The fluid circulation patterns, temperature distributions, and density gradients of the South Arm of the Great Salt Lake were modeled using the Estuary, Lake, and Coastal Ocean Model (ELCOM) from the Centre for Water Research at the University of Western Australia. The effort is part of a research study in conjunction with the United States Geological Survey (USGS) and the Utah Water Research Lab located at Utah State University. The model was simulated for several different cases of salinity gradients over different time periods, using temperature and wind data from 2006. The model is then used to identify factors which may provide a transport mechanism of heavy metals such as selenium and mercury from the sediment layers to the upper brine layers where it is introduced into the food chain.

Coastal karst aquifers are important water resources, often providing the only source of freshwater to coastal communities for agriculture, industrial usage and human consumption. In order to implement management strategies and preventative measures for future perseveration of this resource, it is imperative to understand how coastal groundwater conditions are controlled by the interaction of freshwater/seawater on local and regional scales, but also over recent and past time periods. However, there is a limited resource of published hydrological data on recent aquifer conditions. In the Yucatán Peninsula and other anchialine environments, this lack of information inhibits the understanding of the spatial and temporal interaction of the meteoric and marine water masses. Documenting how the aquifer is responding to forcing mechanisms such as large precipitation events, seasonal cycles and short-term sea level rise (e.g. storm surge) will assist in understanding modern aquifer condition but also the interpretation of paleo-records. Utilization of water level and salinity sensors in strategic positions in the aquifer demonstrate that meteoric water mass salinity varies over wet and dry seasons with the movement of the halocline, but also on a short-term basis though large rainfall events. Salinity in the meteoric water mass is influenced by mixing with the marine water mass during intense precipitation events associated with Hurricane Ingrid (2013), Tropical Storm Hanna (2014) and a series of unnamed events in 2015. During wet periods, induced flow from increase precipitation causes turbulent mixing with the marine water mass, increasing salinity in the upper meteoric lens. On the contrary, during dry periods, mixing is reduced, therefore making the meteoric lens less saline. This contemporary understanding of meteoric/marine water mass dynamics can be applied to developing and calibrating the geochemical record of calcite rafts, calcite precipitation at the air-water interface of cave pools, as a hydrological proxy for aquifer conditions. Our monitoring of calcite raft formation, deposition and geochemistry shows that raft accumulations (e.g., raft piles/cones) can offer a good paleoenvironmental archive of changing hydrological conditions. Based on a 2-year observational record, results indicate that calcite raft precipitation/formation occurs continuously but with only minor biases with intense rainfall events altering supersaturation conditions in the surface waters. Testing the use of calcite rafts in sediment cores from Hoyo Negro show that geochemical analyses (87Sr/86Sr, δ18O, δ13C, Sr/Ca and Cl/Ca) show that meteoric water mass salinity varied during the Holocene (~ 8.5 Ka – present) likely due to changing rainfall and or cave passage geomorphology, which is coherent with other independent climate records. Prior to this study, calcite rafts have never been considered a paleo-hydrological archive for aquifer conditions, however, the consistency and cross-validation with independent records demonstrates great potential for future paleohydrological reconstructions. / Thesis / Doctor of Philosophy (PhD)

The halocline layer plays a crucial role in the Arctic Ocean stratification by separating the sea ice on top of the surface mixed layer (SML) from the heat of the Atlantic Water (AW) below. This is due to the layer’s strong vertical salinity and density gradients, which provide great stability. However, this layer is not as persistent as expected, according to observations (e.g. Steele and Boyd, 1998; Björk et al., 2002; Polyakov et al., 2017). Especially in the context of climate change and Arctic amplification, a continuous description and reliable detection method of the halocline is important. In this thesis different perspectives are used to analyse the Arctic halocline layer. The focus is on the representation and detection of the halocline layer in ocean circulation models and observations. First, the relationship between energy fluxes at the ocean and ice surface and the persistence of the halocline is analysed in an ensemble of 15 ocean circulation models from the Coupled Model Intercomparison Project Phase 5. An increase in the surface energy flux is found in climate projections, which is not locally balanced. This is proposed to be caused partly by a significant decrease in the persistence of the halocline layer found in the models, supporting the idea of “atlantification” described by Polyakov et al. (2018). Various methods have been used to determine the depth of the halocline base. Since the temperature difference method proposed in the author’s master’s thesis and the commonly used density ratio method proposed by Bourgain and Gascard (2011) produce many artefacts, a new method is developed in this thesis. Although the density ratio is more closely related to the definition of the halocline layer, the new method is based on vertical stability as it is strongly associated with the role of the halocline in preventing vertical mixing. Furthermore, the new method is not limited to the inner regions of the Arctic Ocean and it has been successfully used to capture the beginning of a new halocline formation in the western Eurasian Basin.:1 Introduction 2 A models’ view on the Arctic Ocean surface energy flux and the temporal change of the cold halocline 2.1 Introduction 2.2 Materials and methods 2.2.1 Model data 2.2.2 Diagnostics 2.3 Results 2.3.1 Surface Energy Fluxes 2.3.2 Halocline Diagnostics 2.3.3 Spatial distribution of Halocline Thinning Events 2.3.4 Seasonality of Cold Halocline Thinning Events 2.3.5 Correlation with Sea Ice and inflow of Atlantic Water 2.4 Discussion 3 Evaluation of the halocline in the ICON-Ocean model using tracks and Arctic wide maps 3.1 Introduction 3.2 Model, data and methods 3.2.1 Model data from experimental ICON-Ocean model 3.2.2 Observational data 3.2.3 Kriging 3.2.4 Halocline layer diagnostics 3.3 Results 3.3.1 Comparison along ITP-tracks 3.3.2 Influence of model output frequency on estimated halocline properties 3.3.3 Arctic wide comparison 3.4 Discussion 4 A new method for the halocline base depending on vertical stability 4.1 Introduction 4.2 Methods and Data 4.2.1 Methods for estimating the halocline base depth 4.2.2 Cold halostad (CHS) boundary and center estimates 4.2.3 SML depth estimate 4.2.4 Data and preprocessing 4.3 Results 4.3.1 Comparison of methods for deriving halocline base depth using case studies 4.3.2 Statistical comparison of the halocline base depth and occurrence frequency from different methods 4.3.3 Estimation of cold halostad boundaries 4.4 Discussion 5 Trend of the halocline structure in the Arctic ocean from observations 5.1 Introduction 5.2 Methods 5.2.1 Halocline layer boundary depths 5.2.2 Data 5.2.3 Empirical Orthogonal functions of the stability profile 5.2.4 Trend-analysis 5.3 Results 5.3.1 Stability structure within the halocline 5.3.2 EOF coefficient trends 5.3.3 Trends of the SML and halocline base depths 5.4 Discussion 6 Summary and Conclusions Appendices A Appendix A B Appendix B C Appendix C D Appendix D References List of abbreviations and acronyms List of tables List of figures Acknowledgement / Die kalte Halokline spielt eine entscheidende Rolle bei der Schichtung im Arktischen Ozean, indem sie das Meereis oberhalb der gemischten Oberflächenschicht (SML) von der Wärme des Atlantikwassers (AW) darunter trennt. Dies ist auf die starken vertikalen Salzgehalts- und Dichtegradienten der Schicht zurückzuführen, die für große Stabilität sorgen. Allerdings ist diese Schicht nicht so beständig wie erwartet, wie Beobachtungen zeigen (z.B. Steele and Boyd, 1998; Björk et al., 2002; Polyakov et al., 2017). Gerade im Zusammenhang mit dem Klimawandel und der Arktischen Verstärkung (Arctic Amplification) ist eine kontinuierliche Beschreibung und verlässliche Bestimmungsmethode der Halokline wichtig. In dieser Arbeit wurden verschiedene Perspektiven zur Analyse der arktischen Halokline eingenommen. Der Schwerpunkt liegt auf der Repräsentation und Erkennung der Halokline-Schicht in Ozeanzirkulationsmodellen und Beobachtungen. Zunächst wird der Zusammenhang zwischen Energieflüssen an der Ozean-bzw. Eisoberfläche und der Beständigkeit der Halokline in einem Ensemble von 15 Ozeanzirkulationsmodellen aus dem Coupled Model Intercomparison Project Phase 5 untersucht. Dabei wird in den Klimaprojektionen ein Anstieg des Oberflächenenergieflusses festgestellt, der lokal nicht ausgeglichen ist. Es wird angenommen, dass dies zum Teil durch eine signifikante Abnahme der Persistenz der Halokline-Schicht in den Modellen verursacht wird, was die von Polyakov et al. (2018) beschriebene Idee der “Atlantifizierung” unterstützt. Um die Tiefe der Haloklinenunterkante zu bestimmen, wurden mehrere Methoden verwendet. Da die in der Masterarbeit des Autors vorgeschlagene Temperaturdifferenzmethode und die von Bourgain and Gascard (2011) vorgeschlagene, häufig verwendete Dichteverhältnismethode viele Artefakte erzeugen, wird in dieser Arbeit eine neue Methode entwickelt. Obwohl das Dichteverhältnis enger mit der Definition der Haloklinenschicht verbunden ist, basiert die neue Methode auf der vertikalen Stabilität, da sie eng mit der Rolle der Halokline, die vertikalen Durchmischung zu unterdrücken, zusammenhängt. Außerdem ist die neue Methode nicht auf die inneren Regionen des Arktischen Ozeans beschränkt und konnte zudem erfolgreich zur Erfassung des Beginns der Bildung einer neuen Halokline im westlichen Eurasischen Becken eingesetzt werden.:1 Introduction 2 A models’ view on the Arctic Ocean surface energy flux and the temporal change of the cold halocline 2.1 Introduction 2.2 Materials and methods 2.2.1 Model data 2.2.2 Diagnostics 2.3 Results 2.3.1 Surface Energy Fluxes 2.3.2 Halocline Diagnostics 2.3.3 Spatial distribution of Halocline Thinning Events 2.3.4 Seasonality of Cold Halocline Thinning Events 2.3.5 Correlation with Sea Ice and inflow of Atlantic Water 2.4 Discussion 3 Evaluation of the halocline in the ICON-Ocean model using tracks and Arctic wide maps 3.1 Introduction 3.2 Model, data and methods 3.2.1 Model data from experimental ICON-Ocean model 3.2.2 Observational data 3.2.3 Kriging 3.2.4 Halocline layer diagnostics 3.3 Results 3.3.1 Comparison along ITP-tracks 3.3.2 Influence of model output frequency on estimated halocline properties 3.3.3 Arctic wide comparison 3.4 Discussion 4 A new method for the halocline base depending on vertical stability 4.1 Introduction 4.2 Methods and Data 4.2.1 Methods for estimating the halocline base depth 4.2.2 Cold halostad (CHS) boundary and center estimates 4.2.3 SML depth estimate 4.2.4 Data and preprocessing 4.3 Results 4.3.1 Comparison of methods for deriving halocline base depth using case studies 4.3.2 Statistical comparison of the halocline base depth and occurrence frequency from different methods 4.3.3 Estimation of cold halostad boundaries 4.4 Discussion 5 Trend of the halocline structure in the Arctic ocean from observations 5.1 Introduction 5.2 Methods 5.2.1 Halocline layer boundary depths 5.2.2 Data 5.2.3 Empirical Orthogonal functions of the stability profile 5.2.4 Trend-analysis 5.3 Results 5.3.1 Stability structure within the halocline 5.3.2 EOF coefficient trends 5.3.3 Trends of the SML and halocline base depths 5.4 Discussion 6 Summary and Conclusions Appendices A Appendix A B Appendix B C Appendix C D Appendix D References List of abbreviations and acronyms List of tables List of figures Acknowledgement

To counteract one of the most urgent environmental issues in the Baltic Sea; eutrophication, excessivealgal blooms and hypoxia, a proposal to use wave energy to pump oxygen-rich surface water towardsthe sea bottom is investigated. Proposals have suggested that 100 kg of oxygen per second is needed tooxygenate bottom water and enhance binding of phosphorus to bottom sediments. This corresponds to 10 000 m3/s of oxygen-rich surface water. This thesis investigates a wave-powered device to facilitatethis oxygen ux. Results give expected water flow rates between 0.15 - 0.40 m3/s and meter breakwater.The mean specic wave power for the analyzed wave data is calculated to be between 3 - 4 kW/m wavecrest and the median to 1 kW/m. This study indicate, however, that the energy uxes in the BalticProper are signicantly higher. The study gives that the wave climate of the Baltic Sea is suffciently intense to facilitate vertical pumping with a feasible number of breakwaters. A full-scale implementationin the Baltic Sea would require some 300 to 1 200 oating breakwaters of a length of 50 m each. Thetotal cost is roughly estimated to 170 - 680 million EURO. The study also concludes that the interleavingof surface water should be constrained to a relatively small vertical distance from the outlet depth(20 - 30 m) and not stir up deep water to the surface. Wave modelling for the proposed pilot locationKanholmsfjärden indicate that this bay is not large enough to permanently produce a favorable waveclimate. It is, however, still an interesting location consistently to its vicinity to Stockholm and relativelylong measurement series.

Tableau d’honneur de la Faculté des études supérieures et postdoctorales, 2013-2014. / Mon mémoire de maîtrise porte sur la gestion du timbre comme genèse à la composition de trois œuvres originales : 1) Halocline – 11’45’’ – pour flûte, clarinette, percussions, violon, alto et violoncelle; 2) Le mot juste – 9’30’’ – pour orchestre symphonique; 3) Profondeurs de champ – 16’30’’ – pour orchestre de chambre. Après la présentation de mes préoccupations artistiques, des origines et objectifs de mon travail de création, j’expose l’ensemble de mes recherches préliminaires. Finalement, les œuvres sont sommairement analysées de manière à mettre en lumière des modes de gestion du timbre ayant menés à la composition des œuvres. Ceux-ci tirent leurs origines de réflexions sur des concepts génériques du timbre. 1) Halocline : combinaisons de timbres – l’orchestration traditionnelle; 2) Le mot juste : emprunt de la structure du syntagme « le mot juste » pour la gestion du timbre – la phonétique; 3) Profondeurs de champ : catégorisation de timbres – les techniques instrumentales avancées.

Abstract The eutrophication of the Baltic Sea continues despite decrease of the external phosphorus load by as much as 80% of the target confirmed by HELCOM. The aim of this thesis is to investigate this paradox, critically evaluate previous explanations for the persistent eutrophication, and to introduce a new diagnosis and paradigm for the causes and processes behind eutrophication of the Baltic Sea. According to the current consensus, anthropogenic nutrient loading is nearly the sole cause of eutrophication and regular cyanobacterial blooms. However, this study shows that the areal phosphorus loading rate, when modeled properly, is surprisingly low, and unlikely to be the primary cause of eutrophication. Instead, the frequency of the salt water pulses has decreased dramatically during the past 40 years. This is the root cause of eutrophication, via the hyper-vicious cycle of the hypoxic and finally anoxic conditions of the deeps causing internal phosphorus loading, denitrification, and nitrogen and carbon fixation. Furthermore, this work confirms that nitrogen fixation increases in low nitrogen conditions, further increasing eutrophication and cyanobacterial blooms. Thus, the most effective way to break the cycle of eutrophication is to improve the oxygen conditions of the deeps, which really is impossible to achieve by decreasing external loading alone. A key result of this work is that natural processes, rather than human activity, plays a decisive role in the eutrophication process – a perspective that typically faces substantial resistance. This thesis discusses how sociological and political views have affected the scientific community and its pursuit to model the mechanisms of eutrophication of the Baltic Sea. In conclusion, this study leads to important novel insights by providing new models for calculating the external and internal phosphorus loads of the Baltic Sea, with results highlighting the importance of natural processes of internal loading from the anoxic deeps. Altogether, this thesis introduces a new a paradigm for eutrophication of the Baltic Sea. / Tiivistelmä Itämeri rehevöityy edelleen, vaikka fosforikuormitusta on vähennetty 80 % tavoitellusta. On siis syytä tutkia miksi Itämeren tila ei ole parantunut. Syntyneen ristiriidan ratkaisemiseksi tarkoituksena on etsiä aiemmista tulkinnoista ristiriitoja, korjata ne ja uudistaa tietopohja uudeksi ja toimivammaksi paradigmaksi. Virhetulkintojen tunnistamiseen sovelletaan Popperin falsifikaatiomenettelyn periaatteita. Konsensuksen mukaan ihmisperäinen kuormitus on lähes yksinomainen syy (sinilevä)rehevyyteen. Kuitenkin Vollenweiderin mallin mukaan tehty, hydrologialla painotettu fosforin pintakuormitus on ollut 1970 - 1980-luvuilla vain lievää rehevyyttä edellyttävällä tasolla. Ulkoinen kuormitus ei siten voi olla suurin rehevyyden aiheuttaja. Sinilevärehevyyttä ylläpitävänä päätekijänä on syvävesiin happea tuovien suolavesipulssien toistuvuuden romahtaminen. Siitä syntyneet syvävesien ja -pohjien hapettomuudet aiheuttavat Gotlanninmeressä sekä sisäistä kuormitusta että lisärehevöittävää typen- ja hiilensidontaa. Yhdessä näitä prosesseja nimitetään nyt supernoidankehäksi. Johtopäätöksiä: • Ihmistieteelliset ja ympäristöpoliittiset näkemykset vaikuttavat luonnontieteellisiin tulkintoihin luultua enemmän. • Suolavesipulssien harventuminen on hapettomuus- ja rehevyyskierteen perussyy. • Syvänteiden hapettomuus on kaikkialle negatiivisesti säteilevä keskeistekijä. • Itämeren supernoidankehä on purettava saattamalla syvänteet hapellisiksi. • Hapellisuutta ei voida saada aikaan ulkoisen kuormituksen vähentämisellä. • Jäljelle jäävät siten teknologiset keinot, joista toteutuskelvollisimmalta näyttää Itämeren hapellisimman ja kylmimmän veden pumppaus 30 metrin syvyydestä syvänteisiin, mikä tehostaa myös pulssivesien virtausta syvänteiden pohjalle. Tämä väitöskirja sisältää viisi vallitsevasta paradigmasta poikkeavaa tulosta: 1. Itämerelle on kehitetty rehevyyden uusi diagnoosi ja paradigma, 2. Luonto dominoi Itämeren tilaa, ei ihminen, 3. Typensidonnalla on lisärehevöittävä mekanismi, 4. Itämerelle on kehitetty uusi fosforin sisäkuormituksen laskentamenetelmä, 5. Virtuaalisen fosforikuormituksen laskenta. Ilman Gotlanninmeren syvänteiden hapellisuutta Itämeri on tuomittu pysymään rehevyyden supernoidankehässä, ’kaksinkertaisessa takalukossa’.