ALBERT

Description: Deutschlands Klimaschutzstrategie baut auf den Einsatz von grünem Wasserstoff aus erneuerbaren Energien. Doch wo soll der Wasserstoff herkommen, aus heimischer Produktion oder importiert aus dem Ausland? Eine Studie des Wuppertal Instituts und DIW Econ schafft einen Überblick über die aktuelle Datenlage und ermittelt Wertschöpfungs- und Beschäftigungseffekte beider Strategien. Das Resümee: Es trifft nicht zu, dass importierter Wasserstoff allgemein günstiger ist, entscheidend sind je nach Herkunftsland die tatsächlich realisierbaren Strom- und Transportkosten. Wird der grüne Wasserstoff stattdessen im eigenen Land produziert, wird dies zudem eine positive Beschäftigungswirkung und Wertschöpfung entfalten. Mit der Erreichung der Klimaziele 2050 betrüge die zusätzliche Wertschöpfung bei einer stark auf die heimische Erzeugung ausgerichtete Strategie bis zu 30 Milliarden Euro im Jahr 2050 und es könnten bis zu 800.000 Arbeitsplätze geschaffen werden.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Aeronautics and Astronautics at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 2020.

Description: Contemporary scientific exploration most often takes place in highly remote and dangerous environments, such as in the deep sea and on other planets. These environments are very hostile to humans, which makes robotic exploration the first and often the only option. However, they also impose restrictive limits on how much communication is possible, creating challenges in implementing remote command and control. We propose an approach to enable more efficient autonomous robot-based scientific exploration of remote environments despite these limits on human-robot communication. We find this requires the robot to have a spatial observation model that can predict where to find various phenomena, a reward model which can measure how relevant these phenomena are to the scientific mission objectives, and an adaptive path planner which can use this information to plan high scientific value paths. We identified and addressed two main gaps: the lack of a general-purpose means for spatial observation modelling, and the challenge in learning a reward model based on images online given the limited bandwidth constraints. Our first key contribution is enabling general-purpose spatial observation modelling through spatio-temporal topic models, which are well suited for unsupervised scientific exploration of novel environments. Our next key contribution is an active learning criterion which enables learning an image-based reward model during an exploration mission by communicating with the science team efficiently. We show that using these together can result in a robotic explorer collecting up to 230% more scientifically relevant observations in a single mission than when using lawnmower trajectories.

Description: This work was partially supported by the National Science Foundation (NSF) Award #1734400, as well as by the Woods Hole Oceanographic Institution (WHOI). The author would like to thank both organizations for their support.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2020.

Description: A detailed understanding of the intensity and three-dimensional spatial distribution of diabatic abyssal turbulence is germane to understanding the abyssal branch of the global overturning circulation. This thesis addresses the issue through 1) an investigation of the dynamics of an abyssal boundary layer and through 2) the construction of a probabilistic finescale parameterization using mixture density networks (MDNs). A boundary layer, formed by the interaction of heaving isopycnals by the tide and viscous/adiabatic boundary conditions, is investigated through direct numerical simulations (DNS) and Floquet analysis. Turbulence is sustained throughout the tidal period in the DNS on extra-critical slopes characterized by small slope Burger numbers, leading to the formation of turbulent stratified Stokes-Ekman layers. Floquet analysis suggests that the boundary layers are unstable to disturbances to the vorticity component aligned with the across-isobath tidal velocity on extra-critical slopes. MDNs, trained on microstructure observations, are used to construct probabilistic finescale parameterization dependent on the finescale vertical kinetic energy (VKE), N2f2, , and both variables. The MDN model predictions are as accurate as conventional parameterizations, but also predict the underlying probability density function of the dissipation rate as a function of the dependent parameters.

Description: My doctoral studies in the WHOI/MIT Joint Program were funded by the National Science Foundation (OCE-1657870) and the National Science Foundation Graduate Research Fellowship Program.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 2020.

Description: Developing accurate and computationally efficient models for ocean acoustics is inherently challenging due to several factors including the complex physical processes and the need to provide results on a large range of scales. Furthermore, the ocean itself is an inherently dynamic environment within the multiple scales. Even if we could measure the exact properties at a specific instant, the ocean will continue to change in the smallest temporal scales, ever increasing the uncertainty in the ocean prediction. In this work, we explore ocean acoustic prediction from the basics of the wave equation and its derivation. We then explain the deterministic implementations of the Parabolic Equation, Ray Theory, and Level Sets methods for ocean acoustic computation. We investigate methods for evolving stochastic fields using direct Monte Carlo, Empirical Orthogonal Functions, and adaptive Dynamically Orthogonal (DO) differential equations. As we evaluate the potential of Reduced-Order Models for stochastic ocean acoustics prediction, for the first time, we derive and implement the stochastic DO differential equations for Ray Tracing (DO-Ray), starting from the differential equations of Ray theory. With a stochastic DO-Ray implementation, we can start from non-Gaussian environmental uncertainties and compute the stochastic acoustic ray fields in a reduced order fashion, all while preserving the complex statistics of the ocean environment and the nonlinear relations with stochastic ray tracing. We outline a deterministic Ray-Tracing model, validate our implementation, and perform Monte Carlo stochastic computation as a basis for comparison. We then present the stochastic DO-Ray methodology with detailed derivations. We develop varied algorithms and discuss implementation challenges and solutions, using again direct Monte Carlo for comparison. We apply the stochastic DO-Ray methodology to three idealized cases of stochastic sound-speed profiles (SSPs): constant-gradients, uncertain deep-sound channel, and a varied sonic layer depth. Through this implementation with non-Gaussian examples, we observe the ability to represent the stochastic ray trace field in a reduced order fashion.

Description: Office of Naval Research Grants N00014-19-1-2664 (Task Force Ocean: DEEP-AI) and N00014-19-1-2693 (INBDA)

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ferrer-González, F. X., Widner, B., Holderman, N. R., Glushka, J., Edison, A. S., Kujawinski, E. B., & Moran, M. A. Resource partitioning of phytoplankton metabolites that support bacterial heterotrophy. ISME Journal, (2020), doi:10.1038/s41396-020-00811-y.

Description: The communities of bacteria that assemble around marine microphytoplankton are predictably dominated by Rhodobacterales, Flavobacteriales, and families within the Gammaproteobacteria. Yet whether this consistent ecological pattern reflects the result of resource-based niche partitioning or resource competition requires better knowledge of the metabolites linking microbial autotrophs and heterotrophs in the surface ocean. We characterized molecules targeted for uptake by three heterotrophic bacteria individually co-cultured with a marine diatom using two strategies that vetted the exometabolite pool for biological relevance by means of bacterial activity assays: expression of diagnostic genes and net drawdown of exometabolites, the latter detected with mass spectrometry and nuclear magnetic resonance using novel sample preparation approaches. Of the more than 36 organic molecules with evidence of bacterial uptake, 53% contained nitrogen (including nucleosides and amino acids), 11% were organic sulfur compounds (including dihydroxypropanesulfonate and dimethysulfoniopropionate), and 28% were components of polysaccharides (including chrysolaminarin, chitin, and alginate). Overlap in phytoplankton-derived metabolite use by bacteria in the absence of competition was low, and only guanosine, proline, and N-acetyl-d-glucosamine were predicted to be used by all three. Exometabolite uptake pattern points to a key role for ecological resource partitioning in the assembly marine bacterial communities transforming recent photosynthate.

Description: This work was supported by grants from the Gordon and Betty Moore Foundation (5503) and the National Science Foundation (IOS-1656311) to MAM, ASE, and EBK, and by the Simons Foundation grant 542391 to MAM within the Principles of Microbial Ecosystems (PriME) Collaborative.

Description: Any energy efficiency impact evaluation can be done from different analytical perspectives, e.g. the investor/end-user perspective, program administrator perspective or the societal perspective. COMBI applies the "societal perspective", as this is most relevant for policy-making. COMBI draws on a reference scenario until the year 2030 including existing (partially already ambitious) policies. By modelling 21 sets of "energy efficiency improvement" (EEI) actions, a second efficiency scenario was modelled amounting to additional energy savings of around 8% p.a. in 2030, that is comparable to the EUCO+33 to EUCO+35 scenario. This D2.7 quantification report summarises the quantification approaches applied in the COMBI project and main project findings. It therefore draws on other COMBI reports that contain this information in greater detail in order to summarise quantifications. The report is structured in three main sections: 1. The COMBI approach and methods, explaining key methodological approaches both for individual impact quantifications and for the aggregation of impacts 2. Quantification results, giving an overview on main figures of quantified indicators and 3. Insights from cross-impact analysis, which gives a comparison between monetised impacts and presents their use for Cost-Benefit calculations in the COMBI online tool.

Description: Much of the current literature on climate clubs sees mitigation costs creating free rider incentives as the main problem of climate policy. Climate clubs are supposed to solve this problem by creating additional incentives for mitigation. Looking more in detail, one sees that the situation differs from sector to sector. Some industry sectors indeed have substantial cost and competitiveness issues. In others such as electricity and transport, there are costs at micro level but balance for economy and society as a whole is rather positive. International climate policy in general and clubs in particular should therefore be tailored to sectoral specifics.

Description: Der Begriff "Pfand" umfasst in seinen konkreten Anwendungen ganz unterschiedliche Konzepte, die sich mit unterschiedlichen Zielsetzungen auf verschiedene Produktgruppen beziehen und dabei sehr unterschiedliche Effekte auslösen. Zentrales Ziel dieser Kurzstudie ist es, zu einer etwas differenzierteren Betrachtung von Pfandsystemen beizutragen und auf die Stärken und Schwächen in den verschiedenen Anwendungskontexten hinzuweisen. Mit diesem Ziel werden in Kapitel 2 verschiedene Best-Practice-Beispiele dargestellt, bei denen die Einführung von Pfandsystemen in verschiedenen Formen zur Umsetzung einer Kreislaufwirtschaft beigetragen haben. Kapitel 3 beschreibt die verschiedenen Kriterien, auf deren Basis sich unterschiedliche Pfandsysteme für konkrete Produktgruppen begründen lassen könnten; ein spezifischer Fokus wird hierbei auf Verpackungssysteme gelegt. Im abschließenden Kapitel 4 werden davon ausgehend Handlungsempfehlungen entwickelt, wie das Instrument Pfand in Deutschland in möglichst effizienter Form genutzt werden könnte.

Description: The COMBI project aimed at quantifying the multiple non-energy benefits of energy efficiency in the EU-28 area and incorporate those multiple impacts into decision-support frameworks for policy-making. Therefore, all multiple impacts of energy efficiency are analysed from an overall societal view in the project. The COMBI policy recommendations resulting from the evaluation outcomes are presented in this report. COMBI draws on a reference scenario until the year 2030 including existing policies. By modelling 21 sets of "energy efficiency improvement" (EEI) actions, a second efficiency scenario was modelled amounting to additional energy savings of around 8% p.a. in 2030, and that is comparable to the EUCO+33 to EUCO+35 scenario. All figures quantified by COMBI relate to additional values, i.e. additional impacts resulting from additional EEI actions beyond the reference scenario as a consequence of additional policies. The project quantified in total 31 individual impact indicators with appropriate state-of-the-art models.

Description: The Wuppertal Institute conducted an impact analysis of the NRW Sustainability Bond #4 of 2018 on behalf of the State Government of North Rhine-Westphalia (NRW). The most recent bond has a volume of EUR 2.025bn, a term of 10 years and consists of 52 eligible projects from the State's 2017 general budget (sustainable value-added was confirmed in a second party opinion by oekom research1). This report analyses the contribution of the bond to climate mitigation, sustainable land use and social impacts. It also includes information on the impacts of the previous three bonds (NRW Sustainability Bond #1 to #3).

Description: Innerhalb des Projekts TFE-NRW bewertete das Wuppertal Institut den Forschungsbedarf für Energiewende-Technologien in Nordrhein-Westfalen. Ziel war es herauszufinden, welche Technologien und Forschungsbereiche im Rahmen der Energieforschung für Nordrhein-Westfalen (NRW) einen besonders hohen Stellenwert in Relation zur Bewertung für Deutschland haben könnten und für die eine besondere Unterstützung innerhalb der Energieforschung gerechtfertigt erscheint. Dabei sollten die speziellen Anforderungen des Bundeslandes berücksichtigt werden. Betrachtet wurden 31 Technologiefelder aus den Bereichen erneuerbare Energien, konventionelle Kraftwerke, Infrastruktur, Technologien für die Sektorenkopplung (Power-to-X, P2X), energie- und ressourceneffiziente Gebäude, Energie- und Ressourceneffizienz in der Industrie und integrative Aspekte, die mithilfe eines Kriterienrasters qualitativ bewertet wurden.

Description: Die GLS Bank finanziert gezielt nachhaltige Projekte und Unternehmen in den Bereichen erneuerbare Energien, nachhaltige Wirtschaft, Ernährung, Wohnen, Bildung & Kultur, Soziales & Gesundheit. Eine zentrale Herausforderung ist es, die Nachhaltigkeitswirkung der Finanz- und Anlagestrategie robust zu quantifizieren und transparent darzustellen. Die GLS Bank hat sich zum Ziel gesetzt, die hierfür notwendigen Methoden und Daten zur Bewertung der Nachhaltigkeitswirkungen ihres Finanz- und Anlagenportfolios schrittweise weiterzuentwickeln, um eine richtungssichere Portfoliosteuerung und Kundenbetreuung zu unterstützen. Ziel des Projektes ist zunächst, das Emissionsgeschehen der finanzierten Wertschöpfungskette abzubilden (Scope 3), aber auch die eingesparten Emissionen als einen Beitrag zum Klimaschutz zu bewerten (Scope 4). Es werden die Scope 3 Emissionen der GLS Bank in den folgenden Finanz- und Anlagebereichen für das Berichtsjahr 2019 bilanziert: 1. Aktien- und Klimafonds; 2. Kredite; 3. Unternehmensbeteiligung. Scope 4 Emissionen werden in Form vermiedener Emissionen (Carbon Handprint) dabei ausschließlich für Bereiche bilanziert, in denen THG-Reduktionspotentiale richtungssicher abgeschätzt werden können. Im vorliegenden Bericht wird der Untersuchungsrahmen, die vom Wuppertal Institut entwickelte Methodik sowie Lösungsstrategien für die Überbrückung geringer Datenqualität/-verfügbarkeit beschrieben. Die Robustheit der Ergebnisse wird durch Prüfungsmethoden reflektiert und dem Leser somit eine Interpretationsunterstützung gegeben. In einem Ausblick werden Weiterentwicklungsbedarfe und -möglichkeiten skizziert, um schrittweise eine zunehmend robuste und wissenschaftliche fundierte Methodik und Datengrundlage zur Bewertung der Klimawirkung sowie weiterer Nachhaltigkeitswirkungen des Finanz- und Anlageportfolios der GLS Bank in Zusammenarbeit mit relevanten Stakeholdern zu etablieren.

Description: The Wuppertal Institute conducted an impact analysis of the NRW sustainability bond #5 of 2019 on behalf of the State government of North Rhine-Westphalia (NRW). The most recent bond has a volume of EUR 2.25 bn, a term of 15 years and consists of 52 eligible projects from the State's 2018 general budget (sustainable value-added was confirmed in a second party opinion by ISS-oekom). This report analyses the contribution of the bond to climate mitigation, sustainable land use and social impacts. It also includes information on the impacts of the previous four bonds (NRW sustainability bond #1 to #4).

Description: Ziel der vorliegenden Studie ist es, positive Nachhaltigkeitseffekte für die in 2017 emittierte Nachhaltigskeitsanleihe NRW zu bewerten. Die Studie baut dabei auf der Wirkungsanalyse der zweiten Nachhaltigskeitsanleihe NRW auf. Diese Studie war auf die Abschätzung von Treibhausgas-Minderungspotenzialen (THG-Minderungen) fokussiert. Der Fokus der vorliegenden Studie liegt ebenfalls auf der Evaluation der potenziellen THG-Minderung, da deren Bewertung sich derzeit als Standard für eine Wirkungsanalyse solcher Anleihen abzeichnet.

Description: Die Digitalisierung und der demografische Wandel sind Megatrends, die die Energiewende überlagern. Mehr denn je sind daher integrierte Problemlösungskonzepte für die Umsetzung der Energiewende gefragt. Neben den technischen Aspekten sollen diese Lösungen auf die sozio-ökonomischen Charakteristika der einzelnen Regionen und Kommunen eingehen und mögliche Veränderungen durch die Megatrends berücksichtigen. Zielsetzung des Teilprojekts war die Entwicklung eines wirtschaftlich-, ökologisch- und sozial optimalen Wärmeversorgungskonzepts für die Konversionsfläche der ehemaligen Zeche Westerholt in Gelsenkirchen-Herten. Im Fokus stand das Gesamtsystem der Wärmeversorgung, bestehend aus Netz, Speicher und Erzeugung. Angestrebt wurde eine zukunftsfähige Niedertemperaturversorgung (LowEx), welche Technologien der Sektorkopplung und diverse erneuerbare Energiequellen wie Solarthermie, Erdwärme und Abwärmequellen einbinden kann. Dabei wurde eine integrierte Analyse technisch-infrastruktureller sowie sozio-ökonomischer und -kultureller Umsetzungsvoraussetzungen durchgeführt. Neben der interkommunalen Einbindung zeichnete sich das Vorhaben durch ein transdisziplinäres Projektkonsortium aus Kommune, Stadtwerk, Wissenschaft, Technologieentwicklern und Planungsbüros aus.

Description: Of all the socio-economic changes caused by the Covid-19 pandemic, the disruption to workforce organizations will probably leave the largest indelible mark. The way work will be organized in the future will be closely linked to the experience of work-ing under the same institution’s response to the pandemic. This paper aims to fill the gap in knowledge about smart working (SW) in public organizations, with a focus on the experience of the employees of two Italian research organizations, CNR and INGV. Analysing primary data, it explored and assessed how SW had been experi-enced following the implementation of governmental measures aimed at limiting the spread of COVID-19

Description: Published

Description: 815–833

Description: 2TM. Divulgazione Scientifica

Description: JCR Journal

Description: Data visualization, and to a lesser extent data sonification, are classic tools to the scientific community. However, these two approaches are very rarely combined, although they are highly complementary: our visual system is good at recognizing spatial patterns, whereas our auditory system is better tuned for temporal patterns. In this article, data representation methods are proposed that combine visualization, sonification, and spatial audio techniques, in order to optimize the user’s perception of spatial and temporal patterns in a single display, to increase the feeling of immersion, and to take advantage of multimodal integration mechanisms. Three seismic data sets are used to illustrate the methods, covering different physical phenomena, time scales, spatial distributions, and spatio-temporal dynamics. The methods are adapted to the specificities of each data set, and to the amount of information that the designer wants to display. This leads to further developments, namely the use of audification with two time scales, the switch from pure audification to time-modulated noise, and the switch from pure audification to sonic icons. First user feedback from live demonstrations indicates that the methods presented in this article seem to enhance the perception of spatio-temporal patterns, which is a key parameter to the understanding of seismically active systems, and a step towards apprehending the processes that drive this activity.

Description: Published

Description: 125–142

Description: 7T. Variazioni delle caratteristiche crostali e "precursori"

Description: JCR Journal

Description: Die vorangegangenen Analysen im RESTORE2050 Projekt, die im Rahmen dieses Berichts weitergeführt werden, haben gezeigt, dass der Einsatz von Wasserstoffspeichern zur Residuallastglättung nur bedingt geeignet ist. Zwar bietet die Technologie ein hohes technisches Potenzial hinsichtlich der Speicherkapazitäten und der installierbaren elektrischen Leistungen. Jedoch führt ein systemdienlicher Einsatz, bei dem positive Residuallastspitzen u. a. durch Anheben geringer Residuallasten gesenkt werden, wie er in den Modellrechnungen des RESTORE2050 Projektes implementiert ist, zu einer Absenkung der Deckungsraten von erneuerbaren Energien (EE) im europäischen Stromsystem. Dies ist dadurch begründet, dass die Umwandlung und Speicherung von EE-Strom als Wasserstoff (H2) im Vergleich zu anderen Speichertechnologien hohe Wandlungsverluste sowohl bei der H2-Erzeugung als auch bei der Rückverstromung aufweisen. Daher wird im Rahmen dieses Aufstockungsprojektes (RESTORE2050_plus) untersucht, welchen Beitrag alternative Einsatzstrategien der H2-Speicher zur Minimierung der negativen Residuallast, also potenzielle erneuerbaren Stromüberschüssen, und gleichzeitig zur Erhöhung der EE- Versorgungsanteile leisten kann.

Description: Das übergeordnete Ziel des Forschungs-Projektes RESTORE 2050 (Regenerative Stromversorgung & Speicherbedarf in 2050; Förderkennzeichen 03SF0439) war es, wissenschaftlich belastbare Handlungsempfehlungen für die Transformation des deutschen Stromsystems im europäischen Kontext zu geben. Dafür wurden auf Basis der zukünftig prognostizierten Entwicklung von Stromangebot und -nachfrage innerhalb des ENTSO-E Netzverbundes für den Zeithorizont des Jahres 2050 sowie mittels örtlich und zeitlich hoch aufgelöster meteorologischer Zeitreihen die Themenkomplexe (1) Nationale Ausbaustrategien für erneuerbare Energien, (2) Übertragungsnetzausbau und (3) Alternativmaßnahmen wie Lastmanagement, (4) Bedeutung des EE-Stromaustauschs mit Drittstaaten und (5) die Rolle von Stromspeichern auf Übertragungsnetzebene analysiert. Die aus den Untersuchungsergebnissen abgeleitenden Handlungsempfehlungen stellen wichtige Beiträge für die weitere Integration von erneuerbaren Energien dar und geben Hinweise für den Aufbau einer leistungsfähigen europäischen Infrastruktur.

Description: Das Konzept der "Wirtschaftsförderung 4.0" (Wf4.0) zielt darauf ab, die lokalen und regionalen Wirtschaftsstrukturen zu stärken. Wf4.0 initiert neue Wertschöpfung vor Ort, eröffnet lokale Investitionsmöglichkeiten, bindet regionale Kaufkraft, entfalten neue Wirtschaftsideen und stärkt lokale Vielfalt. Sie stärkt die Tauschwirtschaft für Ressourcen, Produkte oder Räume und fördert den Gemeinsinn. Mithin erhöht Wf4.0 die Widerstandsfähigkeit gegenüber globalen Wirtschaftskrisen. Wirtschaftsförderung 4.0 wirkt sich damit positiv aus auf den Stadtwohlstand und erhöht die Attraktivität für eine Stadt der kurzen Wege, der Diversität und des guten Lebens. Zugleich erhöht eine Stabilisierung der regionalen und lokalen Wirtschaft die Widerstandsfähigkeit der lokalen Ebene gegen weltweite Krisen. Die "Wirtschaftsförderung 4.0" ergänzt die klassischen Strategien der etablierten Wirtschaftsförderung. Nach und nach hat sich das Handlungsspektrum um die Bereiche Bestandspflege, Clustermanagement und Kreativwirtschaft erweitert. Zahlreiche Maßnahmen der Wf4.0 sind hier bereits verankert. So etwa die Förderung von Nachhaltigen Unternehmen. In dem Projekt wurde untersucht, inwiefern sich der gegenwärtige Leistungskatalog der Wirtschaftsförderung sinnvoll erweitern lässt.

Description: Diese Kurzstudie beschäftigt sich mit der Frage, ob durch den Einsatz von Augmented Reality Anwendungen die Wiederaufbereitung (genauer das Refurbishment) von Produkten gesteigert werden kann. Gleichzeitig betrachtet sie, ob damit auch die Inklusion- und Re-Integration von Schwerbehinderten und langzeitarbeitslosen Menschen in den ersten Arbeitsmarkt unterstützt wird.

Description: Mit dem Ziel, das Kunststoffrecycling weiter zu steigern, wurden in diesem Vorhaben die Verfahren und Prozesse der werkstofflichen Verwertung von Kunststoffabfällen in den Blick genommen - von der Sortierung über die Aufbereitung bis hin zu einem erneuten Einsatz in der Produktion. Ausgehend von der Beschreibung des Standes der Technik wurden mögliche, innovative technische Optimierungspotenziale identifiziert und dargestellt, die zur Verbesserung der Rezyklatqualitäten und ihren Einsatzmöglichkeiten in Neuprodukten beitragen können. Für eine Bewertung der Umweltwirkungen der technischen Innovationen im Vergleich zum Stand wurden ökobilanzielle Berechnungen vorgenommen.

Description: Diese Kurzstudie ist Teil des Verbundvorhabens "Circular Economy als Innovationsmotor für eine klimaneutrale und ressourceneffiziente Wirtschaft (CEWI)" der Stiftung 2°, dem WWF Deutschland und dem Wuppertal Institut und hat zum Ziel, die Potenziale des Gebäudesektors und der dazugehörigen Wertschöpfung im Hinblick auf die Umsetzung von zirkulären Ansätzen zu analysieren und den Beitrag zur Ressourceneinsparung und dem Klimaschutz zu bewerten. Das Ergebnis dieser Kurzstudie leitet sich aus einem intensiven Bewertungsprozess verschiedener Maßnahmen-Cluster ab und besteht aus sechs Handlungsfeldern, die ein Potenzial für den Ausbau von Klimaneutralität und Ressourceneffizienz im Gebäudesektor aufweisen. Diese Handlungsfelder bilden die Grundlage für den weiteren Projektverlauf von CEWI, in dem Industrieakteure in Workshops gemeinsam Pilotprojekte modellieren werden.

Description: Diese Kurzstudie ist Teil des Verbundvorhabens "Circular Economy als Innovationsmotor für eine klimaneutrale und ressourceneffiziente Wirtschaft (CEWI)" der Stiftung 2°, dem WWF Deutschland und dem Wuppertal Institut und hat zum Ziel, die Potenziale des Automobilsektors und der dazugehörigen Wertschöpfung im Hinblick auf die Umsetzung von zirkulären Ansätzen zu analysieren und den Beitrag zur Ressourceneinsparung und dem Klimaschutz zu bewerten. Das Ergebnis dieser Kurzstudie leitet sich aus einem intensiven Bewertungsprozess verschiedener Maßnahmen-Cluster ab und besteht aus sechs Handlungsfeldern, die ein Potenzial für den Ausbau von Klimaneutralität und Ressourceneffizienz im Automobilsektor aufweisen. Diese Handlungsfelder bilden die Grundlage für den weiteren Projektverlauf von CEWI, in dem Akteure aus der Praxis in Workshops gemeinsam Pilotprojekte modellieren werden.

Description: Die Wirtschaftsförderung Region Stuttgart GmbH (WRS) unterstützt die Transformation der Region Stuttgart in Richtung Nachhaltigkeit und sieht die Bioökonomie als eine wichtige Strategie zu diesem Zweck. Die WRS hat das Wuppertal Institut mit dieser Kurzstudie mit dem Fokus auf die industrielle Bioökonomie beauftragt, um eine Informationsgrundlage für die Spezifikation weiterer Aktivitäten der WRS im Kontext der Bioökonomie zu schaffen. Die Studie gibt einen Überblick über definitorische Ansätze und Diskurslinien der Bioökonomie. Sie fasst Einschätzungen des deutschen Bioökonomierates zu Marktpotenzialen der Bioökonomie in verschiedenen Branchen zusammen, die u.a. für Automobil, Biotechnologie und IKT als gut eingeschätzt werden. Anschließend umreißt die Studie die Innovationsansätze Biomimikry und Biointelligenz. Für den Ansatz Biointelligenz zur biologischen Transformation der industriellen Wertschöpfung werden die in Studien von Dritten identifizierten Marktpotenziale der Biointelligenz zusammengefasst, u.a. in den Bereichen Unterstützungssysteme, Produktionssysteme/-technologien und Baumaterialien. Darüber hinaus stellt die Studie Schnittstellen relevanter Landesstrategien in Baden-Württemberg zu Bioökonomiethemen dar, die synergetisch genutzt werden könnten. Ergänzend gibt die Studie einen Überblick über die Akteurslandschaft in Baden-Württemberg. Der Überblick basiert insbesondere auf dem Bioökonomie Kompetenzatlas wissenschaftlicher Akteure, der von der Landeskoordinierungsstelle an der Universität Hohenheim herausgegeben wird, sowie einer Akteursanalyse aus dem Projekt "Bioökonomie in Baden-Württemberg", das am KIT durch das ITAS durchgeführt wurde und durch die BIOPRO Baden-Württemberg GmbH unterstützt wurde. Auf Basis dieser Informationssammlung entwirft die Studie weiterführende Fragen in Bezug auf mögliche weitere Aktivitäten der WRS im Kontext der Bioökonomie, u.a. die mögliche Nutzung von Innovationsansätzen aus dem Bereich der Living Lab und Reallaborforschung.

Description: Diese Kurzstudie beschäftigt sich mit der Frage, ob durch den Einsatz von Augmented Reality Anwendungen die Wiederaufbereitung (genauer das Refurbishment) von Produkten gesteigert werden kann. Gleichzeitig betrachtet sie, ob damit auch die Inklusion- und Re-Integration von Schwerbehinderten und langzeitarbeitslosen Menschen in den ersten Arbeitsmarkt unterstützt wird.

Description: Two thirds of today's world trade is based on global value chains and supply networks. Purely regional supply chains have become less important in recent decades. The effects of these globalised structures are manifold. On the one hand, they promote employment and generate prosperity. On the other hand, they are beset by extreme social, ecological and economic imbalances. The COVID-19 pandemic has demonstrated the fragility of existing supply chain systems. The lockdown continues to disrupt complex supply chains and many problems of existing production and consumption continue to worsen. COVID-19 is one example of the crises that can shake globally networked supply chains in the short term. Other crises, such as climate change, develop more insidiously and are less immediately recognisable. Different as they are, such crises have one thing in common: they highlight the vulnerability of global social and economic structures and illustrate the impact of global trade on the regions and people of the world. This is precisely where global sustainability strategy comes in - it aims to fundamentally reduce differences and inequalities in opportunities and quality of life. The COVID-19 pandemic has forced the entire world into upheaval, creating an opportunity to make sustainability a central political resilience strategy. In the wake of the Corona pandemic, the discussion about resilient communities has flared up. In order to guarantee supply in the face of such crises, these should be more strongly regional and circular in their economic approach and global and sustainable in their perspective. The aim should be sustainable, transparent, non-exploitative supply chains that guarantee the security of supply to cover basic needs and public services despite sudden changes and crises. This discussion paper draws a future scenario of globally cooperative, circular regional economies that fundamentally reduce global inequalities in opportunities and quality of life, while at the same time permanently preserving the natural foundations of life.

Description: Short-term earthquake clustering properties in the Eastern Aegean Sea (Greece) area investigated through the application of an epidemic type stochastic model (Epidemic Type Earthquake Sequence; ETES). The computations are performed in an earthquake catalog covering the period 2008 to 2020 and including 2332 events with a completeness threshold of Mc = 3.1 and separated into two subcatalogs. The first subcatalog is employed for the learning period, which is between 2008/01/01 and 2016/12/31 (N = 1197 earthquakes), and used for the model’s parameters estimation. The second subcatalog from 2017/01/01 to 2020/11/10 (1135 earthquakes), in which the sequences of 2017 Mw = 6.4 Lesvos, 2017 Mw = 6.6 Kos and 2020 Mw = 7.0 Samos main shocks are included, and used for a retrospective forecast testing based on the constructed model. The estimated model parameters imply a swarm like behavior, indicating the ability of earthquakes of small to moderate magnitude above Mc to produce their own offsprings, along with the stronger earthquakes. The retrospective evaluation of the model is examined in the three aftershock sequences, where lack of foreshocks resulted in low predictability of the mainshocks, with estimated daily probabilities around 10– 5. Immediately after the mainshocks occurrence the model adjusts with notable resemblance between the expected and observed aftershock rates, particularly for earthquakes with M ≥ 3.5.

Description: Published

Description: 1085–1099

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: This work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Description: Published

Description: 3287–3315

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: Probabilistic earthquake locations provide confidence intervals for the hypocentre solutions such as errors encountered in the position, the origin time, and in magnitude. If the relationship of the parameters relative to the local arrangement of the seismic network is considered, such as the node distance, the number of stations, the seismic gap, and the quality of phase readings), the uncertainties can then provide insights on the location capability of the network. In this paper, we collect the earthquake data recorded from the Italian Seismic Network for a time span of 5 years. The data pertain to three different catalogues according to the progressive refinement phases of the location procedure: automatic location, revised location, and published location. By means of spatial analysis,we assess the distribution of the location-related and network-related estimators across the study area. These estimators are subsequently combined to assess the existence of spatial correlations at a local scale. The results indicate that the Italian network is generally able to provide robust locations at the national scale and for smaller earthquakes, and the elongated shape of Italy (and of its network) does not cause systematic bias in the locations. However, we highlight the existence of subregions in which the performance of the network is weaker. At present, a unique 2D, 3-layer velocity model is used for the earthquake location procedure, and this could represent the main limitation for the improvement of the locations. Therefore, the assessment of locally optimized velocity models is the priority for the homogenization and the improvement of the Italian Seismic Network performance.

Description: Published

Description: 1061–1076

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: JCR Journal

Description: This paper provides a new contribution to the construction of the complex and fragmentary mosaic of the Late Holocene earthquakes history of the İznik segment of the central strand of the North Anatolian Fault (CNAF) in Turkey. The CNAF clearly displays lower dextral slip rates with respect to the northern strand however, surface rupturing and large damaging earthquakes (M 〉 7) occurred in the past, leaving clear signatures in the built and natural environments. The association of these historical events to specific earthquake sources (e.g., Gemlik, İznik, or Geyve fault segments) is still a matter of debate. We excavated two trenches across the İznik fault trace near Mustafali, a village about 10 km WSW of İznik where the morphological fault scarp was visible although modified by agricultural activities. Radiocarbon and TL dating on samples collected from the trenches show that the displaced deposits are very recent and span the past 2 millennia at most. Evidence for four surface faulting events was found in the Mustafali trenches. The integration of these results with historical data and previous paleoseismological data yields an updated Late Holocene history of surface-rupturing earthquakes along the İznik Fault in 1855, 740 (715), 362, and 121 CE. Evidence for the large M7 + historical earthquake dated 1419 CE generally attributed to this fault, was not found at any trench site along the İznik fault nor in the subaqueous record. This unfit between paleoseismological, stratigraphic, and historical data highlights one more time the urge for extensive paleoseismological trenching and offshore campaigns because of the high potential to solve the uncertainties on the seismogenic history (age, earthquake location, extent of the rupture and size) of this portion of NAFZ and especially on the attribution of historical earthquakes to the causative fault.

Description: Published

Description: 115–128

Description: 2T. Deformazione crostale attiva

Description: N/A or not JCR

Description: In this paper the site categorization criteria and the corresponding site amplification factors proposed in the 2021 draft of Part 1 of Eurocode 8 (2021-draft, CEN/TC250/SC8 Working Draft N1017) are first introduced and compared with the current version of Eurocode 8, as well as with site amplification factors from recent empirical ground motion prediction equations. Afterwards, these values are checked by two approaches. First, a wide dataset of strong motion records is built, where recording stations are classified according to 2021-draft, and the spectral amplifications are empirically estimated computing the site-to-site residuals from regional and global ground motion models for reference rock conditions. Second, a comprehensive parametric numerical study of one-dimensional (1D) site amplification is carried out, based on randomly generated shear-wave velocity profiles, classified according to the new criteria. A reasonably good agreement is found by both approaches. The most relevant discrepancies occur for the shallow soft soil conditions (soil category E) that, owing to the complex interaction of shear wave velocity, soil deposit thickness and frequency range of the excitation, show the largest scatter both in terms of records and of 1D numerical simulations. Furthermore, 1D numerical simulations for soft soil conditions tend to provide lower site amplification factors than 2021-draft, as well as lower than the corresponding site-to-site residuals from records, because of higher impact of non-linear (NL) site effects in the simulations. A site-specific study on NL effects at three KiK-net stations with a significantly large amount of high-intensity recorded ground motions gives support to the 2021-draft NL reduction factors, although the very limited number of recording stations allowing such analysis prevents deriving more general implications. In the presence of such controversial arguments, it is reasonable that a standard should adopt a prudent solution, with a limited reduction of the site amplification factors to account for NL soil response, while leaving the possibility to carry out site-specific estimations of such factors when sufficient information is available to model the ground strain dependency of local soil properties.

Description: Published

Description: 4199–4234

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: ShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.

Description: Published

Description: 5391–5414

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: Analyzing seismic data to get information about earthquakes has always been a major task for seismologists and, more in general, for geophysicists. Recently, thanks to the technological development of observation systems, more and more data are available to perform such tasks. However, this data “grow up” makes “human possibility” of data processing more complex in terms of required efforts and time demanding. That is why new technological approaches such as artificial intelligence are becoming very popular and more and more exploited. In this paper, we explore the possibility of interpreting seismic waveform segments by means of pre-trained deep learning. More specifically, we apply convolutional networks to seismological waveforms recorded at local or regional distances without any pre-elaboration or filtering. We show that such an approach can be very successful in determining if an earthquake is “included” in the seismic wave image and in estimating the distance between the earthquake epicenter and the recording station.

Description: Published

Description: 1347–1359

Description: 1T. Struttura della Terra

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: Themain climatological features of the ionospheric equivalent slab thickness (τ ) for the Northern hemispheremidlatitudes are analyzed. F2-layer peak electron density values recorded at three midlatitude ionospheric stations (Chilton 51.5° N, 0.6° W, U.K.; Roquetes 40.8° N, 0.5° E, Spain;Wallops Island 37.9° N, 75.5°W, USA) and vertical total electron content values from colocated ground-based Global Navigation Satellite System receivers are used to calculate a dataset of τ values for the last two solar cycles, considering only magnetically quiet periods. Results are presented both as grids of binned medians and as boxplots as a function of local time and month of the year, for different solar activity levels. Corresponding trends are first compared to those output by the midlatitude empirical model developed by Fox et al. (Radio Sci 26:429–438, 1991) and then discussed in the light of what is known so far. From this investigation, the strong need to implement an improved empirical model of τ has emerged. Both Space Weather and Space Geodesy applications might benefit from such model. Therefore, both the dataset and the methodology described in the paper represent a first fundamental step aimed at implementing an empirical climatological model of the ionospheric equivalent slab thickness. The study highlighted also that at midlatitudes τ shows the following main patterns: daytime values considerably smaller than nighttime ones (except in summer); well-defined maxima at solar terminator hours; a greater dispersion during nighttime and solar terminator hours; no clear and evident solar activity dependence.

Description: Published

Description: 124

Description: 2A. Fisica dell'alta atmosfera

Description: JCR Journal

Description: The eruption of basaltic magmas dominates explosive volcanism on Earth and other planets within the Solar System. The mechanism through which continuous magma fragments into volcanic particles is central in governing eruption dynamics and the ensuing hazards. However, the mechanism of fragmentation of basaltic magmas is still disputed, with both viscous and brittle mechanisms having been proposed. Here we carry out textural analysis of the products of ten eruptions from seven volcanoes by scanning electron microscopy. We find broken crystals surrounded by intact glass that testify to the brittle fragmentation of basaltic magmas during explosive activity worldwide. We then replicated the natural textures of broken crystals in laboratory experiments where variably crystallized basaltic melt was fragmented by rapid deformation. The experiments reveal that crystals are broken by the propagation of a network of fractures through magma, and that afterwards the fractures heal by viscous flow of the melt. Fracturing and healing affect gas mobility, stress distribution, and bubble and crystal size distributions in magma. Our results challenge the idea that the grain size distribution of basaltic eruption products reflects the density of fractures that initially fragmented the magma and ultimately indicate that brittle fracturing and viscous healing of magma may underlie basaltic explosive eruptions globally.

Description: Published

Description: 248–254

Description: 4V. Processi pre-eruttivi

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: This book serves as a guide to discovering the most interesting volcano sites in Italy. Accompanied by some extraordinary contemporary images of active Neapolitan volcanoes, it explains the main volcanic processes that have been shaping the landscape of the Campania region and influencing human settlements in this area since Greek and Roman times and that have prompted leading international scientists to visit and study this natural volcanology laboratory. While volcanology is the central topic, the book also addresses other aspects related to the area’s volcanism and is divided into three sections: 1) Neapolitan volcanic activity and processes (with a general introduction to volcanology and its development around Naples together with descriptions of the landscape and the main sites worth visiting); 2) Volcanoes and their interactions with local human settlements since the Bronze Age, recent population growth and the transformation of the territory; 3) The risks posed by Neapolitan Volcanoes, their recent activity and the problem of forecasting any future eruption.

Description: Published

Description: 2TM. Divulgazione Scientifica

Description: Die Europäische Union (EU) hat erkannt, dass das Ziel der Klimaneutralität bis 2050 ein zentraler Innovations- und Wachstumsmotor für Industrie und Wirtschaft in der EU sein kann. Neben großen Chancen stellt dies die europäische Wirtschaft und überwiegend die besonders emissionsintensiven sowie im international starkem Wettbewerb stehenden Grundstoffindustrien auch vor erhebliche Herausforderungen. Eine integrierte Klima- und Industriestrategie ist für den Klimaschutz von zentraler Bedeutung, da auf die Produktion von Stahl, Zement, Grundstoffchemikalien, Glas, Papier und anderen Materialien in der EU und weltweit rund 20 Prozent der gesamten Treibhausgasemissionen entfallen. Auch in einer treibhausgasneutralen Zukunft kann auf diese Materialien nicht verzichten werden. Zugleich ist die emissionsfreie Herstellung der Materialien technologisch sowie mit Blick auf die dafür erforderlichen Infrastrukturen besonders herausfordernd. Dies gilt vor allem für die Frage woher die hohen benötigten Mengen an grüner Energie - insbesondere Strom und Wasserstoff - zu wettbewerbsfähigen Preisen kommen sollen. Analysen zeigen, dass trotz erheblicher Kosten bei der Prozessumstellung die Kosten der Transformation der Grundstoffindustrie für die Gesellschaft insgesamt tragbar sind. Denn bezogen auf die Endprodukte betragen die Mehrkosten meist nur wenige Prozentpunkte; die Preise von Rohstahl oder Zement dagegen würden sich zwischen einem Drittel und 100 Prozent verteuern. Da fast alle Grundstoffhersteller in starker Weltmarktkonkurrenz stehen, können sie die Investitionen in eine klimaneutrale Produktion und die benötigten Energieinfrastrukturen aber nicht ohne Unterstützung tragen. Das vorliegende Papier skizziert ein integriertes Klima-Industriepolitikpaket, das der EU ermöglichen kann, die bestehende technologische Führung in vielen dieser Industrien zielgerichtet zum Aufbau einer treibhausgasneutralen Grundstoffindustrie zu nutzen.

Description: Städte und Kommunen mussten in den vergangenen Jahren einiges aushalten: eine weltweite Corona-Pandemie, Feuerkatastrophen wie in den USA sowie Hochwasser-Katastrophen wie in Deutschland. Das sind auch Folgen des menschen-gemachten Klimawandels, auf die Städte sich in Zukunft besser vorbereiten müssen. Denn gerade die Hochwasser-Katastrophe im Juli 2021 hat gezeigt, wie wenig Kommunen auf solche Ereignisse eingerichtet sind. Dieses Impulspapier zeigt, wie Städte resilienter, nachhaltiger und zukunftsfähiger werden können.

Description: Zwei Drittel des heutigen Welthandels gründen auf globalen Wertschöpfungsketten und Versorgungsnetzen. Rein regionalwirtschaftlich organisierte Lieferketten haben in den letzten Jahrzehnten an Bedeutung verloren. Die Auswirkungen dieser globalisierten Strukturen sind vielfältig: Zum einen haben sie beschäftigungsfördernde Effekte und wirken wohlstandsstiftend. Zum anderen existieren entlang der Lieferketten extreme soziale, ökologische und ökonomische Schieflagen. Die COVID-19-Pandemie zeigt in erheblichem Maße, wie fragil bestehende Lieferkettensysteme sind. Der Lockdown unterbricht noch immer komplexe Lieferketten und viele Probleme der bestehenden Produktions- und Konsumweise verschärfen sich weiterhin. COVID-19 ist ein Beispiel einer der möglichen Krisen, welche die globalen und vernetzten Wertschöpfungsketten kurzfristig erschüttern kann. Andere Krisen entwickeln sich schleichender und damit weniger schnell erkennbar, wie etwa der globale Klimawandel. So unterschiedlich sie sind, haben die Krisen eines gemein: Sie zeigen die Verletzlichkeit globaler Gesellschafts- und Wirtschaftsstrukturen auf und verdeutlichen die Wirkungen globalen Handels auf die Regionen und Menschen der Welt. Die globale Nachhaltigkeitsstrategie setzt genau hier an - sie zielt darauf ab, Unterschiede und Ungleichheit in Chancen und Lebensqualität grundlegend zu vermindern. Deshalb sollte die Umsetzung der Nachhaltigkeitsziele auf internationaler, nationaler und regionaler Ebene eine Antwort auf solche Krisen sein. Da durch die Covid-19-Pandemie zeitgleich die komplette Welt in eine Umbruchsituation gedrängt wurde, bietet die Reaktion darauf an, Nachhaltigkeit als zentrale politische Resilienz-Strategie zu nutzen. Im Zuge der Corona-Pandemie flammte die Diskussion um resiliente Kommunen auf. Diese sollten sich stärker an regional- und kreislaufwirtschaftlichen Ansätzen orientieren, um angesichts solcher Pandemien die Versorgung weiterhin gewährleisten zu können. So wichtig und richtig die Entwicklung eigener regionalwirtschaftlicher und kreislauforientierter Ansätze im Kern ist, so wenig resilient ist es, wenn deren Entwicklung nicht unter globaler und nachhaltiger Perspektive erfolgt. Ziel sollten menschengerechte, nachhaltige und transparente Lieferketten sein, die auch bei plötzlich veränderten Rahmenbedingungen und Krisen richtungssicher die Versorgungssicherheit zur Deckung von Grundbedürfnissen und Daseinsvorsorge sicherstellen können. Das vorliegende Diskussionspapier zeichnet als Zukunftsszenario global kooperative, kreislauforientierte Regionalwirtschaften, die weltweite Ungleichheiten in Chancen und Lebensqualität grundlegend vermindern und dabei gleichsam die natürlichen Lebensgrundlagen dauerhaft bewahrt werden.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Oceanography and Applied Ocean Science and Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2020.

Description: The redox cycling of oxygen between O2, water, and intermediate redox states including hydrogen peroxide and superoxide, has profound impact on the availability and distribution of dissolved O2, the habitability of the marine biosphere, and cellular metabolic and physiological reactions that utilize O2. The sum total of processes that produce, consume, and exchange atoms with O2 in the atmosphere, oceans, and subsurface leave their isotopic fingerprints on the abundance of the three stable isotopes of O2 in the environment. In this thesis, I explore two aspects of the oxygen cycle in the past and present. First, I investigate the ability of manganese (Mn) oxide minerals to capture and retain the oxygen isotopic signature of dissolved O2 during the oxidation of aqueous Mn(II) to Mn-oxide minerals. I determine that approximately half of the oxygen atoms in Mn(III,IV) oxides are directly incorporated from dissolved oxygen, and use isotope labeling techniques to further constrain how the dissolved oxygen isotope signature may be determined from that of Mn oxides. I perform an in-depth characterization of a ferromanganese crust from the central Pacific and, using triple oxygen isotope measurements, demonstrate that Mn oxides in ferromanganese crusts from around the world retain signatures of dissolved oxygen for at least 30 million years. I next turn to a previously unconsidered aspect of the global oxygen cycle: dark, extracellular superoxide production by marine microbes. I measure extracellular superoxide production rates by some of the ocean’s most abundant organisms. I use these rates along with previous measurements to estimate that extracellular superoxide production yields a net sink of 5-19% of marine dissolved oxygen. Ultimately, the degree to which superoxide production is a sink of oxygen lies in the fate of its primary decay product, hydrogen peroxide. I determine the range of oxidative and reductive decay of hydrogen peroxide across a range of environmental conditions in a meromictic pond, thus validating several assumptions from our global estimate. Altogether, this thesis illuminates a path toward investigating the oxygen cycle on million-year timescales in Earth’s recent past and demonstrates the importance of microbial superoxide production in the biogeochemical cycling of O2.

Description: This work was funded by the following grants and organizations: NASA Earth and Space Science Fellowship (NNX15AR62H), MIT Praecis Presidential Graduate Fellowship, NASA Exobiology (NNX15AM046), NSF-OCE grant 1355720, WHOI Ocean Ventures Fund, MIT Student Assistance Fund, WHOI Academic Programs Office, and the Stanford Synchrotron Radiation Lightsource. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DEAC02-76SF00515.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Oceanography and Microbial Biogeochemistry at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2020.

Description: Marine microbes play key roles in global biogeochemistry by mediating chemical transformations and linking nutrient cycles to one another. A major goal in oceanography is to predict the activity of marine microbes across disparate ocean ecosystems. Towards this end, molecular biomarkers are important tools in chemical oceanography because they allow for both the observation and interpretation of microbial behavior. In this thesis, I use molecular biomarkers to develop a holistic, systems biology approach to the study of marine microbes. I begin by identifying unique patterns in the biochemical sensory systems of marine bacteria and suggest that these represent a specific adaptation to the marine environment. Building from this, I focus on the prevalent marine nitrogen fixer Trichodesmium, whose activity affects global nitrogen, carbon, phosphorus, and trace metal cycles. A metaproteomic survey of Trichodesmium populations identified simultaneous iron and phosphate co-stress throughout the tropical and subtropical oceans, demonstrating that this is caused by the biophysical limits of membrane space and nutrient diffusion. Tackling the problem at a smaller scale, I investigated the metaproteomes of individual Trichodesmium colonies captured from a single field site, and identified significant variability related to iron acquisition from mineral particles. Next, I investigated diel proteomes of cultured Trichodesmium erythraeum sp. IMS101 to highlight its physiological complexity and understand how and why nitrogen fixation occurs in the day, despite the incompatibly of the nitrogenase enzyme with oxygen produced in photosynthesis. This thesis develops a fundamental understanding of how Trichodesmium and other organisms affect, and are affected by, their surroundings. It indicates that a reductionist approach in which environmental drivers are considered independently may not capture the full complexity of microbechemistry interactions. Future work can focus on benchmarking and calibration of the protein biomarkers identified here, as well as continued connection of systems biology frameworks to the study of ocean chemistry.

Description: This work was supported by an MIT Walter A. Rosenblith Presidential Fellowship and a National Science Foundation Graduate Research Program Fellowship under grant number 1122274 [N.Held]. This work was also supported by the WHOI Ocean Ventures fund [N.Held], Gordon and Betty Moore Foundation grant number 3782 [M.Saito], National Science Foundation grant numbers OCE-1657766 [M.Saito], EarthCube-1639714 [M.Saito], OCE-1658030 [M.Saito], and OCE-1260233 [M.Saito], and funding from the UK Natural Environment Research Council (NERC) under grants awarded to C.M. (NE/N001079/1) and M.L. (NE/N001125/1). This thesis was completed during a writing residency at the Turkeyland Cove Foundation.

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zakem, E. J., Mahadevan, A., Lauderdale, J. M., & Follows, M. J. Stable aerobic and anaerobic coexistence in anoxic marine zones. ISME Journal, 14, (2019): 288–301, doi: 10.1038/s41396-019-0523-8.

Description: Mechanistic description of the transition from aerobic to anaerobic metabolism is necessary for diagnostic and predictive modeling of fixed nitrogen loss in anoxic marine zones (AMZs). In a metabolic model where diverse oxygen- and nitrogen-cycling microbial metabolisms are described by underlying redox chemical reactions, we predict a transition from strictly aerobic to predominantly anaerobic regimes as the outcome of ecological interactions along an oxygen gradient, obviating the need for prescribed critical oxygen concentrations. Competing aerobic and anaerobic metabolisms can coexist in anoxic conditions whether these metabolisms represent obligate or facultative populations. In the coexistence regime, relative rates of aerobic and anaerobic activity are determined by the ratio of oxygen to electron donor supply. The model simulates key characteristics of AMZs, such as the accumulation of nitrite and the sustainability of anammox at higher oxygen concentrations than denitrification, and articulates how microbial biomass concentrations relate to associated water column transformation rates as a function of redox stoichiometry and energetics. Incorporating the metabolic model into an idealized two-dimensional ocean circulation results in a simulated AMZ, in which a secondary chlorophyll maximum emerges from oxygen-limited grazing, and where vertical mixing and dispersal in the oxycline also contribute to metabolic co-occurrence. The modeling approach is mechanistic yet computationally economical and suitable for global change applications.

Description: We are grateful for the thorough and thoughtful comments of two anonymous reviewers. We also thank Andrew Babbin for helpful comments. EJZ was supported by the Simons Foundation (Postdoctoral Fellowship in Marine Microbial Ecology). AM was supported by the Office of Naval Research (ONR #N000-14-15-1-2555). JML was supported by U.S. National Science Foundation (NSF #OCE-1259388). MJF was supported by the Gordon and Betty Moore Foundation (GBMF #3778) and the Simons Foundation: the Simons Collaboration on Ocean Processes and Ecology (SCOPE #329108) and the Simons Collaboration on Computational Biogeochemical Modeling of Marine Ecosystems (CBIOMES #549931).

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ponnudurai, R., Heiden, S. E., Sayavedra, L., Hinzke, T., Kleiner, M., Hentschker, C., Felbeck, H., Sievert, S. M., Schlüter, R., Becher, D., Schweder, T., & Markert, S. Comparative proteomics of related symbiotic mussel species reveals high variability of host-symbiont interactions. ISME Journal, 14, (2019): 649–656, doi: 10.1038/s41396-019-0517-6.

Description: Deep-sea Bathymodiolus mussels and their chemoautotrophic symbionts are well-studied representatives of mutualistic host–microbe associations. However, how host–symbiont interactions vary on the molecular level between related host and symbiont species remains unclear. Therefore, we compared the host and symbiont metaproteomes of Pacific B. thermophilus, hosting a thiotrophic symbiont, and Atlantic B. azoricus, containing two symbionts, a thiotroph and a methanotroph. We identified common strategies of metabolic support between hosts and symbionts, such as the oxidation of sulfide by the host, which provides a thiosulfate reservoir for the thiotrophic symbionts, and a cycling mechanism that could supply the host with symbiont-derived amino acids. However, expression levels of these processes differed substantially between both symbioses. Backed up by genomic comparisons, our results furthermore revealed an exceptionally large repertoire of attachment-related proteins in the B. thermophilus symbiont. These findings imply that host–microbe interactions can be quite variable, even between closely related systems.

Description: Thanks to captain, crew, and pilots of the research vessels Atlantis (ROV Jason cruise AT26–10 in 2014) and Meteor (cruise M82–3 in 2010). We thank Jana Matulla, Sebastian Grund, and Annette Meuche for excellent technical assistance during sample preparation, MS measurements in the Orbitrap Classic, and TEM imaging preparation, respectively. We appreciate Nikolaus Leisch’s help with TEM image interpretation, Inna Sokolova’s advice on bivalve physiology, and Marie Zühlke’s support during manuscript revision. RP was supported by the EU-funded Marie Curie Initial Training Network ‘Symbiomics’ (project no. 264774) and by a fellowship of the Institute of Marine Biotechnology e.V. TH was supported by the German Research Foundation DFG (grant MA 6346/2–1 to SM). The Atlantis cruise was funded by a grant of the US National Science Foundation’s Dimensions of Biodiversity program to SMS (OCE-1136727).

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Miller, C. A., Holm, H. C., Horstmann, L., George, J. C., Fredricks, H. F., Van Mooy, B. A. S., & Apprill, A. Coordinated transformation of the gut microbiome and lipidome of bowhead whales provides novel insights into digestion. ISME Journal, 14, (2019): 688-701, doi: 10.1038/s41396-019-0549-y.

Description: Whale digestion plays an integral role in many ocean ecosystems. By digesting enormous quantities of lipid-rich prey, whales support their energy intensive lifestyle, but also excrete nutrients important to ocean biogeochemical cycles. Nevertheless, whale digestion is poorly understood. Gastrointestinal microorganisms play a significant role in vertebrate digestion, but few studies have examined them in whales. To investigate digestion of lipids, and the potential contribution of microbes to lipid digestion in whales, we characterized lipid composition (lipidomes) and bacterial communities (microbiotas) in 126 digesta samples collected throughout the gastrointestinal tracts of 38 bowhead whales (Balaena mysticetus) harvested by Alaskan Eskimos. Lipidomes and microbiotas were strongly correlated throughout the gastrointestinal tract. Lipidomes and microbiotas were most variable in the small intestine and most similar in the large intestine, where microbiota richness was greatest. Our results suggest digestion of wax esters, the primary lipids in B. mysticetus prey representing more than 80% of total dietary lipids, occurred in the mid- to distal small intestine and was correlated with specific microorganisms. Because wax esters are difficult to digest by other marine vertebrates and constitute a large reservoir of carbon in the ocean, our results further elucidate the essential roles that whales and their gastrointestinal microbiotas play in the biogeochemical cycling of carbon and nutrients in high-latitude seas.

Description: Devonshire Foundation (to CAM), Marine Mammal Center, Woods Hole Oceanographic Institution (WHOI; to CAM), WHOI Ocean Life Institute (to AA and CAM), Dalio Foundation’s Dalio Ocean Initiative (now ‘OceanX’) (to AA), National Science Foundation (OCE-1756254 and OPP-1543328 to BASVM). Samples were collected under Department of Commerce National Oceanic and Atmospheric Administration National Marine Fisheries Service permit numbers 17350-00, 17350-01, and 17350-02 to North Slope Borough Department of Wildlife Management.

Description: Submitted in partial fulfillment of the requirements for the degree of of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2020.

Description: The shallow marine ecosystems of coral atolls and the human communities they support are among the most vulnerable to anthropogenic climate change. Sea-level rise threatens to inundate low-lying reef islands, tropical cyclone intensification threatens islands with flooding and erosion, and ocean warming and acidification threaten the health of coral reefs. Unfortunately, the sediment dynamics that shape the morphology of coral reefs and atoll reef islands are poorly understood, hindering predictions of coral atoll responses to climate change forcing. Here, I apply an eclectic set of methods, including numerical modeling, physical lab experiments, and sedimentological analysis, to produce insights into the ways tropical cyclones and waves move sediment on fringing reefs. First, I use a numerical model of hydrodynamics to predict the influence of sea-level rise and wave climate change on sediment transport across a coral atoll fringing reef. I demonstrate that by the end of the century, sea-level rise will reduce sediment transport rates from the fore reef to the beach, but increase transport rates from the reef flat to the beach. Wave climate change will have relatively negligible influence on cross-reef sediment transport. Additionally, I use the weathering of foraminifera tests to produce a sediment proxy of transport duration and direction across atoll reef flats, but demonstrate that the proxy does not clearly identify storm deposits. Second, I execute a series of experiments in an oscillating flow tunnel to constrain the rate at which sediment erodes reef surfaces under waves. I find that the erosion rate increases as a power law of wave orbital velocity, and that amount of sediment has a second-order influence. Finally, I establish grain size in a sediment core retrieved from a blue hole in the Marshall Islands as a proxy for tropical cyclone genesis and, using the results from an ensemble of climate models, demonstrate that enhanced tropical cyclogenesis during the Little Ice Age may have been driven by an anomalously negative Pacific Meridional Mode. This thesis demonstrates the importance of sediment dynamics on the morphology of fringing reefs and atoll reef islands and the sensitivity of those dynamics to centennial climate variability.

Description: Funding for this project was provided by the Strategic Environmental Research and Development Program (SERDP RC-2336).

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Advances in the miniaturization of microelectronics has greatly contributed to the proliferation of small, low cost autonomous underwater vehicles (AUVs). These affordable vehicles offer organizations a flexible platform that can be adapted to support a multitude of research goals. The small size and low entry cost come with a trade off of simple navigation systems, typically dead reckoning (DR) using a speed determined via propeller counts and heading from a low cost micro-electromechanical system (MEMS) inertial measurement unit (IMU), whose error grows unbounded without the availability of a ground referenced fix source and is compounded by the bias present in the speed measurement due to the change in hydrodynamics from the addition of sensors to the hull form. Additionally, some capabilities such as water current velocity measurement traditionally requires the addition of equipment that is not only expensive, but also whose size and power consumption can adversely affect operating characteristics and deployment times. This thesis expands on previous research using one-way travel time inverted USBL (OWTT-iUSBL) to calculate the local current velocity without the addition of a Doppler velocity log (DVL) or acoustic Doppler current profiler (ADCP). A novel extended Kalman filter (EKF) is proposed that, in addition to calculating the current velocity, estimates and corrects for the bias present in the speed measurement as determined by the main vehicle computer. Using data collected on the Charles River at the Massachusetts Institute of Technology (MIT) Sailing Pavilion, it is shown that current velocities can be reasonably calculated using OWTT-iUSBL data as compared to the values calculated using long baseline (LBL) data.

Description: Funding for this thesis research was provided the US Navy Civilian Institutions Office through the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gazitua, M. C., Vik, D. R., Roux, S., Gregory, A. C., Bolduc, B., Widner, B., Mulholland, M. R., Hallam, S. J., Ulloa, O., & Sullivan, M. B. Potential virus-mediated nitrogen cycling in oxygen-depleted oceanic waters. Isme Journal, (2020), doi:10.1038/s41396-020-00825-6.

Description: Viruses play an important role in the ecology and biogeochemistry of marine ecosystems. Beyond mortality and gene transfer, viruses can reprogram microbial metabolism during infection by expressing auxiliary metabolic genes (AMGs) involved in photosynthesis, central carbon metabolism, and nutrient cycling. While previous studies have focused on AMG diversity in the sunlit and dark ocean, less is known about the role of viruses in shaping metabolic networks along redox gradients associated with marine oxygen minimum zones (OMZs). Here, we analyzed relatively quantitative viral metagenomic datasets that profiled the oxygen gradient across Eastern Tropical South Pacific (ETSP) OMZ waters, assessing whether OMZ viruses might impact nitrogen (N) cycling via AMGs. Identified viral genomes encoded six N-cycle AMGs associated with denitrification, nitrification, assimilatory nitrate reduction, and nitrite transport. The majority of these AMGs (80%) were identified in T4-like Myoviridae phages, predicted to infect Cyanobacteria and Proteobacteria, or in unclassified archaeal viruses predicted to infect Thaumarchaeota. Four AMGs were exclusive to anoxic waters and had distributions that paralleled homologous microbial genes. Together, these findings suggest viruses modulate N-cycling processes within the ETSP OMZ and may contribute to nitrogen loss throughout the global oceans thus providing a baseline for their inclusion in the ecosystem and geochemical models.

Description: We thank Sullivan Lab members and Heather Maughan for comments on the paper, Bess Ward for her contribution in the N-cycle context of our story, Kurt Hanselmann for his assistance in the calculations of the Gibbs-free energies, and the scientific party and crew of the R/V Atlantis (grant OCE-1356056 to MRM) for the sampling opportunity and support at sea. This work was funded in part by awards from the Agouron Institute to OU and MBS, a Gordon and Betty Moore Foundation Investigator Award (#3790) and NSF Biological Oceanography Awards (#1536989 and #1829831) to MBS, and the Millennium Science Initiative (grant ICN12_019-IMO) to OU. The work conducted by the U.S. Department of Energy Joint Genome Institute is supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC02-05CH11231.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Babbin, A. R., Tamasi, T., Dumit, D., Weber, L., Rodríguez, M. V. I., Schwartz, S. L., Armenteros, M., Wankel, S. D., & Apprill, A. Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals. ISME Journal, (2020), doi:10.1038/s41396-020-00845-2.

Description: Coral reef health depends on an intricate relationship among the coral animal, photosynthetic algae, and a complex microbial community. The holobiont can impact the nutrient balance of their hosts amid an otherwise oligotrophic environment, including by cycling physiologically important nitrogen compounds. Here we use 15N-tracer experiments to produce the first simultaneous measurements of ammonium oxidation, nitrate reduction, and nitrous oxide (N2O) production among five iconic species of reef-building corals (Acropora palmata, Diploria labyrinthiformis, Orbicella faveolata, Porites astreoides, and Porites porites) in the highly protected Jardines de la Reina reefs of Cuba. Nitrate reduction is present in most species, but ammonium oxidation is low potentially due to photoinhibition and assimilatory competition. Coral-associated rates of N2O production indicate a widespread potential for denitrification, especially among D. labyrinthiformis, at rates of ~1 nmol cm−2 d−1. In contrast, A. palmata displays minimal active nitrogen metabolism. Enhanced rates of nitrate reduction and N2O production are observed coincident with dark net respiration periods. Genomes of bacterial cultures isolated from multiple coral species confirm that microorganisms with the ability to respire nitrate anaerobically to either dinitrogen gas or ammonium exist within the holobiont. This confirmation of anaerobic nitrogen metabolisms by coral-associated microorganisms sheds new light on coral and reef productivity.

Description: Research was conducted in the Gardens of the Queen, Cuba in accordance with the requirements of the Republic of Cuba, conducted under permit NV2370 and NV2568 issued by the Ministerio de Relaciones Exteriores. We gratefully acknowledge funding for this research by MIT Sea Grant award #2018-DOH-49-LEV, Simons Foundation award #622065, and MIT ESI seed funding to ARB, the MIT Montrym, Ferry, and mTerra Seed Grant Funds, and the generous contributions by Dr Bruce L. Heflinger.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Seyler, L. M., Trembath-Reichert, E., Tully, B. J., & Huber, J. A. Time-series transcriptomics from cold, oxic subseafloor crustal fluids reveals a motile, mixotrophic microbial community. Isme Journal, (2020), doi:10.1038/s41396-020-00843-4.

Description: The oceanic crustal aquifer is one of the largest habitable volumes on Earth, and it harbors a reservoir of microbial life that influences global-scale biogeochemical cycles. Here, we use time series metagenomic and metatranscriptomic data from a low-temperature, ridge flank environment representative of the majority of global hydrothermal fluid circulation in the ocean to reconstruct microbial metabolic potential, transcript abundance, and community dynamics. We also present metagenome-assembled genomes from recently collected fluids that are furthest removed from drilling disturbances. Our results suggest that the microbial community in the North Pond aquifer plays an important role in the oxidation of organic carbon within the crust. This community is motile and metabolically flexible, with the ability to use both autotrophic and organotrophic pathways, as well as function under low oxygen conditions by using alternative electron acceptors such as nitrate and thiosulfate. Anaerobic processes are most abundant in subseafloor horizons deepest in the aquifer, furthest from connectivity with the deep ocean, and there was little overlap in the active microbial populations between sampling horizons. This work highlights the heterogeneity of microbial life in the subseafloor aquifer and provides new insights into biogeochemical cycling in ocean crust.

Description: The Gordon and Betty Moore Foundation sponsored most of the observatory components at North Pond through grant GBMF1609. This work was supported by NSF OCE-1062006, OCE-1745589 and OCE-1635208 to J.A.H. E.T.R. was supported by a NASA Postdoctoral Fellowship with the NASA Astrobiology Institute and a L’Oréal USA For Women in Science Fellowship. The Center for Dark Energy Biosphere Investigations (C-DEBI OCE-0939564) also supported the participation of J.A.H. and B.T. This is C-DEBI contribution number 548.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: This thesis explores the volatile content of the mantle, subducted oceanic crust, and arc magmas as well as the structure of slow spreading ocean crust and the heterogeneity of Earth’s upper mantle. In Chapter 2, I directly explore the halogen (F and Cl) content of mantle minerals in situ, then use these measurements to assess the halogen content of the upper mantle. In Chapter 3, I investigate the volatile content of Raspas eclogites (SW Ecuador), a proxy for deeply subducted oceanic crust, to evaluate volatile transfer from crustal generation at divergent plate boundaries (e.g., mid-ocean ridges) to recycling of ocean crust at subduction zones. In Chapter 4, I use the H2O content of nominally anhydrous minerals in plutonic arc cumulates to elucidate the H2O content of the melts from which the rocks crystallized. In this way, I assert that primitive arc magmas may contain 4–10 wt.% H2O and through fractional crystallization up to ~20 wt.% H2O, making them far more hydrous than traditional methods (i.e., olivine-hosted melt inclusions) surmise. In Chapter 5, I show that mantle peridotite exposed along the 16ºN region of the Mid-Atlantic Ridge originated in an arc setting and has been remixed into subridge mantle, indicating that the sub-ridge mantle is more heterogeneous and depleted than inferences made from mid-ocean ridge basalts suggest. Chapter 6 surveys the life cycle of oceanic core complexes through zircon geochronology and posits an updated framework for understanding the termination of oceanic core complexes, and more broadly oceanic detachment faults. Together, this contribution highlights the chemical heterogeneity of the mantle, and quantifies the full extent of volatiles hosted by mantle and crustal reservoirs.

Description: The Stanley Watson Fellowship (WHOI) provided financial support during my first year of graduate school. The Academic Programs Office Ocean Venture Fund (WHOI) provided seed funding which initiated Chapters 3 and 4, and ultimately led to two funded NSF proposals. These resources are vital to JP students, and I am incredibly grateful for them. Primary support was provided by the National Science Foundation grants to Veronique Le Roux (EAR P&G #1524311, #1839128, #1855302) and Henry Dick (MG&G #1637130, #1657983).

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: This thesis presents an Autonomous Underwater Glider (AUG) architecture that is intended for basin-scale unattended survey of Arctic sea-ice. The distinguishing challenge for AUG operations in the Arctic environment is the presence of year-round sea-ice cover which prevents vehicle surfacing for localization updates and shore-side communication. Due to the high cost of operating support vessels in the Arctic, the proposed AUG architecture minimizes external infrastructure requirements to brief and infrequent satellite updates on the order of once per day. This is possible by employing onboard acoustic sensing for sea-ice observation and navigation, along with intelligent management of onboard resources. To enable unattended survey of Arctic sea-ice with an AUG, this thesis proposes a hierarchical acoustics-based sea-ice characterization scheme to perform science data collection and assess environment risk, a multi-factor terrain-aided navigation method that leverages bathymetric features and active ocean current sensing to limit localization error, and a set of energy-optimal propulsive and hotel policies that react to evolving environmental conditions to improve AUG endurance. These methods are evaluated with respect to laboratory experiments and preliminary field data, and future Arctic sea-ice survey mission concepts are discussed.

Description: Support for this research was provided through the National Science Foundation Navigating the New Arctic Grant #1839063 and the NASA PSTAR Grant #NNX16AL08G. Additionally, this research was supported by the Walter A. Rosenblith Presidential Fellowship.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Oceanography/Applied Ocean Science and Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Underwater Vehicles generally have control fins located only near their aft end, for making controllable changes in directions. This design allows for stability of control; but, the turns are typically large in comparison to the vehicle’s body length. Some bony fish, such as tuna, however, have deployable fins located towards the front of their body, in addition to their other fins. Their deployable fins allow them to modulate their hydrodynamic behavior in response to their environment. Tunas keep these fins retracted during steady cruising, and then deploy them during rapid maneuvers. However, the details of these hydrodynamic effects are not well understood. To investigate this phenomena, using a REMUS 100 as a model, a pair of vertical fins was added at different hull positions, to investigate the effects of fin location on the horizontal plane hydrodynamics, through: stability parameters, nonlinear simulation, and towing tank experiments. Depending on the added fin location, the vehicle stability changed, thereby affecting the maneuverability. As fins were placed forward on the vehicle, maneuverability increased, with effects tapering off at 0.2 BL ahead of the vehicle's center of buoyancy. This investigation explored how rigid underwater vehicles could benefit from added fins, without drastically changing the design of current vehicles.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Oceanographic Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Sea ice thickness has long been an under-measured quantity, even in the satellite era. The snow surface elevation, which is far easier to measure, cannot be directly converted into sea ice thickness estimates without knowledge or assumption of what proportion of the snow surface consists of snow and ice. We do not fully understand how snow is distributed upon sea ice, in particular around areas with surface deformation. Here, we show that deep learning methods can be used to directly predict snow depth, as well as sea ice thickness, from measurements of surface topography obtained from laser altimetry. We also show that snow surfaces can be texturally distinguished, and that texturally-similar segments have similar snow depths. This can be used to predict snow depth at both local (sub-kilometer) and satellite (25 km) scales with much lower error and bias, and with greater ability to distinguish inter-annual and regional variability than current methods using linear regressions. We find that sea ice thickness can be estimated to ∼20% error at the kilometer scale. The success of deep learning methods to predict snow depth and sea ice thickness suggests that such methods may be also applied to temporally/spatially larger datasets like ICESat-2.

Description: This research was funded by National Aeronautics and Space Administration grant numbers NNX15AC69G and 80NSSC20K0972, the US National Science Foundation grant numbers ANT-1341513, ANT-1341606, ANT-1142075 and ANT-1341717, and the WHOI Academic Programs Office.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Oceanic fronts at the mesoscale and submesoscale are associated with enhanced vertical motion, which strengthens their role in global biogeochemical cycling as hotspots of primary production and subduction of carbon from the surface to the interior. Using process study models, theory, and field observations of biogeochemical tracers, this thesis improves understanding of submesoscale vertical tracer fluxes and their influence on carbon cycling. Unlike buoyancy, vertical transport of biogeochemical tracers can occur both due to the movement of isopycnals and due to motion along sloping isopycnals. We decompose the vertical velocity below the mixed layer into two components in a Lagrangian frame: vertical velocity along sloping isopycnal surfaces and the adiabatic vertical velocity of isopycnal surfaces and demonstrate that vertical motion along isopycnal surfaces is particularly important at submesoscales (1-10 km). The vertical flux of nutrient, and consequently the new production of phytoplankton depends not just on the vertical velocity but on the relative time scales of vertical transport and nutrient uptake. Vertical nutrient flux is maximum when the biological timescale of phytoplankton growth matches the vertical velocity frequency. Export of organic matter from the surface and the interior requires water parcels to cross the mixed layer base. Using Lagrangian analysis, we study the dynamics of this process and demonstrate that geostrophic and ageostrophic frontogenesis drive subduction along density surfaces across the mixed layer base. Along-front variability is an important factor in subduction. Both the physical and biological modeling studies described above are used to interpret observations from three research cruises in the Western Mediterranean. We sample intrusions of high chlorophyll and particulate organic carbon below the euphotic zone that are advected downward by 100 meters on timescales of days to weeks. We characterize the community composition in these subsurface intrusions at a lateral resolution of 1–10 km. We observe systematic changes in community composition due to the changing light environment and differential decay of the phytoplankton communities in low-light environments, along with mixing. We conclude that advective fluxes could make a contribution to carbon export in subtropical gyres that is equal to the sinking flux.

Description: The work in this dissertation was funded by a NDSEG fellowship, Martin Fellowship, Grassle fellowship, Montrym grant, WHOI Academic Programs Office, and Office of Naval Research CALYPSO DRI grant N00014-16-1-3130.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Operations in the Arctic Ocean are increasingly important due to the changing environment and the resulting global implications. These changes range from the availability of new global trade routes, accessibility of newly available resources in the area, and national security interests of the United States in the region. It’s necessary to build a greater understanding of the undersea environment and how it’s changing since these environmental changes have a direct impact on adjusting future operations in the region and looming global changes as less Arctic ice is present. The recent presence of the Beaufort Lens is changing the acoustic propagation paths throughout the Arctic region. Here a network of buoys were employed to communicate with an Autonomous Undersea Vehicle (AUV) while it operated under the ice throughout the Beaufort Lens with the goal of achieving near GPS quality navigation. The acoustic communications paths were compared using a vertical array throughout the Beaufort Lens. This beam forming was compared to the prediction from BELLHOP. As well, since acoustic communications are affected by multi-path, attenuation and interference from other sources it was interesting to note that bottom bounce was sometimes a reliable acoustic path.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Chromium (Cr) isotopes have shown great potential as a paleo-redox proxy to trace the redox conditions of ancient oceans and atmosphere. However, its cycling in modern environments is poorly constrained. In my thesis, I attempt to fill in the gap of our understanding of chromium cycling in the modern ocean, with a focus on the redox processes in global oxygen deficient zones (ODZs). Firstly, we developed a method to analyze Cr isotopes of different Cr redox species. Tests on processing conditions demonstrated its robustness in obtaining accurate Cr isotope data. It is applicable to both frozen and fresh samples. This method allows us to investigate the redox cycling of Cr that is hard to unravel by existing total Cr methods. Secondly, in the Eastern Tropical North Pacific (ETNP), Eastern Tropical South Pacific (ETSP) and Arabian Sea ODZs, their total dissolved Cr profiles show preferential reduction of isotopically light Cr(VI) to Cr(III), which is scavenged and exported to deeper oceans. Applying our new method to ETNP and ETSP ODZ seawater samples, we observed Cr(VI) reduction in both ODZs with a similar fractionation factor. This indicates similar mechanisms may be controlling Cr(VI) reduction in the two ODZs. Cr(III) maximum coincides with Fe(II) and secondary nitrite maximums in the upper core of both ODZs. Shipboard incubations with spiked Fe(II) showed fast Cr(VI) reduction occurring in the ETNP ODZ. But neither Fe(II) nor microbes were reducing Cr(VI) directly. Thirdly, we calculated the isotope effects of Cr scavenging in the ETNP and ETSP ODZs. Thetwo ODZs show a similar isotope partitioning during Cr scavenging. And spatial variability is observed in the ETNP ODZ. Our calculated scavenged Cr isotope ratio is lighter than that of the total dissolved Cr from the same depth. It is also comparable to that of reducing or anoxic sediments, which implies that Cr isotopes can be used as an archive for local redox conditions.

Description: This research was supported by an anonymous MIT Fellowship, Praceis Presidential Fellowship, Frederick A. Middleton Fellowship, the US National Science Foundation (NSF Award No. OCE-1459287, OCE-1736996, OCE-1924050 and DEB-1542240) and the Center for Microbial Oceanography: Research and Education (C-MORE, NSF-OIA Award No. EF-0424599).

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2022.

Description: Detection, classification, localization, and tracking (DCLT) of unmanned underwater vehicles (UUVs) in the presence of shipping traffic is a critical task for passive acoustic harbor security systems. In general, vessels can be tracked by their unique acoustic signature due to machinery vibration and cavitation noise. However, cavitation noise of UUVs is considerably quieter than ships and boats, making detection significantly more challenging. In this thesis, I demonstrated that it is possible to passively track a UUV from its highfrequency motor noise using a stationary array in shallow-water experiments with passing boats. First, causes of high frequency tones were determined through direct measurements of two UUVs at a range of speeds. From this analysis, common and dominant features of noise were established: strong tones at the motor’s pulse-width modulated frequency and its harmonics. From the unique acoustic signature of the motor, I derived a high-precision, remote sensing method for estimating propeller rotation rate. In shallow-water UUV field experiments, I demonstrated that detecting a UUV from motor noise, in comparison to broadband noise from the vehicle, reduces false alarms from 45% to 8.4% for 90% true detections. Beamforming on the motor noise, in comparison to broadband noise, improved the bearing accuracy by a factor of 3.2×. Because the signal is also high-frequency, the Doppler effect on motor noise is observable and I demonstrate that range rate can be measured. Furthermore, measuring motor noise was a superior method to the “detection of envelope modulation on noise” algorithm for estimating the propeller rotation rate. Extrapolating multiple measurements from the motor signature is significant because Bearing-Doppler-RPM measurements outperform traditional bearing-Doppler target motion analysis. In the unscented Kalman filter implementation, the tracking solution accuracy for bearing, bearing rate, range, and range rate improved by a factor 2.2×, 15.8×, 3.1×, and 6.2× respectively. These findings are significant for improving UUV localization and tracking, and for informing the next-generation of quiet UUV propulsion systems.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biological Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 2020.

Description: Highly productive marine microbial communities in the coastal Southern Ocean sustain the broader Antarctic ecosystem and play a key role in Earth’s climate via the biological pump. Regional phytoplankton growth is primarily limited by iron and co-limited by cobalamin (vitamin B12), a trace cobalt-containing organometallic compound only synthesized by some bacteria and archaea. These micronutrients impact primary production and the microbial ecology of the two keystone phytoplankton types: diatoms and Phaeocystis antarctica. This thesis investigates microbe-driven cobalamin cycling in Antarctic seas across multiple spatiotemporal scales. I conducted laboratory culture experiments with complementary proteomics and transcriptomics to investigate the B12-ecophysiology of P. antarctica strain CCMP 1871 morphotypes under iron-B12 co-limitation. We observed colony formation under higher iron treatments, and a facultative use of B12-dependent (MetH) and B12-independent (MetE) methionine synthase isoforms in response to vitamin availability, demonstrating that this strain is not B12-auxotrophic. Through comparative ’omics, we identified a putative MetE protein in P. antarctica abundant under low B12, which is also found in other marine microbes. Across Antarctic seas, community-scale cobalt and B12 uptake rates were measured by 57Co radiotracer incubation experiments and integrated with hydrographic and phytoplankton pigment data. I observed significant correlations between uptake fluxes and environmental variables, providing evidence for predominantly diatom-driven uptake of these micronutrients in warmer, fresher surface waters with notable regional differences. To date, this work is the most comprehensive attempt to elucidate the processes governing the co-cycling of cobalt and B12 in any marine system. At the ecosystem-scale, I developed and tested a hypothesis of micronutrient-driven community dynamics through a trait-based model with cross-feeding interactions. The model demonstrates how the observed seasonal succession of springtime P. antarctica from solitary to colonial cells, bacterioplankton, and summertime diatoms may be explained by the microbial cycling of iron, dissolved organic carbon, and B12. Overall, this dissertation provides new information about the micronutrient-driven ecology of Antarctic marine microbes and adds to our understanding of the interconnections between organismal life cycle, trace metals, and trace organics in marine environments.

Description: My training as a scientist during my time in the MIT–WHOI Joint Program (2014-2020) and the work presented in this dissertation were financially supported by the Academic Programs Office (APO) at the Woods Hole Oceanographic Institution (WHOI) and various funding agencies. My first semester was supported by the WHOI Von Damm Fellowship (2014). Subsequent years and endeavors were supported by awards from the Gordon and Betty Moore Foundation to Professor Michael Follows (Award 3778, M.J.F.) and Simons Collaboration on Computational Biogeochemical Modeling of Marine Ecosystems (Award 549931, M.J.F.); National Science Foundation (NSF) grant to Dr. Stephanie Dutkiewicz (Grant number 1434007, S.D.), and NSF Office of Polar Program (OPP) grant to Dr. Makoto Saito (M.S.) for the CICLOPS research expedition (OPP-1643684, OPP-1643845, and OPP-1644073).

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biological Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Little is known about how Atlantic hurricane activity changes on long timescales. This thesis uses proxy development and proxy-model integration to constrain the spatiotemporal variability in hurricane activity in the Bahama Archipelago over the past millennium. I present annually-resolved archives of storm activity derived from sediment cores from blue holes on three islands in the Bahama Archipelago: South Andros, Long Island, and Middle Caicos. Dramatic differences between these records suggest localized controls on the hurricane patterns observed by each island. Thus, compiling these records together more accurately captures regional variations in hurricane strikes. Integrating our new Bahama Archipelago compilation with compiled paleohurricane records from the U.S. coastline indicates shifting patterns of hurricane activity over the past millennium between the Gulf Coast and the Bahama Archipelago/New England. Finally, I address whether variability in hurricane strikes observed in Bahamian paleohurricane records is related to climate or random variability using hurricane model output. The signal observed in any individual record of paleohurricane activity from the Bahama Archipelago is driven more by random variability in hurricane tracks than by climate. This thesis lays the groundwork for creating high-resolution paleohurricane records from blue holes and using hurricane models to inform our interpretations of these records.

Description: This work was funded by the National Science Foundation Graduate Research Fellowship (to E.J.W.), National Science Foundation grant OCE-1356708 (to J.P.D. and P.J.vH.) and the Dalio Explore Foundation.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Speleothems, or sedimentary rocks formed in caves, act as valuable archives of past climate change due to their suitability for U-series dating and high-resolution proxy analysis. These records can provide insights into water availability and controls on hydrology prior to the instrumental record. In this thesis, I present three records from newly-analyzed Mexican stalagmites using stable isotope (oxygen and carbon) and trace element to calcium (Mg/Ca and Sr/Ca) ratios as proxies for changing hydroclimate. Chapter 2 presents a precisely dated, mid-Holocene record of high rainfall and limited precipitation variability in the Yucatan Peninsula, Mexico. Chapters 3 and 4 present novel climate records from northeastern Mexico, an understudied region of North America. Both records come from cave sites within the Mexican arid zone, which is simultaneously experiencing increased water scarcity and a rapidly growing population. In Chapter 3, I examine a speleothem from the first millennium of the Common Era, which showed that there is a precipitation dipole between northern and southern Mexico. Chapter 4 highlights, for the first time at decadal resolution, the northeast Mexican response to the 8.2 ka event and the Younger Dryas. These chapters show that the San Luis Potosí region is vulnerable to droughts under multiple climate mean states, and is subject to drying as Atlantic Meridional Overturning Circulation weakens due to anthropogenic climate change. The climate records detailed in this thesis improve our understanding of controls on Mexican hydroclimate and can serve as benchmarks for climate models.

Description: This work was funded by US National Science Foundation (NSF) grants AGS-1702848 (M. Medina-Elizalde), AGS–1502877 (S. Burns), AGS-1804512 and AGS-1806090 (K. Johnson and D. McGee). I was also supported by the NSF Graduate Research Fellowship and the MIT School of Science Dean’s Fellowship. Fieldwork and analysis were funded by the WHOI Ocean Ventures Fund, the MIT EAPS Student Research Fund, and the MIT International Science and Technology Initiatives (MISTI) Mexico program. Initial work for this project was also supported by UC MEXUS-CONACYT Collaborative Grant from the University of California Institute for Mexico and the United States (UC MEXUS CN-16-120). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2021.

Description: The existence of a marine phosphorus (P) redox cycle was recently confirmed when phosphonates, organophosphorus compounds with P in the (III) oxidation state, were found in high molecular weight dissolved organic matter. Although some features of the P redox cycle have come to light since the discovery of phosphonates, many aspects of phosphonate production, cycling and fate remain unknown. To address these gaps in our understanding, we studied phosphonate cycling in the Eastern Mediterranean Sea, a chronically P-limited basin, using 33P and enzymatic assays. We showed that phosphonate production was low but consumption was high, suggesting that phosphonate production and consumption may be spatially or temporally decoupled. We also explored phosphonate production in the model marine cyanobacterium Prochlorococcus SB. Using 31P NMR, we found Prochlorococcus SB allocates ~50% of its cellular P to phosphonates. Allocation of P to phosphonates was conserved under P-limitation, and further investigation revealed phosphonates were associated with proteins. The discovery of phosphonoproteins in Prochlorococcus SB opens new perspectives on the biochemical function of phosphonates and their role in P-cycling. Finally, we developed a new P-targeted method to characterize marine organophosphorus compounds using liquid chromatography coupled to electrospray ionization and inductively coupled plasma mass spectrometry.

Description: This work was supported by the Simons Foundation under grant numbers POP49476 and 721227 [D. Repeta], the Gordon and Betty Moore Foundation under the grant number 6000 [D. Repeta] and the National Science Foundation OCE under the grant number 1634080 [D. Repeta].

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geophysics at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: This thesis focuses on interpreting geophysical and geochemical observables in terms of the thermomechanical state of the lithosphere. In Chapter 1, I correlate lower crustal rheology with seismic wave speed. Compositional variation is required to explain half of the total variability in predicted lower crustal stress, implying that constraining regional lithology is important for lower crustal geodynamics. In Chapter 2, I utilize thermobarometry, diffusion models, and thermodynamic modelling to constrain the ultra-high formation conditions and cooling rates of the Gore Mountain Garnet Amphibolite in order to understand the rheology of the lower crust during orogenic collapse. In Chapter 3, I interpret geophysical data along a 74 Myr transect in the Atlantic to the temporal variability and relationship of crustal thickness and normal faults. In Chapter 4, I constrain the error present in the forward-calculation of seismic wave speed from ultramafic bulk composition. I also present a database and toolbox to interpret seismic wave speeds in terms of temperature and composition. Finally, in Chapter 5 I apply the methodology from Chapter 4 to interpret a new seismic tomographic model in terms of temperature, density, and composition in order to show that the shallow lithospheric roots are density unstable.

Description: Funding for this research was provided by an MIT Presidential Fellowship, MIT Student Research Funds, the National Science Foundation Division of Earth Sciences (EAR) and Ocean Sciences (OCE) grants EAR-16-24109, EAR-17-22932, EAR-17-22935, OCE-14-58201, and SCEC Awards 16106 and 17202., SCEC, Geological Society of America Graduate Student Research Fellowship, WHOI Ocean Venture Fund, and the WHOI Academic Programs Office.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: Observations of hydrographic and dynamical properties on the Middle Atlantic Bight shelf document strong variability at time scales spanning events that last a few days to century long trends. This thesis studies individual processes which impact shelf temperature and velocity structure, and quantifies the mean velocity conditions at the shelf break. Chapter 2 uses model output to study the dynamics that lead to the breakdown of summertime thermal stratification, and how the processes which reduce stratification vary from year to year. In summer, the atmosphere heats the surface of the ocean, leading to strong thermal stratification with warm water overlying cool water. During fall, strong storm events with downwelling-favorable winds are found to be the primary process by which stratification is reduced. The timing of these events and the associated destratification varies from year to year. In Chapter 3, the velocity structure of the New Jersey shelf break is examine, with a focus on the Shelfbreak Jet. Using 25 years of velocity measurements, mean velocity sections of the Shelfbreak Jet are created in both Eulerian and stream coordinate frameworks. The jet exhibits strong seasonal variability, with maximum velocities observed in spring and minimum velocities in summer. Evidence is found that Warm Core Rings, originating from the Gulf Stream and passing through the Slope Sea adjacent to the New Jersey shelf, tend to shift the Shelfbreak Jet onshore of its mean position or entirely shutdown the Shelfbreak Jet’s flow. At interannual timescales, variability in the Shelfbreak Jet velocity is correlated with the temperature on the New Jersey Shelf, with temperature lagging by about 2 months. Chapter 4 focuses on the impact of Warm Core Rings on the velocity and temperature structure on the New Jersey shelf. Warm Core Rings that have higher azimuthal velocities and whose cores approach closer to the shelf are found to exert greater influence on the shelf’s along-shelf velocities, with the fastest and closest rings reversing the direction of flow at the shelf break. Warm Core Rings are also observed to exert long-lasting impacts on the shelf temperature, with faster rings cooling the shelf and slower rings warming the shelf. Seasonal changes in thermal stratification strongly affect how rings alter the shelf temperature. Rings in summer tend to cool the shelf, and rings throughout the rest of the year generally warm the shelf.

Description: This research was funded under WHOI Academic Programs Endowed Funds, NSF #OCE-1634094, and NSF #OCE-1924041.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Small pelagic fishes, also termed forage fishes, represent a critical link between secondary production and myriad top predators in marine ecosystems, including the Northeast US shelf. In this dissertation, I analyze the drivers of forage fish distribution throughout the Northeast US shelf and the drivers of the abundance of the ecologically important northern sand lance. Chapter 2 examines the basic ecology of northern sand lance and uses these insights to identify mechanistic drivers of their abundance. I then explore different scenarios of these drivers to project sand lance abundance through the end of the 21st century, which appears precarious for adult sand lance unless current trajectories change. Chapter 3 analyzes the environmental drivers of the distribution of the six dominant, offshore forage fish species (northern sand lance, Atlantic herring, alewife, blueback herring, Atlantic mackerel, and Atlantic butterfish) on the Northeast US shelf to elucidate the role of environmental covariates in shelf occupancy by these taxa. The results of this chapter indicate shelf occupancy of butterfish and Atlantic mackerel are increasing through time while occupancy of sand lance is decreasing with time. The occurrence of most of these species is also moving deeper and northward with time. Chapter 4 assesses the source-sink dynamics of three sand lance hotspots through Lagrangian particle tracking models simulating larval sand lance transport. Connectivity varies among these hotspots with Georges Bank and Stellwagen Bank having notable retention while the Great South Channel relies on larvae from other hotspots. Retention on Stellwagen Bank and Georges Bank are linked to strong wind events during the larval period of sand lance. Collectively, this dissertation improves our understanding of the dynamics driving variability in the Northeast US shelf forage fish complex, particularly for northern sand lance.

Description: The research within this dissertation was funded by a National Science Foundation Graduate Research Fellowship (awarded to JJS), Woods Hole Sea Grant (NA18OAR4170104, Project No. R/O-57), the Bureau of Ocean Energy Management (IA agreement M17PG0019), and the National Marine Sanctuary Foundation.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: An emerging paradigm posits that the abyssal overturning circulation is driven by bottom-enhanced mixing, which results in vigorous upwelling in the bottom boundary layer (BBL) along the sloping seafloor and downwelling in the stratified mixing layer (SML) above; their residual is the overturning circulation. This boundary-controlled circulation fundamentally alters abyssal tracer distributions, with implications for global climate. Chapter 1 describes how a basin-scale overturning circulation arises from the coupling between the ocean interior and mixing-driven boundary layers over rough topography, such as the sloping flanks of mid-ocean ridges. BBL upwelling is well predicted by boundary layer theory, whereas the compensation by SML downwelling is weakened by the upward increase of the basin-wide stratification, which supports a finite net overturning. These simulated watermass transformations are comparable to best-estimate diagnostics but are sustained by a crude parameterization of boundary layer restratification processes. In Chapter 2, I run a realistic simulation of a fracture zone canyon in the Brazil Basin to decipher the non-linear dynamics of abyssal mixing layers and their interactions with rough topography. Using a hierarchy of progressively idealized simulations, I identify three physical processes that set the stratification of abyssal mixing layers (in addition to the weak buoyancy-driven cross-slope circulation): submesoscale baroclinic eddies on the ridge flanks, enhanced up-canyon flow due to inhibition of the cross-canyon thermal wind, and homogenization of canyon troughs below the level of blocking sills. Combined, these processes maintain a sufficiently large near-boundary stratification for mixing to drive globally significant BBL upwelling. In Chapter 3, simulated Tracer Release Experiments illustrate how passive tracers are mixed, stirred, and advected in abyssal mixing layers. Exact diagnostics reveal that while a tracer’s diapycnal motion is directly proportional to the mean divergence of mixing rates, its diapycnal spreading depends on both the mean mixing rate and an additional non-linear stretching term. These simulations suggest that the theorized boundary-layer control on the abyssal circulation is falsifiable: downwelling in the SML has already been confirmed by the Brazil Basin Tracer Release Experiment, while an upcoming experiment in the Rockall Trough will confirm or deny the existence of upwelling in the BBL.

Description: This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 174530. I also acknowledge funding support from National Science Foundation Awards OCE-1536515 and OCE-1736109. This work was partially supported by MIT’s Rosenblith Presidential Fellowship.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biological Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Sound is utilized by marine animal taxa for many ecologically important functions, and these taxa are vulnerable to adverse effects of anthropogenic noise on hearing and behavior. However, little is known about marine invertebrates’ responses to anthropogenic noise, and the ambient environmental sounds (“soundscapes”) they detect and respond to. Most acoustic studies report sound pressure (detected by mammals and some fish), but few report particle motion, the back-and-forth vibratory component of sound detected by marine invertebrates. I investigated invertebrate use of and response to sounds in two facets: 1) behavioral responses of longfin squid, Doryteuthis pealeii to anthropogenic noise, and 2) particle motion of coral reef soundscapes in the U.S. Virgin Islands. In laboratory-based experiments I exposed D. pealeii to construction noise originally recorded from an offshore wind farm. I found significant increases in squids’ alarm responses and in failed prey capture attempts during noise. Conversely, noise exposure had no significant effects on reproductive behaviors of groups of D. pealeii, indicating high motivation of these squid to reproduce during this stressor. Collectively, these experiments revealed the importance of considering behavioral context in studies and regulatory decisions regarding invertebrates’ susceptibility to anthropogenic noise impacts. In studying coral reef soundscapes, I reported particle motion trends over several months for coral reefs varying in habitat quality, including coral cover and fish abundance. I found acoustic properties over which particle motion closely scaled with pressure, and others over which it did not. I compared soundscape data with particle motion hearing thresholds, and found that invertebrates may only detect high amplitude and low frequency transient sound cues on reefs, such as those produced by fishes. My research bring new insights on natural and anthropogenic sound cues detectable by marine invertebrates, and how and when invertebrates will be vulnerable to anthropogenic noise pollution.

Description: My graduate work was funded in part by the US Department of Interior, Bureau of Ocean Energy Management Environmental Studies Program through Interagency Agreement Number M17PG00029 with the U.S. Department of Commerce, National Oceanic and Atmospheric Administration (funding to Aran Mooney and Jenni Stanley). My work was also supported by the NSF Biological Oceanography award OCE-1536782 (funding to Aran Mooney). I received tuition and stipend support from the National Science Foundation Graduate Research Fellowship Program [Grant No. 2388357]. The Academic Program Office at the Woods Hole Oceanographic Institution provided tuition and stipend support as well as travel support. The MIT Student Assistance Fund, the Aquatic Noise 2019 Organizing Committee, and the Acoustical Society of America also provided travel support.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: A novel performance metric to improve underwater digital acoustic communication, called Multipath Penalty (MPP), is proposed as an alternative to traditional signal-to-noise ratio (SNR) methods in the context of the Arctic Beaufort Sea. MPP and SNR are compared alongside a third performance metric, Minimum Achievable Error (MAE), which replicates the operation of a channel estimate-based decision feedback equalizer in an acoustic modem. The three metrics are then tested in a hardware-in-the-loop Virtual Ocean simulator for an autonomous undersea vehicle (AUV) communicating with a collaborator. Using field data of modem statistics obtained duringICEX20 and expanded data supplied by the simulator, calibration of the three metrics to modem packet success is evaluated, resulting in a proposed recalibration for MAE. The AUV’s ability to communicate when adaptively choosing its depth is analyzed above and below the Beaufort Lens, and settings for MPP’s engineering variables are obtained. The results show MPP generally improves reception and demodulation of acoustic transmissions over SNR by approximately 5% within an operational range of 8 km, while achieving similar results to the more robust metric MAE. MPP is an improved utility for underwater digital acoustic communication in both marine autonomy and as a tactical decision aid.

Description: This work would not be possible without the extraordinary support of the United States Navy, which provided funding for this research, my degree, and my livelihood as an active duty submarine officer.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: There are many significant challenges for unmanned autonomous platforms at sea including predicting the likely scenarios for the ocean environment, quantifying regional uncertainties, and updating forecasts of the evolving dynamics using their observations. Due to the operational constraints such as onboard power, memory, bandwidth, and space limitations, efficient adaptive reduced order models (ROMs) are needed for onboard predictions. In the first part, several reduced order modeling schemes for regional ocean forecasting onboard autonomous platforms at sea are described, investigated, and evaluated. We find that Dynamic Mode Decomposition (DMD), a data-driven dimensionality reduction algorithm, can be used for accurate predictions for short periods in ocean environments. We evaluate DMD methods for ocean PE simulations by comparing and testing several schemes including domain splitting, adjusting training size, and utilizing 3D inputs. Three new approaches that combine uncertainty with DMD are also investigated and found to produce practical and accurate results, especially if we employ either an ensemble of DMD forecasts or the DMD of an ensemble of forecasts. We also demonstrate some results from projecting / compressing high-fidelity forecasts using schemes such as POD projection and K-SVD for sparse representation due to showing promise for distributing forecasts efficiently to remote vehicles. In the second part, we combine DMD methods with the GMM-DO filter to produce DMD forecasts with Bayesian data assimilation that can quickly and efficiently be computed onboard an autonomous platform. We compare the accuracy of our results to traditional DMD forecasts and DMD with Ensemble Kalman Filter (EnKF) forecast results and show that in Root Mean Square Error (RMSE) sense as well as error field sense, that the DMD with GMM-DO errors are smaller and the errors grow slower in time than the other mentioned schemes. We also showcase the DMD of the ensemble method with GMM-DO. We conclude that due to its accurate and computationally efficient results, it could be readily applied onboard autonomous platforms. Overall, our contributions developed and integrated stochastic DMD forecasts and efficient Bayesian GMM-DO updates of the DMD state and parameters, learning from the limited gappy observation data sets.

Description: I wish to thank the U.S. Navy’s Civilian Institution Program along with the MITWHOI Joint Program for providing the funding and resources that made this research and continuing my education possible.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: The Beaufort Gyre region of the Arctic Ocean is strongly stratified at the base of the wintertime mixed layer, which impedes the vertical transport of heat, energy, and other tracers. Ice-Tethered Profiler observations during 2004-2018 were used to characterize and investigate the seasonal and interannual variability of the strength, depth, density, and thickness of this highly stratified layer at the base of the mixed layer. This includes investigating the remnant stratification maximum, which formed when the summer mixed layer shoaled. Seasonally, the stratification maximum was never in a steady state. It was largest in October (4.8 × 10−3 rad2/sec2) and decreased during all winter months (to 2.3 × 10−3rad2/sec2 in June), indicating that surface forcing and interior vertical mixing were never in equilibrium during the year. Interannually, the period from 2011-2018 had a higher stratification maximum than then the period from 2005-2010 regardless of the season. The remnant stratification maximum was consistently weaker than the winter stratification maximum from which it formed. The initial evolution of the remnant stratification maximum is used to estimate an effective vertical diffusivity of order 10−6m2/s. No significant geographic variability was found, in part due to high temporal and small scale variability of the stratification maximum layer. Implications for heat transport through to the sea ice cover are discussed.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biological Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2022.

Description: Protists are taxonomically and metabolically diverse drivers of energy and nutrient flow in the marine environment, with recent research suggesting significant roles in global carbon cycling throughout the water column. Top-down controls on planktonic protists include grazing and parasitism, processes that both contribute to nutrient transfer and biogeochemical cycling in the global ocean. Recent global surveys of eukaryotic small subunit ribosomal RNA molecular signatures have highlighted the fact that parasites belonging to the marine alveolate order Syndiniales are both abundant and ubiquitous in coastal and open ocean environments, suggesting a major role for this taxon in marine food webs. Two coastal sites, Saanich Inlet (Vancouver Island, BC) and Salt Pond (Falmouth, MA, USA) were selected as model ecosystems to examine the impacts of Syndinian parasitism on protist communities. Data presented in this thesis combines high-resolution sampling, water chemistry (including nutrients) analyses, molecular marker gene analyses, fluorescence in situ hybridization, and modeling to address key knowledge gaps regarding syndinian ecology. Information is presented on previously undescribed putative host taxa, the prevalence of syndinian parasites and infections on different hosts in coastal waters, and a framework for modeling host-parasite interactions based on field observations.

Description: Research was supported by the WHOI Ocean Venture Fund, the National Science Foundation Biological Oceanography OCE-1851012, and the National Science Foundation Graduate Research Fellowship under Grant No. 1745302.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2022.

Description: The ventilation of intermediate waters in the Labrador Sea has important implications for the strength of the Atlantic Meridional Overturning Circulation. Boundary current-interior interactions regulate the exchange of properties between the slope and the basin, which in turn regulates the magnitude of interior convection and the export of ventilated waters from the subpolar gyre. This thesis characterizes theWest Greenland Boundary Current System near Cape Farewell across a range of spatio-temporal scales. The boundary current system is composed of three velocity cores: (1) the West Greenland Coastal Current (WGCC), transporting Greenland and Arctic meltwaters on the shelf; (2) the West Greenland Current (WGC), which advects warm, saline Atlantic-origin water at depth, meltwaters at the surface, and newly-ventilated Labrador Sea Water (LSW); and (3) the Deep Western Boundary Current, which carries dense overflow waters ventilated in the Nordic Seas. The seasonal presence of the LSW and Atlantic-origin water are dictated by air-sea buoyancy forcing, while the seasonality of the WGCC is governed by remote wind forcing and the propagation of coastally trapped waves from East Greenland. Using mooring data and hydrographic surveys, we demonstrate mid-depth intensified cyclones generated at Denmark Strait are found offshore of the WGC and enhance the overflow water transport at synoptic timescales. Using mooring, hydrographic, and satellite data, we demonstrate that the WGC undergoes extensive meandering due to baroclinic instability that is enhanced in winter due to LSW formation adjacent to the current. This leads to the production of small-scale, anticyclonic eddies that can account for the entirety of wintertime heat loss within the Labrador Sea. The meanders are shown to trigger the formation of Irminger Rings downstream. Using mooring, hydrographic, atmospheric, and Lagrangian data, and a mixing model, we find that strong atmospheric storms known as forward tip jets cause upwelling at the shelfbreak that triggers offshore export of freshwater. This freshwater flux can explain the observed lack of ventilation in the eastern Labrador Sea. Together, this thesis documents previously unobserved interannual, seasonal, and synoptic-scale variability and dynamics within the West Greenland boundary current system that must be accounted for in future modeling.

Description: The work in this dissertation was funded by the National Science Foundation grants OCE-1259618 and OCE-1756361.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Chemical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Arctic marine and lacustrine systems are experiencing rapid warming due to climate change. These changes are especially important at the interface between sediments and surface waters because they are hotspots for biogeochemical transformations such as redox reactions, nutrient consumption and regeneration, organic matter leaching and degradation, and mineral weathering. Radium isotopes (223Ra, 224Ra, 226Ra, 228Ra) and radon-222, naturally occurring radioactive isotopes produced in sediments, are well-suited as tracers of nutrients, trace metals, and organic matter cycling processes at the sediment-water interface. In this thesis, I have applied radon-222 and the quartet of radium isotopes to study fundamental processes in subarctic lakes and on the Arctic continental shelf. First, radon-222 is used to quantify groundwater discharge into a shallow, tundra lake on the Yukon-Kuskokwim Delta in Alaska in summer of 2017. Radon-derived groundwater fluxes were then paired with methane (CH4) measurements to determine delivery rates of methane into the lake via groundwater. Groundwater CH4 fluxes significantly exceeded diffusive air-water fluxes from the lake to the atmosphere, suggesting that groundwater is an important source of CH4 to Arctic lakes and may drive observed CH4 emissions. Higher CH4 emissions were observed compared to those reported previously in high latitude lakes, like due to higher CH4 concentrations in groundwater. These findings indicate that deltaic lakes across warmer permafrost regions may act as important hotspots for methane release across Arctic landscapes. Then, the quartet of radium isotopes is used to study the impacts of storms and sea ice formation as drivers of sediment-water interaction on the Alaskan Beaufort shelf. The timeseries presented in this study is among the first to document the combined physical and chemical signals of winter water formation in the Beaufort Sea, made possible by repeat occupations of the central Beaufort shelf. Radium measurements are combined with inorganic nitrogen and hydrographic measurements to elucidate the episodic behavior of winter water formation and its ability to drive exchange with bottom sediments during freeze-up.

Description: Financial support for Chapter 2 was funded by National Science Foundation awards OCE-1458305 to M.A.C., 1561437 to S.M.N, J.D.S., and R.M.H and 1624927 to S.M.N., P.J.M. and R.M.H. The work completed for Chapter 3 was funded by the Montrym Fund at the Massachusetts Institute of Technology, the Academic Programs Office at Woods Hole Oceanographic Institution, and the NSF Arctic GEOTRACES (OCE-1458305), Pacific GEOTRACES (OCE-1736277), and Arctic Observing Network programs (OPP-1733564).

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: Robotic swarms are increasingly complex above the waterline due to reliable communication links. However, the limited propagation of similar signals in the ocean has impacted advances in undersea robotics. Underwater vehicles often rely on acoustics for navigation solutions; however, this presents challenges for robotic swarms. Many localization methods rely on precision time synchronization or two-way communication to estimate ranges. The cost of Chip-scale Atomic Clocks (CSACs) and acoustic modems is limiting for large-scale swarms due to the cost-per-vehicle and communications structure. We propose a single vehicle with reliable navigation as a "leader" for a scalable swarm of lower-cost vehicles that receive signals via a single hydrophone. This thesis outlines range estimation methods for sources with known signal content, including frequency and power at its origin. Transmission loss is calculated based on sound absorption in seawater and geometric spreading loss to estimate range through the Signal Absorption-Based Range Estimator (SABRE). SABRE's objective is to address techniques that support low-cost undersea swarming. This thesis's contributions include a novel method for range estimation onboard underwater vehicles that supports relative navigation through Doppler-shift methods for target bearing. This thesis develops the theory, algorithms, and analytical tools for real-world data range estimation.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.

Description: This thesis examines the transition of a vessel from the open ocean, where collisions are rare, to a high risk and heavy traffic area such as a Traffic Separation Scheme (TSS). Previous autonomy approaches generally view path planning and collision avoidance as two separate functions, i.e. a vessel will follow the planned path until conditions are met for collision avoidance algorithms to take over. Here an intermediate phase is proposed with the goal of adjusting the time of arrival to a high vessel density area so that the risk of collision is reduced. A general algorithm that calculates maximum future traffic density for all choices in the speed domain is proposed and implemented as a MOOS-IvP behavior. This behavior gives the vessel awareness of future collision risks and aids the collision avoidance process. This new approach improves the safety of the vessel by reducing the number of risky encounters that will likely require the vessel to maneuver for safety.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: The early life stages of marine fishes play a critical role in population dynamics, largely due to their high abundance, high mortality, and ease of transport in ocean currents. This dissertation demonstrates the value of combining larval data, collected in the field and the laboratory, with model simulations. In Chapter 2, analyses of field observations of ontogenetic vertical distributions of coral reef fish revealed a diversity of behaviors both between and within families. In Caribbean-wide particle-tracking simulations of representative behaviors, surface-dwelling larvae were generally transported longer distances with greater population connectivity amongst habitat patches, while the evenly-distributed vertical behavior and downward ontogenetic vertical migration were similar to one another and led to greater retention near natal sites. However, hydrodynamics and habitat vailability created some local patterns that contradicted the overall expectation. Chapter 3 presents evidence of tuna spawning inside a large no-take marine protected area, the Phoenix Islands Protected Area (PIPA). Despite variation in temperature and chlorophyll, the larval tuna distributions were similar amongst years, with skipjack (Katsuwonus pelamis) and Thunnus spp. tunas observed in all three years. Backtracking simulations indicated that spawning occurred inside PIPA in all 3 study years, demonstrating that PIPA is protecting viable tuna spawning habitat. In Chapter 4, several lines of larval evidence support the classification of the Slope Sea as a major spawning ground for Atlantic bluefin tuna with conditions suitable for larval growth. The abundance of bluefin tuna larvae observed in the Slope Sea aligns with typical observations on the other two spawning grounds. Age and growth analyses of bluefin tuna larvae collected in the Slope Sea and the Gulf of Mexico in 2016 did not show a growth rate difference between regions, but did suggest that Slope Sea larvae are larger at the onset of exogenous feeding. Collected larvae were backtracked to locations north of Cape Hatteras and forward tracked to show that they would have been retained within the Slope Sea until the onset of swimming. As a whole, this thesis presents valuable contributions to the study of larval fishes and the attendant implications for marine resource management.

Description: National Science Foundation Graduate Research Fellowship Program (to C.M.H.), the Woods Hole Oceanographic Institution Ocean Life Institute (Grant 22569.01 to J. Llopiz and C.M.H.), the Adelaide and Charles Link Foundation, the Phoenix Islands Protected Area Trust, the J. Seward Johnson Endowment in support of the Woods Hole Oceanographic Institution's Marine Policy Center, and the WHOI Academic Programs Office.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: Subduction zones host the greatest earthquakes on earth and pose great threat to human society. The largest slip in megathrust earthquakes often occurs in the 10–50 km depth range, yet seismic imaging of the material properties in this region has proven difficult. This thesis focuses on developing methods to utilize high frequency (2–12 Hz) seismic waves scattered from the megathrust plate interface to constrain its fine-scale velocity structures and to investigate the relationship between velocity structures and megathrust slip behaviors. Chapter 2 investigates the locking condition of the subducted Gorda plate by simulating afterslip that would be expected as a result of the stress changes from offshore strike-slip earthquakes. Chapter 3 develops array analysis methods to identify P-to-S and S-to-P seismic converted phases that convert at the subducted Gorda plate interface from local earthquakes and uses them to constrain the geometry and material properties of the plate boundary fault of the subducted Gorda plate between 5–20 km depth. Chapters 4 and 5 use a dense nodal array and numerical modeling methods to study the seismic guided waves that propagate along the thin low velocity layer at the boundary of the subducted Gorda plate. Taken together, our results indicate that material properties of the subduction plateboundary fault is highly heterogeneous and the plate-boundary fault is potentially contained in a low velocity layer with significant porosity and fluid content at seismogenic depths.

Description: Funding for this research was provided by National Science Foundation Division of Earth Sciences (EAR) award #1520690 and the WHOI Academic Programs Office.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: Anthropogenic emissions of greenhouse gases are driving rapid changes in ocean conditions. Shallow-water coral reefs are experiencing the brunt of these changes, including intensifying marine heatwaves (MHWs) and rapid ocean acidification (OA). Consequently, coral reefs are in broad-scale decline, threatening the livelihoods of hundreds of millions of people. Ensuring survival of coral reefs in the 21st century will thus require a new management approach that incorporates robust understanding of reef-scale climate change, the mechanisms by which these changes impact corals, and their potential for adaptation. In this thesis, I extract information from within coral skeletons to 1) Quantify the climate changes occurring on coral reefs and the effects on coral growth, 2) Identify differences in the sensitivity of coral reefs to these changes, and 3) Evaluate the adaptation potential of the keystone reef-building coral, Porites. First, I develop a mechanistic Porites growth model and reveal the physicochemical link between OA and skeletal formation. I show that the thickening (densification) of coral skeletal framework is most vulnerable to OA and that, under 21st century climate model projections, OA will reduce Porites skeletal density globally, with greatest impact in the Coral Triangle. Second, I develop an improved metric of thermal stress, and use a skeletal bleaching proxy to quantify coral responses to intensifying heatwaves in the central equatorial Pacific (CEP) since 1982. My work reveals a long history of bleaching in the CEP, and reef-specific differences in thermal tolerance linked to past heatwave exposure implying that, over time, reef communities have adapted to tolerate their unique thermal regimes. Third, I refine the Sr-U paleo-thermometer to enable monthly-resolved sea surface temperatures (SST) generation using laser ablation ICPMS. I show that laser Sr-U accurately captures CEP SST, including the frequency and amplitude of MHWs. Finally, I apply laser Sr-U to reconstruct the past 100 years of SST at Jarvis Island in the CEP, and evaluate my proxy record of bleaching severity in this context. I determine that Porites coral populations on Jarvis Island have not yet adapted to the pace of anthropogenic climate change.

Description: This research was supported by US National Science Foundation Awards OCE-1220529, ANT-1246387, OCE-1737311, CE-1601365, OCE-1805618, OCE-1537338, OCE-2016133, and from the Woods Hole Oceanographic Institution through the Ocean Life Institute, the Ocean Ventures Fund, the Grassle Fellowship Fund, and the MIT-WHOI Academic Programs Office. Additional funding was provided by the Taiwan MOST Grant 104-2628-M-001-007-MY3, the Robertson Foundation, the Leverhulme Trust in UK, the Atlantic Donor Advised Fund, The Prince Albert 2 of Monaco Foundation, the Akiko Shiraki Dynner Fund, the New England Aquarium, the Martin Family Society Fellowship for Sustainability, the Gates Millenium Scholarship, the Arthur Vining Davis Foundation, the NOAA Coral Reef Conservation Program, and from the Woods Hole Oceanographic Institution through Investment in Science Fund, the Early Career Award, and the Access to the Sea Award.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical and Oceanographic Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: The satellite ocean color remote sensing paradigm developed by government space agencies enables the assessment of ocean color products on global scales at kilometer resolutions. A similar paradigm has not yet been developed for regional scales at sub-meter resolutions, but it is essential for specific ocean color applications (e.g., mapping algal biomass in the marginal ice zone). While many aspects of the satellite ocean color remote sensing paradigm are applicable to sub-meter scales, steps within the paradigm must be adapted to the optical character of the ocean at these scales and the opto-electronics of the available sensing instruments. This dissertation adapts the three steps of the satellite ocean color remote sensing paradigm that benefit the most from reassessment at sub-meter scales, namely the correction for surface-reflected light, the design and selection of the opto-electronics and the post-processing of over-sampled regions. First, I identify which surface-reflected light removal algorithm and view angle combination are optimal at sub-meter scales, using data collected during a field deployment to the Martha’s Vineyard Coastal Observatory. I find that of the three most widely used glint correction algorithms, a spectral optimization based approach applied to measurements with a 40∘ view angle best recovers the remotesensing reflectance and chlorophyll concentration despite centimeter scale variability in the surface-reflected light. Second, I develop a simulation framework to assess the impact of higher optical and electronics noise on ocean color product retrieval from unique ocean color scenarios. I demonstrate the framework’s power as a design tool by identifying hardware limitations, and developing potential solutions, for estimating algal biomass from high dynamic range sensing in the marginal ice zone. Third, I investigate a spectral super-resolution technique for application to spatially over-sampled oceanic regions. I determine that this technique more accurately represents spectral frequencies beyond the Nyquist and that it can be trained to be invariant to noise sources characteristic of ocean color remote sensing on images with similar statistics as the training dataset. Overall, the developed and critically assessed sub-meter ocean color remote sensing paradigm enables researchers to collect high fidelity sub-meter data from imaging spectrometers in unique ocean color scenarios.

Description: Ryan O’Shea was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program. This research was funded by Woods Hole Oceanographic Institution’s Edwin W. Hiam Ocean Science and Technology Award Fund, its Ocean Venture Funds, its Academic Programs Office, and the National Aeronautics and Space Administration via grant number CCE NNX17AI72G to Dr. Samuel Laney. The raw data for Figures 3-3 and 3-4 were provided through Australian Antarctic Science grants 2678 and 4390.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Physical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2021.

Description: Estimating turbulence in the marine-atmospheric boundary layer is critical to many industrial, commercial and scientific fields, but of particular importance to the wind energy industry. Contributing to both the efficiency of energy extraction and the life-cycle cost of the turbine itself, turbulence in the atmospheric boundary layer is estimated within the wind energy industry as Turbulence Intensity (TI) and more recently by Turbulent Kinetic Energy (TKE). Traditional in-situ methods to measure turbulence are extremely difficult to deploy in the marine environment, resulting in a recent movement to and dependence on remote sensing methods. One type of remote sensing instrument, Doppler lidars, have shown to reliably estimate the wind speed and atmospheric turbulence while being cost effective and easily deployable, and hence are being increasingly utilized as a standard for wind energy assessments. In this thesis, the ability of lidars to measure turbulence up to a height of 200 m above mean sea level in the marine-atmospheric boundary layer was tested using a 7-month data set spanning winter to early summer. Lidar-based TI and TKE were estimated by three methods using observations from a highly validated lidar system and compared under both convective and stable atmospheric stability conditions. Convective periods were found to have higher turbulence at all the heights compared to stable conditions, while mean wind speed and shear were higher during stable conditions. The study period was characterized by generally low turbulent conditions with high turbulence events occurring at timescales of a few days. Mean vertical profiles of TKE were non-uniformly distributed in height during low turbulent conditions. During highly turbulent events, TKE increased more strongly with height. The definition of TI– following the industry or meteorology conventions – had no real effect on the results, and differences between cup or sonic anemometers and lidar TI values were small except at low wind speeds. All the three lidar-based TKE methods tested corresponded closely to independent estimates, and differences between the methods were small relative to the temporal variability of TKE observed at the offshore site.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2021.

Description: The apparent global increase in harmful algal blooms (HABs) includes Pseudo-nitzschia blooms in the Gulf of Maine, where shellfishery closures can cost millions of dollars. Temperatures in the gulf are warming, which can affect the severity of some HABs. Yet Pseudo-nitzschia in the region are understudied. Pseudo-nitzschia bloom dynamics, P. australis introduction, and potential future changes thereof were investigated in the Gulf of Maine. Data from ship surveys and moorings were used, as well as hydrodynamic, climate, and Lagrangian particle tracking models. Pseudonitzschia bloom toxicity was driven primarily by species composition, not environmental factors. P. australis was introduced to the region in 2016 via a coastal current from the Scotian Shelf. Climate change might intensify Pseudo-nitzschia blooms, shift bloom timing 1–2 weeks earlier in the spring or 4–6 weeks later in the fall, or lengthen the growing season by 3 weeks. It might also affect species composition and connectivity within the gulf. This work has implications for the monitoring of current and future blooms in the Gulf of Maine and for our understanding of HAB introduction to the region. It can also be used to develop predictive models for Pseudo-nitzschia, which could be applied to other HABs.

Description: This research was funded by the National Science Foundation (Grants OCE-1314642 and OCE-1840381), the National Institute of Environmental Health Sciences (Grants 1P01ES021923-01 and P01 ES028938-01), the Woods Hole Center for Oceans and Human Health, WHOI Academic Programs Funds, the Vannevar Bush Faculty Fellowship, and the National Oceanic and Atmospheric Administration’s HAB Event Response Program (2012 and 2016).

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2021.

Description: The Arctic Ocean is a vital component of Earth’s climate system experiencing dramatic environmental changes. The changes are reflected in its underwater ambient soundscape as its origin and propagation are primarily dependent on properties of the ice cover and water column. The first component of this work examines the effect on ambient noise characteristics due to changes to the Beaufort Sea sound speed profile (SSP) and ice cover. Specifically, the emergence of a warm water intrusion near 70 m depth has altered the historical Arctic SSP while the ice cover has become thinner and younger due to the rise in average global temperature. Hypothesized shifts to the ambient soundscape and surface noise generation due to these changes are verified by comparing the measured noise data during two experiments to modeled results. These changes include a broadside notch in noise vertical directionality as well as a shift from uniform surface noise generation to discrete generation at specific ranges. Motivated by our data analyses, the second component presents several tools to facilitate ambient noise characterization and generation monitoring. One is a convolutional neural network (CNN) approach to noise range estimation. Its robustness to SSP and bottom depth mismatch is compared with conventional matched field processing. We further explore how the CNN approach achieves its performance by examining its intermediate outputs. Another tool is a frequency domain, transient event detection algorithm that leverages image processing and hierarchical clustering to identify and categorize noise transients in data spectrograms. The spectral content retained by this method enables insight into the generation mechanism of the detected events by the ice cover. Lastly, we present the deployment of a seismo-acoustic system to localize transient events. Two forward approaches that utilize time-difference-ofarrival are described and compared with a more conventional, inverse technique. The examination of this system’s performance prompts recommendations for future deployments. With our ambient noise analysis and algorithm development, we hope these contributions provide a stronger foundation for continued study of the Arctic ambient soundscape as the region continues to grow in significance.

Description: Office of Naval Research (ONR) via the University of California - San Diego (UCSD) under award number N00014-16-1-2129. Defense Advanced Research Projects Agency (DARPA) via Applied Physical Sciences Corp. (APS) under award number HR0011-18-C-0008. Office of Naval Research (ONR) under award number N00014-17-1-2474. Office of Naval Research (ONR) under award number N00014-19-1-2741. National Science Foundation (NSF) under grant number 2389237.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Oceanographic Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2021.

Description: Nearly 1.5 million people inhabit barrier islands along the U.S. Atlantic and Gulf Coasts and coastal groundwater dynamics influence the availability of freshwater, ecosystem health, pollutant transport, and flooding in these densely populated communities. However, groundwater dynamics, including the aquifer head distribution and subsurface salinity structure, in coastal aquifers are affected by multiple environmental forcings, such as waves, tides, storm surges, and precipitation that act on a variety of spatial and temporal scales, making coastal groundwater dynamics complex and difficult to predict. Here, measurements of groundwater heads, salinities, and temperatures collected for 3 years across a 550-m-wide barrier island are used in conjunction with observations of ocean tides, surge, waves, sound level, and rainfall to characterize the dynamics of the surface aquifer. Infiltration from surge, tides, and waves during storms caused up to 2 m increases in the groundwater level under the dune. The head gradients owing to these storm-induced groundwater bulges suggest flows become inland directed on the ocean-side of the island during storms. An upper saline plume (20-30 PSU) was observed above fresher (10 PSU) water up to 30 m inland of the dune face, which was the maximum wave runup location. Differences in inland propagation between tidal- and storm-induced groundwater head fluctuations are explained using analytical theories for intermediate depth aquifers. Additionally, a separate analytical water-table evolution model driven with estimated ocean shoreline water levels (based on the 36-hr-averaged offshore tide, surge, and wave height) and measured precipitation is validated by citizen-science flood reports and predicts the maximum water-table height within 0.1 m of the observed levels across the barrier island.

Description: Funding for this research was provided by the U.S. Coastal Research Program, the National Science Foundation, a National Science Foundation Graduate Research Fellowship, the Woods Hole Oceanographic ISP program, and National Security Science & Engineering and Vannevar Bush Faculty Fellowships.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Autonomous underwater vehicles (AUVs) are an increasingly capable robotic platform, with embedded acoustic sensing to facilitate navigation, communication, and collaboration. The global positioning system (GPS), ubiquitous for air- and terrestrial-based drones, cannot position a submerged AUV. Current methods for acoustic underwater navigation employ a deterministic sound speed to convert recorded travel time into range. In acoustically complex propagation environments, however, accurate navigation is predicated on how the sound speed structure affects propagation. The Arctic’s Beaufort Gyre provides an excellent case study for this relationship via the Beaufort Lens, a recently observed influx of warm Pacific water that forms a widespread yet variable sound speed lens throughout the gyre. At short ranges, the lens intensifies multipath propagation and creates a dramatic shadow zone, deteriorating acoustic communication and navigation performance. The Arctic also poses the additional operational challenge of an ice-covered, GPSdenied environment. This dissertation demonstrates a framework for a physics-based, model-aided, real-time conversion of recorded travel time into range—the first of its kind—which was essential to the successful AUV deployment and recovery in the Beaufort Sea, in March 2020. There are three nominal steps. First, we investigate the spatio-temporal variability of the Beaufort Lens. Second, we design a human-in-the-loop graphical decision-making framework to encode desired sound speed profile information into a lightweight, digital acoustic message for onboard navigation and communication. Lastly, we embed a stochastic, ray-based prediction of the group velocity as a function of extrapolated source and receiver locations. This framework is further validated by transmissions among GPS-aided modem buoys and improved upon to rival GPS accuracy and surpass GPS precision. The Arctic is one of the most sensitive regions to climate change, and as warmer surface temperatures and shrinking sea ice extent continue to deviate from historical conditions, the region will become more accessible and navigable. Underwater robotic platforms to monitor these environmental changes, along with the inevitable rise in human traffic related to trade, fishing, tourism, and military activity, are paramount to coupling national security with international climate security.

Description: Office of Naval Research (N00014-14-1-0214) — GOATS’14 Adaptive and Collaborative Exploitation of 3-Dimensional Environmental Acoustics in Distributed Undersea Networks Draper Laboratory Incorporated (SC001-0000001039) — Positioning System for Deep Ocean Navigation (POSYDON) Office of Naval Research (N00014-16-1-2129) — MURI: The Information Content of Ocean Noise: Theory and Experiment Office of Naval Research (N00014-17-1-2474) — Environmentally Adaptive Acoustic Communication and Navigation in the New Arctic Office of Naval Research (N00014-19-1-2716) — TFO: Assessing Realism and Uncertainties in Navy Decision Aids Department of Defense, Office of Naval Research — National Defense, Science, and Engineering Graduate Fellowship

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Aeronautics and Astronautics at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2021.

Description: Global temperature rise and increased atmospheric carbon dioxide (CO2) levels have affected the health of the world’s ocean and water ecosystems, impacting the balances of natural carbon cycling and causing ocean acidification. Additionally, as global temperatures rise, thawing permafrost has stimulated increased release of methane (CH4), a gas with a shorter lifetime in the atmosphere but with even more heat trapping ability than CO2. In situ analysis of dissolved gas content in surface waters is currently performed with large, expensive instruments, such as spectrometers, which are coupled with gas equilibration systems, which extract dissolved gas from water and feed it to the sensor. Accurate, low cost, and portable sensors are needed to measure the dissolved CH4 and CO2 concentration in water systems to quantify their release and understand their relationship to the global carbon budget. At the same time, while greenhouse gases are well established threats to water ecosystems, the ubiquity and potential consequences of microplastics in aqueous environments are just beginning to be recognized by the environmental research community. Microplastics (MPs) are small particles of polymer debris, commonly defined as being between 1 μm and 1000 μm. Despite the pervasiveness of MPs, our ability to characterize MPs in the environment is limited by the lack of technologies for rapidly and accurately identifying and quantifying MPs. This thesis is concerned with the engineering challenges prompted by the need for high quality and quantity environmental data to better study and the impact, cycling, and prevalence of these pollutants in aqueous environments. Three distinct investigations are presented here. First, the design of the Low-Cost Gas Extraction and Measurement System (LC-GEMS) for dissolved CO2 is presented. At just under $600 dollar to build, the LC-GEMS is an ultra-portable, toolbox-sized instrument for dissolved gas sensing in near-surface waters. The LCGEMS was characterized in the lab and demonstrated linear relationships with dissolved CO2 as well as temperature. Lab calibrations and subsequent field testing in the Little Sippewissett Marsh, in Falmouth, Massachusetts showed that the LCGEMS captures both diurnal and minute-time scale trends in dissolved CO2. Second, this thesis presents the novel design of three simple and low-cost planar nanophotonic and plasmonic structures as optical transducers for measuring dissolved CH4. Through simulations, the sensitivity of the structures are evaluated and found to exhibit superior performance in the reflectance intensity readout mode to that of the standard surface-plasmon-polariton-mode Spreeta sensor. A practical, small, and low-cost implementation of this chip with a simple intensity-based measurement scheme is proposed. This design is novel in the space of dissolved gas monitoring because it shows potential to measure directly in the water phase while being robust and low-cost to implement. Finally, this thesis presents a literature review and perspective to motivate the development of field-deployable microplastic sensing techniques. A framework for field-deployable microplastic sensing is presented and seeks to inform the MP community of the potential in both traditional MP analysis techniques and unconventional methods for creating rapid and automated MP sensors. The field-deployabilty framework addresses a full scope of practical/technological trade-offs to be considered for portable MP detection.

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: As the western boundary current of the North Atlantic, the Gulf Stream is a well established area of interest for the United States Navy, predominately due to its proximity to the continental shelf and the associated challenges of acoustic propagation across large property gradients. Autonomous underwater gliders conduct routine, high-resolution surveys along the U.S. East Coast, including within the Gulf Stream. These observations are assimilated into the operational Navy Coastal Ocean Model (NCOM). An investigation of the forecast-to-nowcast changes in the model for 2017 demonstrates the impact of the observations on the model. The magnitude of model change as a function of distance from nearest new observation reveals relatively large impact of glider observations within a radius of 𝒪(100) km. Glider observations are associated with larger local impact than Argo data, likely due to glider sampling focusing on large spatial gradients. Due to the advective nature of the Gulf Stream system, the impact of glider observations in the model is anisotropic with larger impacts extending downstream from observation locations. Forecast-to-nowcast changes in modeled temperature, salinity, and density result in improved agreement between observed and modeled ocean structure within the upper 200 m over the 24 hours between successive model runs.

Description: This research was funded via the United States Navy’s Civilian Institution Program with the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program (MIT/WHOI JP). Glider observations and analyses have been generously supported by the National Science Foundation (OCE-0220769, OCE-1558521, OCE-1633911, OCE-1923362), NOAA’s Global Ocean Monitoring and Observing Program (NA14OAR4320158, NA19OAR4320074), the Office of Naval Research (N000141713040), Eastman Chemical Corporation, WHOI’s Oceans and Climate Change Institute, and the W. Van Alan Clark, Jr. Chair for Excellence in Oceanography at WHOI (awarded to Breck Owens).

Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: This thesis analyzes data from two types of unique drifter experiments in order to characterize two aspects of ocean flows that are often difficult to study. First, vertical velocities and their associated transport processes are often challenging to observe in the real ocean since vertical velocities are typically orders of magnitude smaller than horizontal velocities in mesoscale and submesoscale flows. Second, Lagrangian coherent structures (LCS) are features which categorize ocean flows into regimes of distinct behavior. These structures are also difficult to quantify in the real ocean, since sets of gridded trajectories from real ocean data (rather than model fields) are rarely available. The first experiment uses drifters drogued at multiple depths in the Alboran Sea to observe and characterize the ocean’s vertical structure, particularly near a strong front where vertical velocities are expected to be much stronger than other regions of the Ocean. The second experiment uses a roughly gridded pattern of surface drifters in the Gulf of Mexico to study LCSs as quantified by methods from dynamical systems such as finitetime Lyapunov exponents (FTLEs), trajectory arc-length, correlation dimension, dilation, Lagrangian-averaged vorticity deviation (LAVD), and spectral clustering. This thesis includes the first attempt to apply these dynamical systems techniques to real drifters for LCS detection. Overall, these experiments and the methods used in this paper are shown to be promising new techniques for quantifying both the vertical structure of ocean flows and Lagrangian Coherent Structures of flows using real drifter data. Future work may involve modified versions of the experiments, with denser sets of ocean drifters in the horizontal and/or vertical directions.

Description: My Masters studies in the MIT/WHOI Joint Program were funded by the US Navy Civilian Institution Office.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.

Description: Phytoplankton are communities of diverse groups of prokaryotic and eukaryotic single-celled organisms responsible for nearly 50% of global primary production. The relative abundance of individual groups changes dynamically in response to environmental perturbations. Recent studies suggest that such changes are primarily driven by the distinct physiological responses employed by each group towards a particular perturbation. Although knowledge of some of these responses has come to light in recent years, many aspects of their metabolisms remain unknown. We attempt to address this gap by studying the metabolism of several phytoplankton groups using metabolomics. Firstly, we developed a method to enhance the analysis of untargeted metabolomics data. Secondly, we constructed two conceptual models describing how metabolism of the raphidophyte Heterosigma akashiwo responds to phosphorus and nitrogen stress. These conceptual models revealed several new stress response mechanisms not previously reported in other phytoplankton. Finally, we compared the metabolic changes of several distinct phytoplankton groups to uncover possible adaptation and acclimations that distinguish them. This analysis revealed several pathways and metabolites that represent the studied groups. The contributions of these pathways and metabolites towards physiology may support the ecological fitness of these organisms.

Description: None of this work would have been possible without a variety of funding sources. I was supported for three years by a National Science Foundation Graduate Research Fellowship and one year with a GEM fellowship. The research was carried out with grants from the MIT Microbiome Center (Award ID #6936800, EBK), the Simons Foundation (Award ID #509034, EBK), the Gordon and Betty Moore Foundation (Award ID #3304 EBK), the National Science Foundation (Award ID #OCE-0619608 to EBK and OCE-1057447 to EBK and MCKS) and the WHOI Ocean Ventures Fund.

Description: Große Erzählungen im Engelsjahr 2020 handeln von der Textilindustrie gestern und heute. Die vorliegenden kleinen Erzählungen spielen in anderen textilen Welten und jenseits der großen Fabriken. Von ihnen erzählt Friedrich Engels nicht. Dem Erzählten und Nicht-Erzählten auf der Spur finden wir schließlich heraus, dass auch zu Friedrich Engels selbst in einer bestimmten Weise erzählt - und nicht erzählt wird.

Description: Despite a strong connection between the Paris Agreement and the 2030 Agenda for Sustainable Development, climate change mitigation actions and sustainable development objectives are oftentimes not aligned efficiently, causing conflicts between the objectives. This thesis creates a systematic overview of conflicts of three renewable energy technologies with the Sustainable Development Goals (SDGs) by a literature review in Web of Science. The technologies solar energy, wind energy and hydropower function as examples for climate change mitigation actions. Out of 530 screened articles, 63 demonstrated conflicts. The systematic overview reveals that conflicts are different for each technology, but conflicts in regard to biodiversity loss and the degradation of natural habitats (SDG 15) and inequalities (SDG 10) were frequently identified for all technologies. The results of the systematic overview suggest that the site selection and the decision-making process on the construction of renewable energy projects are crucial stages to avoid conflicts with the SDGs.

Description: Die Emscher-Lippe Region ist seit vielen Jahren von einer intensiven wirtschaftlichen Transformation geprägt. Die fortschreitende De-Industrialisierung bzw. die Neuorientierung der Industrie nach dem Wegfall der Kohle- und Stahlindustrie stellt regionale Entscheidungsträger vor große Herausforderungen, wenn es darum geht, der hohen Arbeitslosenquote zu begegnen, Beschäftigungsquoten zu sichern, mit der prekären Finanzsituation in den kommunalen Haushalten umzugehen und den Wirtschaftsstandort zu stabilisieren und neu aufzustellen. Der Strukturwandel der Region ist mit Schließung der letzten Steinkohle-Zeche Ende 2018 nicht abgeschlossen, sondern geht mit dem Kohleausstieg im Energiesektor in eine zweite Phase. Dies sollte auch als Chance verstanden werden, den Wirtschaftsstandort Emscher-Lippe mit seinen energiereichen Industrien innovativ neu zu gestalten und die Region sowohl energetisch, als auch stofflich von der Nutzung fossiler Träger abzukoppeln. Eine wichtige Säule der regionalen Wirtschaftsförderung besteht darin, strategische Netzwerke und regionale Wertschöpfungsketten zu stärken, um die in der Region ansässigen (mittelständischen) Unternehmen zu unterstützen und den Strukturwandel innerhalb der dominierenden Industrien aus den Bereichen Energieerzeugung und chemischer Industrie zu begleiten. Die vorliegende Studie bereitet auf, welche Bedeutung die Wasserstoffwirtschaft in der Emscher-Lippe Region in diesem Zusammenhang derzeit spielt und zukünftig spielen könnte.

Description: Autowerke stellen ihre Produktion ein, die Börse stürzt ab, überall sieht man leere Straßen und Cafés und plötzlich ist Homeoffice für einen Großteil der arbeitenden Bevölkerung in Deutschland die Empfehlung oder gar eine Vorgabe. Die Corona-Pandemie bestimmt unseren derzeitigen Alltag und trifft Deutschland, Europa und die Welt zu einer Zeit, in der es ohnehin eine Vielzahl an gewaltigen Herausforderungen zu lösen gilt. Wirtschaftliche Hilfen sind während und im Nachgang einer solchen Krise unerlässlich, primär gilt aber die Konzentration auf die Verhinderung der ungebremsten Ausbreitung der Pandemie und auf die Begrenzung der gesundheitlichen Folgen. Zur Überwindung der langfristigen wirtschaftlichen Folgen derart disruptiver Entwicklungen sind Konjunkturprogramme und strukturelle Hilfen ein probates Mittel. Sie dürfen aber nicht nach dem "Gießkannenprinzip" verteilt werden, finanzielle Unterstützung muss zukunftsgerichtet für dringend notwendige Investitionen erfolgen. Ziel muss sein, damit erforderliche nachhaltige Transformationsprozesse innerhalb unserer Wirtschaft und Gesellschaft wie den Klimaschutz voranzutreiben. Die Vorbereitungen dazu müssten jetzt schon getroffen werden, sagen Manfred Fischedick und Uwe Schneidewind. Welche Kriterien und Maßnahmen es dafür braucht, zeigt ihr vorliegendes Diskussionspapier.

Description: Urbane Räume sehen sich verschiedenen ökologischen, sozialen und ökonomischen Herausforderungen gegenüber, für deren Bewältigung es unter anderem neue bzw. veränderte Handlungs- und Planungsansätze bedarf. Der Klimawandel mit seinen räumlich wirksamen Folgewirkungen ist eine der zentralen ökologischen Herausforderungen des 21. Jahrhunderts. Städte sind dabei sowohl Verursacher des Klimawandels als auch Betroffene. Sie sind Wohnort, Heimat, Arbeits- und Produktionsstätte. Durch ihre hohe Bevölkerungsdichte und durch die Agglomeration ökonomischen Kapitals sind Städte aber auch stark durch Extremereignisse wie Starkniederschläge und Hitzeperioden gefährdet. Grüne Infrastrukturen können daher nicht nur eine Strategie sein, um sich gegen die Klimawandelfolgen anzupassen, sondern bieten gleichzeitig das Potenzial für neue Lebensräume, um so das Artensterben zu mindern bzw. zu stoppen. Die vorliegende Konzeptstudie widmet sich der Frage, wie Straßen im Sinne des genannten Zieldreiecks weiterentwickelt und gestaltet werden können, d.h. wie eine Transformation urbaner Quartiersstraßen hin zu "lebenswerten" Stadt- und Straßenräumen erfolgen kann.

Description: Since urban processes need models of possible futures (referred to as travelling concepts) to drive their development, this study investigates whether planned-from-scratch smart city Kashiwa-no-ha International Campus Town Initiative can produce such an image with its smart governance approach, that is combined with an urban living lab. Using geographical governance research in relation to urban development processes as a framework, this master's thesis derives its own definition of the fuzzy concept of smart governance within the smart city vision based on a socio-geographical understanding of space, here referred to as Smart Urban Governance. Additionally, a set of indicators for the operationalisation of Smart Urban Governance is designed and applied to the case study. Methodologically, the thesis pursues a qualitative approach and, in this context, carries out a descriptive and normative governance analysis of Kashiwa-no-ha on the basis of the existing literature and empirical surveys conducted by the author. In summary, the strong role of academia in the urban planning context of community-building in Kashiwa-no-ha is exemplary and has led to a collaborative code of conduct between the traditional actors, mediated by a public-private-academic partnership, as well as to co-innovation between the city, developers, and citizens in form of a public-private-people partnership. Although the flagship project successfully addresses a large number of the Smart Urban Governance indicators defined in this context, there is potential for improvement, for example, in terms of participation, transparency, inclusion, and public spaces. Since Kashiwa-no-ha Smart City is still in an implementation phase until 2030, the thesis concludes with a forecast and a recommendation for action based on a strengths, weaknesses, opportunities, and threats analysis.

Description: Die gestiegene gesellschaftliche Relevanz von Reallaboren für die Gestaltung einer nachhaltigen Zukunft wird durch den vermehrten Einbezug von Reallaborkonzepten in verschiedenen politischen Strategien auf nationaler und internationaler Ebene deutlich. Weniger klar ist bisher, wie Reallabore für eine umweltorientierte Digitalpolitik genutzt werden können. Die vorliegende Kurzstudie "Reallabore als umweltbezogenes Politikinstrument" stellt konzeptionelle Grundlagen für Reallabore als Politikinstrument einer transformativen Umweltpolitik dar und leitet Handlungsempfehlungen für den zielgerichteten und wirkungsvollen Einsatz von Reallaboren im Rahmen einer umweltorientierten Digitalpolitik ab. In der Kurzstudie werden im Sinne der Digitalagenda des Bundesministeriums für Umwelt, Naturschutz und nukleare Sicherheit Reallabore als "Experimentierräume für digitalbasierte sozialökologische Innovationen, in denen digitale Tools, Anwendungen und neue Kooperationsstrukturen entwickelt und modellhaft getestet werden können" verstanden. Es wird erläutert, dass Reallabore auf bewährten Handlungsansätzen aufbauen und im Kontext einer nachhaltigen Digitalpolitik eine geeignete Ergänzung und Weiterentwicklung bisheriger Umweltpolitik darstellen können. Um Reallabore für digital- und umweltpolitischen Ziele besser zu nutzen, werden die drei folgenden Strategien empfohlen: I) Förderprogramm für Reallabore der nachhaltigen Digitalisierung, II) Wissenstransfer für nachhaltigen Wandel in der Digitalisierung und III) Forschung zur digitalen und partizipativen Entwicklung von rechtlichen und planerischen Politikinstrumenten.

Description: Im vergangenen Jahr waren die Zuwachszahlen im Bereich der Elektromobilität in Deutschland höher als jemals zuvor. Das enorme Wachstum ist vor allem der EU-Verordnung zur Flottenemissionsnorm zu verdanken. Die Elektromobilität hat damit einen wichtigen Schritt gemacht und gezeigt, dass sie das Potenzial hat, den Verbrennungsmotor bald zu verdrängen. Doch allein ein sehr hoher Marktanteil an Elektroautos genügt nicht, um die mittelfristigen deutschen Klimaschutzziele zu erreichen. Dies ist eine der zentralen Aussagen der Autoren des vorliegenden Impulspapiers. Sie empfehlen, dass die Europäische Union Herstellern weiterhin ambitionierte Zielvorgaben für emissionsarme Pkw machen sollte, damit schon im Jahr 2030 annähernd alle neu zugelassenen Pkw elektrisch angetrieben werden. Autos mit Hybridantrieb sind auf diesem Weg maximal eine wichtige Übergangstechnologie. Zentrale Voraussetzung ist zudem, dass die derzeitigen Ladevorgänge erleichtert werden, damit der Umstieg auf Fahrzeuge mit alternativem Antriebskonzept deutlich attraktiver wird.

Description: Welche Perspektiven haben zukunftsfähige und krisenfeste Städte nach der Corona-Pandemie? Antworten darauf skizzieren die Autorinnen und Autoren in dem vorliegenden Diskussionspapier. Ihre zentrale These: Städte der Zukunft müssen und werden "näher", "öffentlicher" und "agiler" sein. Dies erläutern sie anhand dieser drei Dimensionen und konkretisieren es anhand zahlreicher Beispiele.

Description: Gerechter Strukturwandel ist ein von den Gewerkschaften entwickeltes Konzept, das die Notwendigkeit einer ökologisch und sozial nachhaltigen Dekarbonisierung hervorhebt. Diese Masterarbeit wendet das Konzept auf den Braunkohleausstieg in Deutschland an. Der Erfolg des Übergangs hängt davon ab, ob er als gerecht empfunden wird. Den benachteiligten Gruppen im Strukturwandel muss eine Perspektive gegeben werden, um Akzeptanz für den Strukturwandel zu schaffen. Im Rahmen der Masterarbeit werden politische Maßnahmen für eine Governance des "Gerechten Strukturwandels" entwickelt. Die Arbeit basiert auf einer Fallstudie, die von Mai bis Juli 2019 im rheinischen Braunkohlerevier durchgeführt wurde. Methodisch wurde die Anwendung von semi-strukturierten Interviews gewählt. Insgesamt wurden sechs Expertinnen und Experten-Interviews mit Bürgerinitiativen, Gewerkschaften und Vertreterinnen und Vertreter des Landes Nordrhein-Westfalen ausgewertet. Die Ergebnisse belegen die Notwendigkeit politischer Maßnahmen in verschiedenen Bereichen, zum Beispiel: Während Beschäftigten der etablierten Unternehmen der Braunkohleindustrie der Übergang durch eine Reihe von Politikmaßnahmen erleichtert wird, müssen Beschäftigte in Subunternehmen den Strukturwandel weitestgehend alleine bewältigen. Letztere sind einem hohen Risiko ausgesetzt, aufgrund des Braunkohleausstiegs ihre Arbeitsplätze zu verlieren. Weiterhin zeigten die Befragungen, dass Boden im rheinischen Braunkohlerevier zu einer knappen Ressource werden könnte. Infolge des Braunkohleabbaus in der Region befindet sich ein großer Teil des Bodens im Eigentum des Energieversorgers RWE, der das Land durch bergrechtliche Enteignung erhalten hat. Wenn das Land nicht an die Kommunen zurückgegeben wird, wird eine unabhängige wirtschaftliche Neuausrichtung der Region nach dem Kohleabbau wesentlich erschwert. Aus dem Akteurzentrierten Institutionalismus werden Governance-Ansätze abgeleitet, die Lösungsansätze für diese Problemfelder bieten. Die Masterarbeit zeigt unter anderem, wie eine für die Partizipation notwendige Verteilung von Ressourcen einen Gerechten Strukturwandel befördern kann und warum ein integratives regionales Entwicklungskonzept des Landes NRW einer reinen wirtschaftlichen Förderung der Region vorgezogen werden sollte.