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Cumulative effects from multiple anthropogenic stressors over the past three centuries have severely impacted estuarine and coastal habitats, with cascading effects on the species that rely upon them. Pacific salmon (Oncorhynchus sp.) are migratory species that use estuaries as juveniles and as adults and deliver critical nutrients to coastal ecosystems as they move between fresh and marine waters. Many once abundant salmon populations have been extirpated or are in severe decline relative to historic levels, yet the strength of the relationship between habitat loss and population productivity has been challenged. In this dissertation, I applied field studies, otolith analyses, and conservation decision science tools to investigate the relative importance of estuarine habitat to salmon populations, with the aim of advancing effective management solutions for these species and their habitats. First, I conducted a two-year field survey of fish communities in the Fraser River estuary, British Columbia, Canada comparing the species richness and relative catch amongst three distinct habitats. I found that this impacted estuary still supported a rich community of migratory marine and anadromous fishes, as well as resident estuarine fish species. Each habitat supported some unique fish assemblages, with eelgrass supporting the highest catch and diversity of fishes overall but brackish marsh supporting the highest and most consistent catch of salmonids. Next, I used otolith analyses to quantify the residency and growth of juvenile Chinook salmon in the estuary. I found that for one of the only two remaining Chinook salmon stocks abundant enough to still support limited harvest in the Fraser River, the estuary provides vital rearing habitat, with juveniles residing in the estuary for an average of 6 weeks, during which time they had mean daily growth rates of 0.57 mm fork length, approximating growth in healthier estuarine systems. The use of these habitats by juvenile Chinook salmon had not been quantified previously, so these findings directly inform management of this population, which was recently designated as Threatened by the Committee on the Status of Endangered Wildlife in Canada. Finally, I applied Priority Threat Management, a conservation decision science framework, to predict the future status of Pacific salmon in the lower Fraser River and identify the most cost-effective conservation solutions out of a suite of alternative management strategies. On our current trajectory none of these populations were predicted to be assessed as ‘green’ or healthy status at the end of 25 years. In contrast, implementation of broad scale habitat restoration, protection, and watershed management could considerably improve the viability of the lower Fraser to support these salmon, such that many (14/19) of these populations would have a >50% likelihood of being assessed as healthy. Together, this research provides novel evidence of active and selective use of estuarine habitats by juvenile salmon, reliance on estuarine habitat for early marine growth by juvenile Chinook salmon, and a direct link between habitat health and population status for lower Fraser River salmon populations. / Graduate / 2023-04-13

Understanding and modeling microbial responses and feedbacks to climate change is hampered by a lack of a framework in the pelagic environment by which to link local mechanism to large scale patterns. Where terrestrial ecology draws from landscape theory and practice to address issues of scale, the pelagic seascape concept is still in its infancy. We have applied the patch mosaic paradigm of landscape ecology to the study of the seasonal and interannual variability of the North Pacific to facilitate comparative analysis between pelagic ecosystems and provide spatiotemporal context for eulerian time-series studies. Using multivariate, 13-year climatologies of sea surface temperature, photosynthetically active radiation, and chlorophyll a derived from remote sensing observations, we classified hierarchical seascapes at monthly and interannual scales. These dynamic, objectively-determined seascapes offer improved hydrographic coherence relative to oceanic regions with subjectively defined and static boundaries (Chapter 2) and represent unique biogeochemical functioning (Chapter 2) and microbial communities (Chapter3). Furthermore they provide consilience between satellite studies and in situ observations (Chapter 4) and allow for objective comparison of ecosystem forcing (Chapters, 4 and 5). In Chapter 2, we rigorously tested the assumption that satellite-derived seascapes describe regions of biogeochemical coherence. The seasonal cycle of the North Pacific was characterized at three levels of spatiotemporal hierarchy and broader relevance of monthly ���resolved seascapes was assessed through analysis of variance (ANOVA) and multiple linear regression (MLR) analyses of nutrient, primary productivity, and pCO��� data. Distinct nutrient and primary productivity regimes were well-characterized in the coarsest two levels of hierarchy (ANOVA, R�� = 0.5-0.7). Finer scale partitioning was more relevant for pCO���. MLR analyses revealed differential forcing on pCO��� across seascapes and hierarchical levels and a 33 % reduction in mean model error with increased partitioning (from 18.5 ��atm to 12.0 ��atm pCO���). In Chapter 3 we verified the seascapes with in situ collections of microbial abundance and structure. Flow cytometry data was collected from two long term time series and several cruises spanning thousand kilometers of the NE Pacific; these data allowed us to quantify spatiotemporal patterns. In addition, multiple response permutation analysis revealed differences in community structure across discrete seascapes, in terms of both absolute and relative abundances. Principal component analysis of the assemblage supported seascape divisions and revealed structure along environmental gradients with strong associations with chlorophyll a and sea surface temperature and, to a lesser extent, with mixed layer depth and mean photosynthetically active radiation in the mixed layer. Differences of assemblage structure between seascapes and strength of environmental forcing were strong in the subarctic and transition zones, but less pronounced in the subtropics, suggesting satellite-detected changes in bulk properties that may be associated with local physiology or interannual shifts in seascape boundaries. Based on the work presented in Chapter 4, we discovered that interannual shifts in the boundaries of a transition seascape and two distinct oligotrophic subtropical seascapes affect the variability observed at benchmark time series Station ALOHA; the latter two seascapes oscillate in their contributions to the expansion of the entire subtropics. On interannual scales, in situ phytoplankton abundance (as measured by chl-a), net primary productivity (NPP), and the relative abundance of eukaryotic phytoplankton and Synechococcus sp. increased during periods of encroachment by the transition seascape. Conversely, the relative abundance of Prochlorococcus increased and chl ���a and NPP decreased when the highly oligotrophic seascape encroached on Station ALOHA. The dynamic range (~6 million km��) of subtropical expansion is born almost entirely by the transition zone - resulting in a transfer of ~1.2 Pg of total primary C production between a system primed for export production and one dominated by the microbial loop. In Chapter 5, we investigated multiple factors that contribute to the effectiveness of the biological pump in the transition seascape. Near-continuous measurements of net primary production (NPP), net community production (NCP) and several ecophysiological variables were collected in across subarctic, transition, and subtropical seascapes of the Northeast Pacific during August and September of 2008. Mesoscale processes and shifts in community structure contributed to high export efficiency in the subtropical seascape; the convergence of assemblage structure, high biomass, moderate NPP: NCP and high NCP contributed to biologically mediated air-sea exchange in the transition seascape. Furthermore, NPP and NCP were strongly spatially coupled in both the transition (r[subscript 1, 39]=0.70; p<0.0001) and subtropical seascapes (r[subscript 1, 45]= 0.68, p<0.0001), suggesting the possibility for empirical modeling efforts. This dissertation provides a first step to characterize the seascape variability in the NE Pacific and to understand the modulation of primary and export production in a critical transition region. The multivariate seascape approach described here provides spatiotemporal context for in situ studies and allows objective comparisons of systems' responses to climatic forcing. An integrated ocean observing system will require insight from in situ observations and experiments, ecosystem models, and satellite remote sensing. The results highlighted in this dissertation suggest that the pelagic seascape framework, through its capacity to scale both context and mechanism, may serve as an important and unifying component of such an observing system. / Graduation date: 2013

The study is developed from five in-depth interviews with individuals from different walks of life who have interacted significantly with the North Sea. The study discusses change in the North Sea specifically in the development of fixed turbine wind farms and their physical and aesthetic effects. Observations speakers make as to changes in the North Sea and as to its beauty are contextualised and discussed using NASA satellite images, photographs and review of available academic literature, UK policy documents and law. This context includes a study of the industrialised North Sea with reference to the sediment sea plumes behind monopile turbines. The United Kingdom was selected for particular study of its wind farm development permissions process, including evaluations of seascape and the requirement of independence for expert evidence. Decline of trawler access to the North Sea is referenced to wind farm growth, and to adverse changes in public opinion leading to closure of the UK Dogger Bank to trawlers. Finality of wind farm development decisions is considered against the prospect of overturn by the courts. This aspect covers the application and development of principles relating to appeal by way of judicial review in the UK jurisdictions of Scotland, England and Wales, and Northern Ireland. The study identifies, and explains the English aesthetic evaluation of wind farms. It concludes that sea plumes are the result of a legal choice to allow permit applications to succeed without testing by reference to detailed in-sea turbine dimensions. In the permissions process (a) sea plumes are not evaluated by the seascape criteria applicable to coastal or off-coastal wind farms (b) deep offshore wind farms are instead evaluated by possible changes to character of the sea. The study further concludes that (i) the open horizon of the North Sea has been lost in significant part (ii) the combined aesthetic of transience, decay, and nostalgia underlies the aesthetic of the North Sea Maunsell forts (contrasted to Sealand), and also underlies attitudes to decommissioning wind farms, and (iii) concepts of sea beauty may be based on appearance or health, being regulated by different legal regimes in each eventuality (respectively the European Landscape Convention, or the OSPAR/ biodiversity/ habitat initiatives)

In der vorliegenden Arbeit wird die Bedeutung der Landschafts- und Marinemalerei für die nationale Einheit und bürgerliche Identifikation im Kaiserreich und in der Weimarer Republik beispielhaft am Werk des Berliner Secessionskünstlers Ulrich Hübner (1872-1932) untersucht. Zu Beginn wird die Rolle der Landschaft für die Konstitution von Staatswesen und nationaler Identität allgemein erläutert, um deutlich zu machen, vor welchem Hintergrund die Landschaftsmalerei Ulrich Hübners einen Beitrag zur bürgerlich-nationalen Identitätsfindung im (neugegründeten) Nationalstaat leisten konnte. Im Hauptteil werden dazu anhand Hübners biographischer Stationen unterschiedliche Gesichtspunkte, wie die pluralistischen Einflüsse auf Hübners Landschaftsmalerei, seine Rolle in der Berliner Secession, seine Positionierung auf dem Kunstmarkt, seine Rezeption durch die Kunstkritik und seine Funktion an der Akademie der Künste, untersucht. Hübners Konzentration auf Küstendarstellungen, Seestücke und Stadtansichten führte in Abgrenzung zur Marinemalerei zu dem neuen Typus der Stadt- und Wasserlandschaft, zwischen klassischer Veduten- und Landschaftsmalerei und impressionistischen Stimmungsbildern. Auf Grundlage des erstellten Werkverzeichnisses wird durch die Betrachtung Hübners Werks im Gesamtzusammenhang des Berliner Kunstgeschehens unter dem Aspekt des wirtschaftlichen und gesellschaftlichen Erfolges und der Entwicklung des privatwirtschaftlichen Kunstmarktes deutlich, wie ein Künstler in diesem System agierte. Hübners Erfolg mit dem neuen Typus der Stadtlandschaft und der Konzentration auf bestimmte Vertriebswege und erfolgreiche Motive steht exemplarisch für den deutschen Impressionismus in Zeiten des Stilpluralismus. Als Vertreter einer moderaten Moderne wurden seine Gemälde heimatlicher Landschaften Identifikationsbilder des aufgeschlossenen Bürgertums und somit eine Versicherung von Kontinuität in den politisch bewegten Zeiten vom Kaiserreich bis zum Ende der Weimarer Republik. / This doctoral thesis examines the significance of landscape and maritime painting for the national unity and civil identification in Imperial Germany and the Weimar Republic through the case study of the oeuvre of the Berlin Secession artist Ulrich Hübner (1872-1932). In the first instance, we will outline the effect that landscape painting in general had on the constitution of the political system and national identity in order to assess the extent of which Hübner’s landscape painting contributed towards the shaping of a civil-national identity in the newly founded nation state. To this effect we will then study key events in his biography, focusing on the following aspects: the pluralist influences that shape Hübner’s landscape painting, his role in the Berlin Secession, his place in the art market, art criticism’s response to his work and his position at the Berlin Academy of Arts. Hübner’s focus on coastal views, sea- and cityscapes, as opposed to maritime painting, lead to the new type of Urban Landscape and Waterscape which is situated between classical Veduta and landscape painting on one hand and impressionist “Stimmungsbilder” on the other. The catalogue raisonné will form the basis on which we examine his oeuvre in the context of the greater Berlin art scene with particular emphasis on his commercial and social success on one hand as well as seen within the more specific framework which is the development of the commercial art market on the other. The success Hübner had with his new type of Urban Landscape and his focus on specific commercial channels and successful subject matters is exemplary for the German Impressionism in times of stylistic pluralism. Representing a moderate Modernism, his paintings of “Heimat”-landscapes became symbols that the liberal bourgeoisie could identify with and thereby a guarantee of continuity during the politically agitated times from the beginning of the German Empire to the end of the Weimar Republic.