Incidental bycatch in gillnets is a substantial threat to small cetaceans. Using Acoustic Deterrent Devices, “pingers”, have successfully reduced bycatch of harbour porpoises in gillnets. However, seals can use pingers as “dinner-bells” to easier find gillnets in order to raid and destroy them, further aggravating the existing conflicts between seals and coastal fisheries. Therefore, in the present study, the efficiency of two alleged “seal-safe” pingers, an experimental Banana pinger “SSB” and a Future Oceans F70 pinger “FO”, in deterring harbour porpoises from the vicinity of gillnets and thereby reducing bycatch in commercial gillnet fisheries, was tested. This was done by deploying click detectors, “C-PODs”, recording Detection Positive Minutes per hour, at each end of gillnets, provided with the two pinger types or no pingers at all. Bycatch instances were recorded into logbooks by participating fishermen and verified using video footage from on-board video cameras. Results showed that video monitoring was a reliable method for verifying the number of bycatches of porpoises and seals, but not seabirds, recorded in the fishermen’s logbooks. The experimental SSB pingers and the FO pingers significantly reduced porpoise presence, measured as Detection Positive Minutes per hour in the vicinity of the nets, compared to gillnets without pingers. However, the sample size was too small to yield a significant result regarding the bycatch reducing efficiency and dinner bell effect of the experimental pingers. Nevertheless, bycatch trends suggest that pingers did in fact reduce porpoise bycatch. Although both successful, FO pingers were slightly more efficient in deterring porpoises than SSB pingers. The SSB pinger sounds had bigger directionality variations than the FO pinger, which may have affected its deterrent effects. Therefore, additional trials are needed to further investigate this aspect.

The atmospheric boundary layer (ABL) is the lowest layer of the atmosphere where surface effects are felt on time scales of about an hour. While its properties are determined by the surface characteristics, season and synoptic conditions, they in turn determine convective cloud properties and are required for the representation of cloud processes in atmospheric models. Further, interaction of the ABL with the surface layer of the ocean is a key component of ocean-atmosphere coupling. ABL characteristics over ocean surrounding the sub-continent become very important for understanding the monsoon processes during the monsoon season because the roots of many monsoon systems, that give rain to India, are over there. In this thesis data used are from three major field experiments namely the Bay of Bengal Monsoon Experiment (BOBMEX, 1999), Arabian Sea Monsoon Experiment (ARMEX, in two phases, ARMEX-I during 2002 and ARMEX-II in 2003), and Continental Tropical Convergence Zone (CTCZ) experiment (Pilot in 2009) which were carried out under the Indian Climate Research Programme (ICRP). While there have been few studies on ABL characteristics for individual cruises, a comprehensive study considering all available radiosonde data from the above cruises has been missing. This study fills this gap and focuses on the vertical structure of ABL using more than 400 high resolution Vaisala GPS radiosonde data collected over Bay of Bengal and Arabian Sea. The study attempts at first to look at the ABL characteristics of individual cruises and then compare and contrast them over the Bay of Bengal and Arabian Sea. ABL height Hm, estimated by using virtual potential temperature (θv) profile, shows diurnal variation during weak phase of convection while maximum in early morning during active phase of convection. Different variables i.e. moist static energy (h), specific humidity (q), convective available potential energy (CAPE), virtual potential temperature (θv) and equivalent potential temperature (θe) also differ during weak and active convection periods. Conserved variables mixing line approach gives the height up to which ground thermals penetrate in the vertical. This height, denoted by MH that represents the actual ABL height, is 2-3 times larger than Hm when shallow convective clouds are present. In general both Hm and MH are 20-30% larger over Arabian Sea compares to that over Bay of Bengal. Comparison of surface convective available potential energy (CAPE) and equivalent potential temperature (θe) between normal and deficit monsoon years shows that convective instability was as large in deficit years. This means that dynamic and not thermodynamics, controlled the occurrence of convection.

Les modèles numériques d'océans régionaux tridimensionnels sont basés sur la résolution des équations primitives et utilisent pour la plupart des méthodes de résolution eulérienne de type différences finies sur des grilles décalées. Ces modèles doivent représenter fidèlement les transports et transferts d'énergie. L'amélioration de ces modèles numériques exige donc (i) l'identification des processus prépondérants, notamment en terme de dissipation, dans ces transferts et (ii) la construction de méthodes numériques respectant un certain nombre d'équilibres. La première partie du travail se concentre sur la propagation des ondes externes et internes de gravité. Nous nous intéresserons en premier lieu à la stabilité de la séparation en mode rapide (barotrope) et lents (baroclines) et montrons qu'elle peut être ameliorée en levant certaines hypothèses traditionnellement effectuées. Dans un second temps, nous étudions l'impact de la discrétisation (ordre des schémas, grilles décalées ou non) sur la propagation des ondes internes de gravité provenant du couplage vitesse pression. Une décomposition en modes verticaux nous permet également de proposer un schéma espace temps très efficace. La seconde partie étudie en détail les schémas d'advection de quantité de mouvement et de traceurs, tout particulièrement dans l'objectif d'une réduction de la diffusion diapycnale (diffusion dans les directions orthogonales aux couches de densité constante). Ce travail nous amène tout d'abord à porter notre attention sur les schémas d'advection verticaux souvent négligés au regard de la dimension horizontale. Les bonnes propriétés d'un schéma compact (et de ses variantes espace temps et monotones) sont mises en avant. Enfin nous analysons le comportement multidimensionnel de ces schémas d'advection. / Three-dimensional regional ocean numerical models are based on solving the primitive equations and mostly use Eulerian finite differences methods of resolution on staggered grids. These models must accurately represent transports and energy transfers. Improving these numerical models therefore requires (i) the identification of predominant process, particularly in terms of dissipation in these transfers and (ii) the construction of numerical methods respecting a number of balances. The first part of the work focuses on the propagation of external and internal gravity waves. We focus primarily on the stability of the separation in fast mode (barotropic) and slow (baroclinic) and show that it can be improved by removing certain assumptions traditionally made. In a second step, we study the impact of the discretization (order of schemes, staggered grids or not) on the propagation of internal gravity waves coming from the coupling velocity pressure. A decomposition into vertical modes also allows us to offer a highly effective space-time scheme. The second part examines in detail the numerical advection schemes of momentum and tracers, especially with the aim of reducing the diapycnal diffusion (diffusion in the orthogonal direction of constant density layers). This work leads us first to focus our attention on the vertical advection schemes often overlooked in front of the horizontal dimension. The good properties of a compact schema (and its space-time and monotonous variants ) are highlighted. Finally we analyze the multidimensional behavior of these advection schemes.

Continental shelves located along eastern boundary currents occupy relatively small volumes of the world’s oceans, yet are responsible for a large proportion of global primary production. The Oregon coast is among these ecosystems. Recent analyses of dissolved oxygen at shallow depths in the water column has suggested increasing episodes of hypoxia and anoxia, events that are detrimental to larger macro-faunal species. Microbial communities, however, are metabolically diverse, capable of utilizing alternative electron donors and acceptors, and can withstand transient periods of low dissolved oxygen. Understanding the phylogenetic and metabolic diversity of microorganisms in these environments is important for assessing the impact hypoxic events have on local and global biogeochemistry. Several molecular ecology tools were used to answer questions about the distribution patterns and activities of microorganisms residing along the coast of Oregon in this dissertation. Ribosomal rRNA fingerprinting and sequence analyses of samples collected during 2007-2008 suggested that bacterial community structure was not substantially influenced by changes in dissolved oxygen. However, substantial depth dependent changes were observed, with samples collected in the bottom boundary layer (BBL) displaying significant differences from those collected in the surface layer. Phylogenetic analyses of bacterial rRNA genes revealed novel phylotypes associated with this area of the water column, including groups with close evolutionary relationships to putative or characterized sulfur oxidizing bacteria (SOB). Analysis of metagenomes and metatranscriptomes collected during 2009 suggested increasing abundances of chemolithoautrophic organisms and their activities in the BBL. Thaumarchaea displayed significant depth dependent increases during the summer, and were detected at maximal frequencies during periods of hypoxia, suggesting that nitrification maybe influenced by local changes in dissolved oxygen. Metagenomic analysis of samples collected from 2010 revealed substantial variability in the metabolic potential of the microbial communities from different water masses. Samples collected during the spring, prior to upwelling clustered independently of those collected during the summer, during a period of upwelling, and did not display any clear stratification. Samples collected during the summer did cluster based on depth, consistent with previous observations, and increases in the relative abundances of chemolithotrophic gene suites were observed in the BBL during stratified conditions, suggesting that the metabolic potential for these processes is a repeatable feature along the Oregon coast. Overall, these observations suggest that depth impacts microbial community diversity, metabolic potential, and transcriptional activity in shallow areas of the Northeast Pacific Ocean. The increase in lithotrophic genes and transcripts in the BBL suggests that this microbial community includes many organisms that are able to use inorganic electron donors for respiration. We speculate that the dissolved organic material in the BBL is semi-labile and not available for immediate oxidation, favoring the growth for microorganisms that are able to use alternative electron donors. / Graduation date: 2012

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / Better use and recycling of fresh water, which often recharges the oceans, would reduce man's disruption of nature to increase his supply of potable water. The global distribution of water, desalination, water reclamation and recycling, the roles of soils and plants in recycling and urban misuse of water are discussed. Man can increase his supply of food and good fresh water by recycling and nutrient balance, which imply living off his wastes. Intimate involvement of soils and plants in the production of fresh water and food is clear. Soils and plants should be equally involved in converting our waste water into potable water and useful nutrients. Numerous examples of how this may be done and how it is being done are presented.

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering, 1997. / "September 1997." "Funding was provided by National Science Foundation Grant OCE-9201286, National Science Foundation Graduate Fellowship Program, and the JOI/USSAC Ocean Drilling Graduate Fellowship Program." Includes bibliographical references (p. 152-153).

Our understanding of microbial evolution is largely dependent on available genomic data of diverse organisms. Yet, genome-sequencing efforts have mostly ignored the diverse uncultivable majority in favor of cultivable and sociologically relevant organisms. In this thesis, I have applied and developed cultivation independent methods to explore microbial diversity and obtain genomic data in an unbiased manner. The obtained genomes were then used to study the evolution of mitochondria, Rickettsiales and Haloarchaea. Metagenomic binning of oceanic samples recovered draft genomes for thirteen novel Alphaproteobacteria-related lineages. Phylogenomics analyses utilizing the improved taxon sample suggested that mitochondria are not related to Rickettsiales but rather evolved from a proteobacterial lineage closely related to all sampled alphaproteobacteria. Single-cell genomics and metagenomics of lake and oceanic samples, respectively, identified previously unobserved Rickettsiales-related lineages. They branched early relative to characterized Rickettsiales and encoded flagellar genes, a feature once thought absent in this order. Flagella are most likely an ancestral feature, and were independently lost during Rickettsiales diversification. In addition, preliminary analyses suggest that ATP/ADP translocase, the marker for energy parasitism, was acquired after the acquisition of type IV secretion systems during the emergence of the Rickettsiales. Further exploration of the oceanic samples yielded the first draft genomes of Marine Group IV archaea, the closest known relatives of the Haloarchaea. The halophilic and generally aerobic Haloarchaea are thought to have evolved from an anaerobic methanogenic ancestor. The MG-IV genomes allowed us to study this enigmatic evolutionary transition. Preliminary ancestral reconstruction analyses suggest a gradual loss of methanogenesis and adaptation to an aerobic lifestyle, respectively. The thesis further presents a new amplicon sequencing method that captures near full-length 16S and 23S rRNA genes of environmental prokaryotes. The method exploits PacBio's long read technology and the frequent proximity of these genes in prokaryotic genomes. Compared to traditional partial 16S amplicon sequencing, our method classifies environmental lineages that are distantly related to reference taxa more confidently. In conclusion, this thesis provides new insights into the origins of mitochondria, Rickettsiales and Haloarchaea and illustrates the power of cultivation independent methods with respect to the study of microbial evolution.

Distributed coordination of multi-agent systems (MASs) has been widely studied in various emerging engineering applications, including connected vehicles, wireless networks, smart grids, and cyber-physical systems. In these contexts, agents make the decision locally, relying on the interaction with their immediate neighbors over the connected communication networks. The study of distributed coordination for the multi-agent system (MAS) with constraints is significant yet challenging, especially in terms of ubiquitous uncertainties, the heavy communication burden, and communication delays, to name a few. Hence, it is desirable to develop distributed algorithms for the constrained MAS with these practical issues. In this dissertation, we develop the theoretical results on robust distributed model predictive control (DMPC) algorithms for two types of control problems (i.e., formation stabilization problem and consensus problem) of the constrained and uncertain MAS and apply robust DMPC algorithms in applications of cooperative marine vehicles. More precisely, Chapter 1 provides a systematic literature review, where the state-of-the-art DMPC for formation stabilization and consensus, robust MPC, and MPC for motion control of marine vehicles are introduced. Chapter 2 introduces some notations, necessary definitions, and some preliminaries. In Chapter 3, we study the formation stabilization problem of the nonlinear constrained MAS with un- certainties and bounded time-varying communication delays. We develop a min-max DMPC algorithm with the self-triggered mechanism, which significantly reduces the communication burden while ensuring closed-loop stability and robustness. Chapter 4 investigates the consensus problem of the general linear MAS with input constraints and bounded time-varying delays. We design a robust DMPC-based consensus protocol that integrates a predesigned consensus protocol with online DMPC optimization techniques. Under mild technical assumptions, the estimation errors propagated over prediction due to delay-induced inaccurate neighboring information are proved bounded, based on which a robust DMPC strategy is deliberately designed to achieve robust consensus while satisfying control input constraints. Chapter 5 proposes a Lyapunov-based DMPC approach for the formation tracking control problem of co-operative autonomous underwater vehicles (AUVs) subject to environmental disturbances. A stability constraint leveraging the extended state observer-based auxiliary control law and the associated Lyapunov function is incorporated into the optimization problem to enforce the stability and enhance formation tracking performance. A collision-avoidance cost is designed and employed in the DMPC optimization problem to further guarantee the safety of AUVs. Chapter 6 presents a tube-based DMPC approach for the platoon control problem of a group of heterogeneous autonomous surface vehicles (ASVs) with input constraints and disturbances. In particular, a coupled inter-vehicle safety constraint is added to the DMPC optimization problem; it ensures that neighboring ASVs maintain the safe distance and avoid inter-vehicle collision. Finally, we summarize the main results of this dissertation and discuss some potential directions for future research in Chapter 7. / Graduate / 2023-04-19

L’évolution du droit international contemporain conduit souvent à poser la question de sa fragmentation. L’existence, dans le droit de la mer, d’une double approche, universelle et régionale, contribue à alimenter ce débat.La présente recherche s’intéresse aux relations, en termes d’interactions, que l’universalisme et le régionalisme entretiennent dans le droit de la mer. Elle tente plus précisément d’en comprendre les mécanismes et les enjeux.Dans un premier temps, l’étude est consacrée à l’analyse des interactions normatives et institutionnelles. Il est observé que le dédoublement de l’ordre des mers est plus apparent que réel, universalisme et régionalisme étant engagés dans des relations montrant leur entrelacement.Dans une seconde phase, l’analyse se tourne vers l’impact de ces interactions, non seulement sur les approches universelle et régionale, mais également sur l’ordre des mers. Il apparaît, en effet, que les relations entre ces deux dynamiques influencent décisivement la gouvernance des espaces marins dans leur ensemble. C’est ce dont rendent compte tant la création que l’application effective des règles chargées d'assurer cette gouvernance internationale. / The evolution of contemporary international law often leads to the question of its fragmentation. The presence, in the Law of the Sea, of both a universal and a regional approach contributes towards nourishing this debate.The present research focuses on the relationships, in terms of interaction, between universalism and regionalism within the Law of the Sea. It attempts especially to understand the mechanisms of these interactions and their stakes.At first, the study is devoted to the analysis of normative and institutional interactions. One can observes that the cleavage of the legal order of the seas is more apparent than real, since universalism and regionalism are engaged in relationships showing their intertwining nature.Secondly, the study is turned towards the impact of these interactions, not only on the universal and regional approaches, but also on the legal order of the Sea. Indeed, it appears that the relations between these two components of the Law of the Sea, influence in a decisive way the governance of the oceans as a whole. This influence can be seen in the creation as well as in the effective application of the rules of this international governance.

Thesis (Master of Military Studies)--USMC Command and Staff College, 2008. / Title from PDF title screen. Text document in PDF format. Includes bibliographical references (p. 21-22).