fonctionnement du réseau microbien de la lagune de Thau à travers une approche « Réseau » ayant permis l’étude simultanée de l’ensemble des groupes microbiens (21 groupes) des virus au microzooplancton. La croissance et la mortalité des micro-organismes ont été étudiées expérimentalement lors de plusieurs saisons puis d’une étude en mésocosme. Nous avons déterminé les proportions de mortalité dont sont responsables le microzooplancton et les virus au travers de la lyse virale. Un suivi in situ puis en mésocosme dans la lagune de Thau nous a permis d'observer la réponse des composantes du réseau microbien à un forçage typiquement Méditerranéen, la crue.Il apparait que les bactéries hétérotrophes ont les plus fortes croissances allant jusqu’à 2,18 jour-1. La croissance pour divers groupes pico- et nano-phytoplanctoniques était inférieure à 1,5 jour-1. La cause majeure de mortalité des différents groupes de micro-organismes étudiés est la prédation du microzooplancton (> 90% en moyenne), tandis que la lyse virale semble être un processus sporadique et nettement moins important. Le fait que les taux de prédation observés soient très proches des taux de croissance de différents micro-organismes suggère que le réseau microbien étudié présente une forte efficacité de transfert de la biomasse vers les niveaux trophiques supérieurs.Dans ce contexte, la crue provoque à court terme une diminution de la croissance microbienne et du broutage, alors qu’elle déclenche la lyse virale chez certains groupes. Cependant, la réactivité de ce réseau permet un rétablissement rapide indiquant une forte capacité de résilience de ce système. / The aims of this thesis work were to shed new lights on the functioning of the microbial food web (MFW) in the Thau coastal lagoon through a “global approach” that permit us to study simultaneously the entire MFW components (21 groups) from viruses to microzooplankton. Growth and mortality of microorganisms were studied experimentally along seasons and during a mesocosm experiment. We particularly focus on mortality due to microzooplankton (<200µm) grazing and viral lysis. Responses of the different components of the MFW under a typical Mediterranean forcing, flash flood, was also studied during an in situ monitoring and a mesocosm experiment in the Thau Lagoon.In conclusion, it appears that heterotrophic bacteria show the highest growth rates (until 2.18 day-1). Growth rates of pico- and nanophytolankton groups were always lower than 1.5 day-1. The major cause of mortality of the different group studied, reaching on average 90%, was due to the predation by the microzooplankton. Mortality due to viral lysis appeared to be a “sporadic processes”, less important than microzooplankton grazing indeed. In addition, the observed grazing rates or bacterivory were close to growth rates of microorganisms, suggesting an efficient trophic transfer of the microbial biomass towards higher trophic levels.River flash flood; an important forcing in the Mediterranean coastal zone; triggered on a short time scale, a decrease in growth and grazing rates of microorganisms whereas viral lysis was enhanced. However, the important dynamics of this studied MFW allowed the rapid reestablishment of growth and grazing rates, indicating a strong resilience capability of this system.

At the Leibniz Institute of Ecological and Regional Development (IOER) in Dresden scientists work to investigate landscape dynamics and their cumulative environmental effects. Historic flood maps are important sources of information when evaluating past floods and making comparison with more recent ones. There exist two maps documenting historic Elbe floods in Saxony in 1845 and 1890, and their contents have been analysed and compared with recent flood data of 2002. This paper will discuss both the specific characteristics of such unique historic maps and the problems of their incorporation into the GIS workflow, including the derivation of land use from the maps and its verification. Geodata overlay of various flood events allows statements to be made about the development of flood risk in spatially differentiated areas. This valuable geodata has been placed on the internet for access by the public, planners and researchers.

At the Leibniz Institute of Ecological and Regional Development (IOER) in Dresden scientists work to investigate landscape dynamics and their cumulative environmental effects. Historic flood maps are important sources of information when evaluating past floods and making comparison with more recent ones. There exist two maps documenting historic Elbe floods in Saxony in 1845 and 1890, and their contents have been analysed and compared with recent flood data of 2002. This paper will discuss both the specific characteristics of such unique historic maps and the problems of their incorporation into the GIS workflow, including the derivation of land use from the maps and its verification. Geodata overlay of various flood events allows statements to be made about the development of flood risk in spatially differentiated areas. This valuable geodata has been placed on the internet for access by the public, planners and researchers.:1. Introduction 2. Historic Flood Events 3. Maps of Historic Flood Events 4. Digital Processing of Historic Maps 5. Results and Conclusions of GIS Analysis 6. Interactive Map Presentation