Thèses sur le sujet « Atlantic Ocean Region »

The role of heterotrophic bacteria in the carbon and nitrogen flux of the pelagic food web was investigated during laboratory and field-based studies of the temporal development of the planktonic community after upwelling. Bacterial community structure, activity and production were closely coupled to the upwelling cycle and to the dynamics of the phytoplankton community. The initial bacterial population (<l x 10⁶ cells ml⁻¹, 20 to 40 μg C l⁻¹) was metabolically dormant. Increased availability of phytosynthetically produced dissolved organic carbon (PDOC) stimulated bacterial growth (0.016 h⁻¹) and abundance (8 to 10 x 10⁶ cells ml⁻¹, 140 to 200 μg C l⁻¹). Rapid successions in the dominant plateable strains were attributed to substrate preferences and substrate availability. Significant correlations of bacterial biomass with total standing stocks of phytoplankton and particulate carbon provided evidence of close coupling between bacteria and PDOC, and between bacteria and recalcitrant substrates available during phytoplankton decay. These relationships were best described by power functions, suggesting that bacterial biomass was relatively reduced at high levels by predation. A microcosm study indicated that zooflagellate predation could control bacterial biomass. Low net growth yields (34 to 36%) of flagellates suggested inefficient transfer of carbon to higher trophic levels, but considerable nitrogen regeneration (ca 6 to 7 μg N mg dry weight⁻¹ h⁻¹). Thymidine-measured bacterial production (TTI, <0.1 to 1.25 mg C m⁻³ h⁻¹) was linearly related to phytoplankton growth. Non-uniform response of bacteria to added tracer substrates may result in underestimates of bacterial production by 2 to 34 times by TTI, particularly in deep or oligotrophic waters, or during phytoplankton decay. Close coupling of copepod (Calanoides carinatus) production to the upwelling cycle suggested co-existence of the microbial food web and the classical diatom-copepod food chain. Recently upwelled water was dominated by phytoplankton. Assuming that all phytoplankton carbon was available for utilisation, copepods and bacteria were calculated to consume approximately 12 and 22% of primary production respectively. As the bloom declined the planktonic community was increasingly dominated by bacteria, detritus and mesozooplankton. On average, copepods consumed 60% of primary production, while bacteria consumed 49%. Carbon consumption requirements of both bacteria and copepods were satisfied by resource partitioning and carbon cycling. Under food-limiting conditions herbivorous copepods may switch to omnivory, ingesting microzooplankton of the microbial food web, and stimulating enhanced remineralisation to further sustain primary production. A generic size-based simulation model of the dynamics of the plankton community indicated that bacteria and the microbial food web increase the overall productivity of the planktonic food web, and that heterotroph predation in the smaller size classes (<200 μm) is an important mechanism in nutrient recycling.

The El Niño-Southern Oscillation (ENSO) is a natural mode of climate variability in the tropical Pacific, which not only perturbs the local atmosphere, but whose impacts can also reach remote, extra-tropical regions through atmospheric teleconnections. While the atmospheric response to ENSO and the dynamics of its teleconnections are well assessed in certain locations, such as the North Pacific-American sector, it is not the case for the North Atlantic-European (NAE) sector. In this thesis, the dynamics of the ENSO-NAE teleconnection are assessed in late winter (January-March), the season in which a significant and robust ENSO-related signal has been reported in the literature. Part of this well-known late-winter ENSO signal is a sea-level pressure (SLP) dipole in the North Atlantic. In this thesis, it is assessed that this “canonical” dipole is mostly driven by tropospheric dynamics and is related to the large-scale Rossby wave train triggered from the tropical Pacific by the anomalous upper-level divergence associated with ENSO. The “canonical” SLP dipole is known to be reminiscent of the surface signature of the North Atlantic Oscillation (NAO), which is the dominant mode of variability in the North Atlantic. The relationship between the ENSO-forced response in the NAE region and the NAO is examined: it is found that no further similarities are evident apart from the surface SLP signature, and it is suggested that ENSO and the NAO are largely unrelated. Another issue tackled in this thesis is the (a)symmetry of the atmospheric signal associated with the two phases of ENSO, El Niño and La Niña, which show roughly opposite patterns of sea surface temperature (SST) anomalies in the tropical Pacific but not necessarily a symmetric atmospheric response. It is noticed that, in a set of sensitivity experiments with three state-of-the-art models, the extra-tropical response in the troposphere is slightly asymmetric in amplitude and longitudinal location. However, it is highlighted that the mechanisms at play, in particular concerning the response in the NAE region, are the same for El Niño and La Niña. The ENSO impact on the Northern Hemisphere polar stratosphere is also studied, since a stratospheric pathway of the ENSO-NAE teleconnection has been suggested in the literature, and an ENSO signal in the polar stratosphere has been previously reported. In the same set of experiments, it is assessed that the stratospheric response to La Niña is symmetric in structure to that of El Niño, but with smaller amplitude. This response is found in both the lower and middle-upper stratosphere and is suggested to be related to the upward propagation of the ENSO-forced tropospheric Rossby wave train, and specifically to its center of action located over North America/Canada. In the middle-upper stratosphere, the anomalies project onto a wavenumber-1 pattern and show a westward tilt with height that indicates upward wave propagation rather than wave-breaking, as previously suggested. Finally, it is noticed that the well-established “canonical” dipole is mostly located over the North Atlantic, while less is known about the ENSO signal over the European continent. A novel ray-tracing approach that considers zonal asymmetries in the background flow is developed to examine potential tropospheric pathways of the ENSO teleconnection to Europe. In some cases, a SLP pattern featuring a single anomaly over Europe is present, which appears to be linked to the ENSO wave train emanated from the tropical Pacific via a split over northern North America or via reflection due to zonal inhomogeneities in the background flow. Alternatively, a wave-like pattern with two opposite-signed SLP anomalies over Europe is observed, which is suggested to be related to a secondary wave train emerging from the tropical Atlantic.
El Niño-Oscilación del Sur (por sus siglas en inglés, ENSO) es un modo de variabilidad climática natural del Pacífico Tropical, el cual, a través de teleconexiones atmosféricas, puede tener impactos a nivel global. El objetivo de esta tesis es explorar la dinámica de la teleconexión entre ENSO y la zona del Atlántico Norte y Europa a finales del invierno (de enero a marzo). Los resultados indican que la señal principal de ENSO en el Atlántico Norte, una anomalía dipolar de presión atmosférica a nivel del mar (SLP, en inglés), está principalmente asociada al tren de ondas de Rossby troposférico generado por ENSO. También se analiza la relación entre la respuesta forzada por ENSO y la Oscilación del Atlántico Norte (por sus siglas en inglés, NAO), principal modo de variabilidad interna regional; los resultados muestran que ENSO y la NAO parecen no estar relacionados dinámicamente. Otro aspecto tratado en esta tesis es la asimetría de la respuesta atmosférica relacionada con las dos fases de ENSO, El Niño y La Niña. En una serie de experimentos con modelos climáticos, se observa que la señal en la troposfera es ligeramente asimétrica en términos de amplitud y localización en longitud. No obstante, se ha encontrado que los mecanismos de la respuesta atmosférica son los mismos para El Niño y La Niña. También se estudia la asimetría de las anomalías en la estratosfera polar, y se observa que la respuesta a La Niña tiene una estructura simétrica a la de El Niño, pero con menor amplitud. Además, esta estructura parece estar relacionada con la propagación vertical del tren de ondas de Rossby troposférico. Finalmente, utilizando un algoritmo innovador de trazado de rayos, se investigan las potenciales rutas de la teleconexión troposférica entre ENSO y el continente europeo. Se encuentran dos patrones típicos de SLP. El primero parece estar relacionado con el tren de ondas del Pacifico Tropical bien a través de una bifurcación a la altura del norte de Norte América, o bien a través de una reflexión debida a inhomogeneidades en el flujo medio. El otro patrón, en cambio, parece estar asociado a un tren de ondas secundario procedente del Atlántico Tropical.

Thesis (Ph.D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 1999.
Includes bibliographical references (p. 180-184).
During July and August of 1996, a large acoustics/physical oceanography experiment was fielded in the Mid-Atlantic Bight, south of Nantucket Island, MA. Known as the Shelfbreak Front PRIMER Experiment, the study combined acoustic data from a moored array of sources and receivers with very high resolution physical oceanographic measurements. This thesis addresses two of the primary goals of the experiment, explaining the properties of acoustic propagation in the region, and tomographic inversion of the acoustic data. In addition, this thesis develops a new method for predicting acoustic coherence in such regions. Receptions from two 400 Hz tomography sources, transmitting from the continental slope onto the shelf, are analyzed. This data, along with forward propagation modeling utilizing SeaSoar thermohaline measurements, reveal that both the shelfbreak front and tidally-generated soliton packets produce stronger coupling between the acoustic waveguide modes than expected. Arrival time wander and signal spread show variability attributable to the presence of a shelf water meander, changes in frontal configuration, and variability in the soliton field. The highly-coupled nature of the acoustic mode propagation prevents detailed tomographic inversion. Instead, methods based on only the wander of the mode arrivals are used to estimate path-averaged temperatures and internal tide "strength". The modal phase structure function is introduced as a useful proxy for acoustic coherence, and is related via an integral transform to the environmental sound speed correlation function. Advantages of the method are its flexibility and division of the problem into independent contributions, such as from the water column and seabed.
by Brian J. Sperry.
Ph.D.

The present work focused on the possible influence of the Pacific Decadal Oscillation (PDO) on the positioning and intensity of the Intertropical Convergence Zone (ITCZ) during its annual cycle over the Atlantic Ocean and its impact in the rainfall totals in the northern South American continent. For this purpose, the mean annual fields of outgoing longwave radiation (OLR), sea surface temperature (SST), omega (ω), meridional wind (V) and precipitation rate (P) of Reanalysis data sets (NCEP/NCAR) were analysed. In addition, observed rainfall monthly mean series (INMET and HIDROWEB), the University of Delawere (UDEL) rainfall, interpolated in a 0.5°x0.5° grid, and the PDO indices found in the NOAA/ESRL/PSD site were used to support the analyses. The results were visualized with applets available in the ESRL/PSD/NOAA s site as well as GrADS software. The records period 1948-2005 was divided into PDO cold phase (1948-1976), warm phase (1977- 1998) and current phase (1999-2005), which was used to verify the climate tendency of the last seven years. The results suggested that the ITCZ remained farther north of its mean position during the PDO cold phase. Apparently, the ascending branch of the Hadley Cell was displaced farther north and the descendent branch of the Walker Circulation positioned farther west of their normal positions. This pattern led to a rainfall reduction in parts of Amazonia. In the PDO cold phase, the normalized rainfall indices showed a more noticeable rainfall reduction (increase) western (eastern) of 52°W, in the State of Pará. In the PDO warm phase, opposite circulation patterns and higher climate variability were observed. The results suggested that the PDO, in general, modified the SST patterns in the Atlantic and, as a consequence, the positioning and intensity of the ITCZ. There are evidences that the PDO is experiencing a new cold phase. Thus, one expects that the ITCZ and the Amazonian rainfall present a similar behaviour of previous cold phase. Particular attention should be paid to the Brazilian States of Roraima and Maranhão, eastern Pará State and western Amazonas State, including Colombia, Venezuela e north-eastern Bolivia, that may experience a sensible rainfall reduction during the next 10 years. Another relevant result was relative to a possible enhancement of convection and rainfall over the southern Saharan region (Sahel), Africa, during the present PDO phase. It was noticed that it rained more in the region till 1975, when the SST anomalies of Equatorial Guinea Gulf were negative and the wind south component was stronger. These conditions seem to be returning.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
No presente trabalho dissertou-se sobre as possíveis influências da Oscilação Decadal do Pacífico (ODP) no posicionamento e intensidade da Zona de Convergência Intertropical (ZCIT) em seu ciclo anual sobre o Oceano Atlântico e seus impactos na precipitação do norte da América do Sul. Para tanto, foram utilizados os campos médios de radiação de ondas longas emergentes (ROLE), temperatura da superfície do mar (TSM), omega, vento meridional e precipitação, elaborados a partir do conjunto de dados de Reanalises do NCEP/NCAR, além de índices de ODP do ESRL/PSD/NOAA e séries temporais da precipitação média observada de postos pluviométricos (INMET and HIDROWEB) e a interpolada pela University of Delawere (UDEL) numa grade de 0,5°x0,5°. Os aplicativos disponíveis no site do ESRL/PSD/NOAA, bem como o GrADS, foram utilizados para visualizar os resultados das análises. O período de 1948 a 2005, correspondendo às fases fria (1948- 1976), quente (1977- 1998) e atual (1999- 2005) da ODP, foi tomado como base, este último tendo sido utilizado para verificar tendências climáticas contemporâneas. Os resultados indicaram que, durante a fase fria da ODP, a ZCIT esteve mais ao norte de sua posição climatológica. O ramo ascendente da célula de Hadley permaneceu mais deslocado para norte e o descendente da circulação de Walker mais deslocado para oeste. Essa configuração foi responsável pelo decréscimo da precipitação observado em parte da Amazônia. Os índices de precipitação padronizada (IPP) mostraram redução (aumento) mais acentuada da chuva a oeste (leste) de 52°W, no Estado do Pará. Durante a fase quente da ODP, foram observadas configurações opostas e maior variabilidade climática interanual. De maneira geral, as análises mostraram que a ODP mudou a configuração das TSM no Atlântico e influenciou o posicionamento e intensidade da ZCIT. Sugeriram, também, que a ODP parece estar experimentando sua nova fase fria. Com base nesses resultados, espera-se que a ZCIT e a precipitação, apresentem variabilidade semelhante à fase fria anterior. Dessa forma, particular atenção, deve ser atribuída a regiões dos Estados de Roraima, Oeste do Amazonas, leste do Pará e Maranhão, além da Colômbia, Venezuela e nordeste da Bolívia, que deverão sofrer redução em sua precipitação média nos próximos 10 a 15 anos. Outro resultado relevante diz respeito aumento da convecção e precipitação que poderá ocorrer no Sul do Deserto de Sahara (Sahel), África, ao longo da atual fase da ODP. Nessa região, foi notado que choveu mais até 1975, quando o Golfo da Guiné apresentou anomalias negativas de TSM e a componente sul do vento esteve mais forte.Aparentemente, essas condições estão retornando.

Les fluctuations du vent sont un des mecanismes pouvant generer la variabilite oceanique d'echelle moyenne, observee notamment dans l'atlantiuqe nord-est. La reponse de l'ocean est calculee par un modele numerique spectral, qui resout les equations quasi-geostrophiques dans le cas non lineaire et stratifie. Dans une premiere partie, nous decrivons la turbulence d'echelle moyenne generee par les fluctuations du vent dans un ocean a fond plat. L'energie de la reponse se partage entre un regime lineaire constitue d'ondes de rossby barotropes a grande echelle, et un regime non lineaire. Nous etudions la sensibilite de la reponse a tous les parametres physiques (echelle et energie du vent, frottement, rotation de la terre,stratification). Nos resulats montrent que le parametre cle est le rapport de la plus grande echelle forcee au rayon de rossby. Dans une seconde partie, nous etudions lm'influence d'une topographie aleatoire de faible hauteur sur la dynamique des tourbillons forces par le vent. La generation de courants moyens correles a la topographie est mise en evidence, ainsi qu'une diminution importante des echelles spatiales au fond. Enfin, nous montrons que la presence de topographie induit une intensification au fond dans le cas de la turbulence libre, et par contre une plus grande intensification en surface dans le cas de la turbulence forcee. La reponse de notre modele, surtout en presence de topographie, presente des caracteristiques proches de la variabilite observee dans l'atlantique nord-est, ce qui confirme l'importance des fluctuations du vent pour la generation de cette variabilite

The provinces of Río Negro and Neuquén are located in the northern Argentinean Patagonia. One of them, Neuquén, is at the foothills of the Andes; meanwhile, the other extends from this mountain chain to the Atlantic Ocean. In spite of their vicinity, their material and spiritual patrimonies are different enough to give each their own identity. At Neuquén, the richest petroleum deposits of Argentina are found, which provide most of the oil and gasto the country, giving a good share to Neuquén of the revenues from taxes collected. Furthermore, Neuquén also has other means for its economy based on landscape resources that have attracted the development of many tourist resorts. Lastly, it has fruit agriculture and flsheries with a heavy share of investment from  the prívate sector.In relation  to their spiritual patrimony,  even  if the two provinces  have contactpoints due to their territorial organization, they have also differences since both territories acquired the rank of provinces. In Neuquén, political and cultural factors determine local incentives toward development that leads to the formation of a regio­ nal society different from that of Río Negro. A local political party not enrolled in national parties plays a decisive role in development after the 1960s, and in the deflnition of the regional identity. At Río Negro, the migratory groups, especially Europeans, have heavily influenced in the formation of the local incentives to development. This paper explores ideas around these topics and tries to make a comparative analysis with respect to the formation of the local incentives and their development.
Las provincias de Río Negro y Neuquén están ubicadas en la porción septentrional de la Patagonia argentina. Una de ellas -Neuquén- se recuesta sobre la cordillera de los Andes, mientras que la otra -Río Negro- se extiende desde este cordón monta­ ñoso hasta el Atlántico.A pesar de su vecindad, sus patrimonios materiales y espirituales presentan parti­cularidades que otorgan a cada una de las provincias una identidad propia. En el caso neuquino, su territorio se caracteriza por albergar los yacimientos de hidrocarburos más ricos del país, haciendo  de esta provincia la primera productora de petróleo y gas. Esto le significa al Gobierno de Neuquén un importante ingreso por las regalías-aproximadamente  el 80% de su presupuesto-,  y para  la sociedad  en general,  unaeconomía fuertemente dependiente de los recursos provenientes de los hidrocarbu­ ros, así como dependiente del Estado. Río Negro, por su parte, se caracteriza por una economía más diversificada: recursos paisajísticos que han promovido un importante desarrollo turístico, fruticultura y pesca, con una mayor participación del sector pri­ vado. En cuanto al patrimonio espiritual, si bien tienen puntos de contacto en lo que respecta al proceso de organización territorial, también presentan especificidades a partir del momento en que ambos territorios toman el carácter de provincias. Con respecto a Neuquén, factores políticos y culturales determinan incentivos locales para el desarrollo que conducen a la formación de una sociedad regional diferente de su vecina rionegrina. Un partido político local no enrolado en ninguna de las corrientes nacionales mayoritarias jugará un rol decisivo a partir de los años sesenta en el desa­ rrollo y definición de la identidad regional. En el caso rionegrino, los grupos migratorios -mayoritariamente europeos- han incidido fuertemente en el proceso de formación de los incentivos locales para el desarrollo.La ponencia explora estos grandes tópicos con el fin de efectuar un análisis com­parativo con respecto al proceso de formación de los incentivos locales para el desa­rrollo y de sus resultados.

Thesis (M.S.)--Florida State University, 2006.
Advisor: Mark A. Bourassa, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed June 15, 2006). Document formatted into pages; contains vii, 30 pages. Includes bibliographical references.

During the Saharan Mineral Dust Experiment (SAMUM) 2008 field campaign, particles with geometric diameters between approximately 0.1 to 25 µm were collected on board of the Falcon sampling aircraft of the Deutsches Zentrum für Luft- und Raumfahrt (DLR, German Aerospace Centre). To investigate the spatial and vertical distribution of aerosol in the Cape Verde region, sampling was performed along the West African coastline and in the Cape Verde region. The chemical composition of these samples was determined by means of electron microscope single particle analysis. The major task of the conducted flights was to observe mixing of Saharan desert dust and biomass burning aerosol from the south Sahel belt. On all days investigated a distinct layer structure of biomass burning aerosol and desert dust layers was observed. The aerosol composition of the small particles (geometric diameter < 0.5 µm) was highly variable and in case of biomass burning strongly dominated by soot with up to 90 % relative number abundance. Internal mixtures of soot particles with mineral dust were not detected. Soot was only observed to mix with secondary sulphate. Biomass burning aerosol particles were enriched in potassium and chlorine originating from the vegetation matrix, and sulphur. After long travel times (aging), particles appeared to be depleted in chlorine and enriched in sulphur. The coarse particles (d > 0.5 µm) were dominated by silicates, which appeared to be mixtures of different minerals. In the Cape Verde region mineral dust is well mixed. For the aerosol arriving from central West Africa a determination of source regions by elemental or mineralogical composition was generally not possible. However, when the air mass followed another transport path, with longer travel time as observed for some high altitude trajectories, the dust origin appeared to be more in the south east of central West Africa, probably in the Bodélé. Refractive indices were calculated for each flight level, revealing a large variance in light absorption, resulting from the high number abundance of soot particles in the biomass burning layers. For a detailed modeling of radiation forcing and resulting effects on climate, the observed layer structure displaying different chemical and physical properties at the respective levels should be taken into account and might lead to some modification of the heretofore known results.

Defence date: 22 February 2017
Examining Board: Professor Jorge Flores, European University Institute; Professor Regina Grafe European University Institute; Professor Cátia Antunes European University Institute; Professor Gert Oostindie, KITLV/Royal Netherlands Institute of Southeast Asian and Caribbean Studies
When, in 1796, the British invasion fleet approached the Demerara River, its commanders were in for an unpleasant surprise. The expedition, arriving from Barbados with some 1,300 men, aimed to take possession of the Dutch colonies of Essequibo and Demerara on the Guiana coast of South America. Theoretically the British came to offer “protection” to the colonies in the name of the Dutch Stadtholder, in practice they were also keen on taking these lucrative colonies for themselves. The Dutch colonies of Essequibo and especially Demerara already had a high percentage of British planters, and their fertile soils carried the promise of great riches. The coffee, sugar and cotton planters could fuel the unfolding Industrial Revolution in Britain with the raw material for its machines and the consumer goods for its workforce.
Thesis chapter 4 'The commercial web : mercantilism, cash crops and captives as contraband' was previously published as and article in Tijdschrift voor Zeegeschiedenis (2013) and as a chapter in the book 'Beyond empires : global, self-organizing, cross-imperial networks, 1500-1800' (2016)

Marine litter is present throughout the world's oceans, representing a significant threat to marine ecosystems. While most efforts have focused on assessing ecological impacts, information on the socio-economic dimension of marine litter is scarce. Here we provide a detailed assessment of the direct economic costs of marine litter for a remote region of the North-East Atlantic, the Azores archipelago. Face-to-face interviews were performed to quantify and characterise the costs of marine litter-related incidents and coastal clean-ups to259 sea-users (fishermen, tourist operators and transport companies) and the costs of coastal clean-ups to 21 local authorities (parish councils, municipalities and harbours). We provide a detail characterisation of the frequency, type and costs of marine litter-related incidents and clean-ups along with an evaluation of the perceptions and opinions of different stakeholders on this issue. The average cost of a marine litter-related incident was €1618 (±401, SE), while the average cost associated with cleaning a coastal site was €10233 (±3597, SE) per local authority and year. Overall, marine litter pollution was estimated to cost a total of €710,698 (±195,181; SD) per year, which is the equivalent to 0.02% of the Gross Domestic Product of the Azores archipelago. Our results demonstrate that marine litter can significantly impact the activity of sea-users and represent an important economic burden for local authorities, thus, marine litter creates costs and inconveniences for a range of stakeholders engaged in marine activities and also increases the waste clean-up budgets of small communities living on remote islands. Quantifying the socio-economic implication of marine litter is crucial to further raise public awareness on this issue and demonstrate that the impacts are wide-ranging.
O lixo marinho é qualquer material duradouro, fabricado ou processado que é descartado, eliminado ou abandonado na costa ou no mar. Dos diferentes tipos de lixo marinho, os plásticos são sem dúvida, os mais abundantes e que causam mais impactos. É por isto que atualmente a poluição do meio marinho por este material é reconhecida como um problema que afeta ecossistemas e espécies globalmente, apesar de que a produção de plásticos em grande escala só começou na década dos anos 50. Cada ano, as deficiências no sistema de tratamento de resíduos e na reciclagem provocam grandes descargas de plásticos no meio marinho, tanto acidentais como intencionais. Uma vez no oceano, estes plásticos concentram-se à volta das grandes cidades e nos cinco Giros Subtropicais de correntes oceânicas, acabando por afetar regiões remotas localizadas longe das zonas principais de poluição. A poluição por plásticos é uma questão social séria para a qual os impactos estão apenas a começar a ser avaliados. Apesar de que nas últimas duas décadas houve um aumento dos estudos focados na quantificação dos impactos ecológicos desta problemática no ambiente marinho, ainda existe muito desconhecimento em várias áreas. Assim por exemplo, até agora dedicou-se pouca atenção às implicações económicas que o lixo marinho causa em diferentes sectores. Neste sentido, poucos investigadores têem aprofundado este tema apesar de evidências que demostram que uma ampla gama de setores económicos pode estar potencialmente afetados pelo lixo marinho, o qual atua como um fardo económico significativo para as comunidades costeiras e ataca diretamente as indústrias de turismo, pesca e transporte marítimo. Por exemplo, um estudo que usou dados das estatísticas de seguros do Sistema Nacional das Pescas no Japão mostrou que os custos associados a incidentes relacionados com lixo marinho, incluindo colisões, emaranhamentos das hélices em lixo e entupimentos nas bombas de água, correspondia a um custo para a indústria pesqueira de US $18,450 milhões anuais em 1985. Da mesma forma, em 21 economias da região da Ásia-Pacífico, os custos de danos causados por lixo marinho nas hélices de barcos e sistemas de refrigeração de pequenos navios foram estimados em US $1.26 bilhões por ano. Mas, além destes problemas causados aos utilizadores do mar, a limpeza da orla costeira pode representar outros custos significativos para comunidades costeiras. Um estudo realizado na UE em 1998 mostrou que as limpezas de praias representavam um total de 2.9 milhões de libras por ano, incluindo a recolha e o transporte de lixo marinho, taxas de descarte, força de trabalho e equipamentos. Na Holanda, o município turístico de Den Haag estimou gastar aproximadamente 0.5 milhões de euros por ano para remover lixo marinho das áreas costeiras. Portanto, os gastos relacionados com o lixo marinho podem ser significativos, mesmo quando consideramos pequenas comunidades. O arquipélago dos Açores, um grupo remoto de ilhas vulcânicas localizadas no extremo Nordeste do Oceano Atlântico, é particularmente afetado pelo lixo marinho. Mais especificamente, um estudo realizado nesta região reportou que 83% das tartarugas marinhas analisadas tinham ingerido itens de plástico. Além disso, outros estudos nos Açores demostraram que grandes quantidades de itens da pesca, especialmente equipamentos de pesca perdidos ou descartados intencionalmente, estão presentes no fundo do mar perto de áreas costeiras, nas montanhas submarinas, mas também a flutuar na superfície da água. O objetivo deste trabalho de tese foi quantificar o impacto económico direto e os custos associados ao lixo marinho para a economia do arquipélago dos Açores. Os Açores têm um grande território marinho, onde atividades como a pesca e o turismo são alguns dos setores mais importantes para a economia do arquipélago. Através do uso de entrevistas pessoais, este estudo fornece uma caracterização detalhada da frequência e do tipo de incidentes causados pelo lixo marinho aos principais usuários do mar. Com o objetivo de ter uma avaliação económica abrangente para esta questão, também foram entrevistadas autoridades locais que permitissem estimar o custo das limpezas costeiras. Por fim, foram exploradas as perceções e opiniões das partes interessadas em relação a esta problemática. Esta avaliação socioeconómica contribui para um maior esforço de investigação nesta área com o objetivo de estabelecer uma base que quantifique e caracterize toda a gama de impactos causados pela poluição por plásticos na região dos Açores. Neste estudo foram entrevistados 259 utilizadores do mar (pescadores profissionais e recreativos, empresas marítimas turísticas e empresas de transportes de mercadorias) e 21 autoridades locais gestoras de zonas costeiras (Câmaras Municipais, Juntas de Freguesia, Portos e Marinas). Dos 327 barcos avaliados, um total de 95 barcos reportou incidentes, o que dá uma frequência percentual de ocorrência (%FO) de incidentes relacionados a lixo marinho de 29%. O emaranhado de lixo marinho foi o incidente mais comumente relatado (92%), geralmente associado à hélice do barco (68%; n = 76), mas também as artes de pesca ativas (24%; n = 27) de ambos, tanto pescadores profissionais como pescadores recreativos. Outros tipos de incidentes incluem aqueles onde itens de lixo entopem a bomba de água (4%; n = 5), um problema que afetou a todos os usuários do mar a exceção dos pescadores recreativos. Também foram reportadas colisões com lixo marinho (4%; n = 4), mas apenas por pescadores profissionais e operadores marítimo turísticos. Os resultados obtidos demostram que o custo médio que os utilizadores do mar devem suportar após um incidente relacionado com o lixo marinho é de €1617 (±400, SE), enquanto que o custo médio associado à limpeza de um local costeiro é de €10,233 (± 3597, SE) por ano. Finalmente, a extrapolação destes resultados a todo o Arquipélago dos Açores demostra que o lixo marinho tem um impacto económico estimado de €710,698 (±195,181, SD) por ano. Este valor corresponde a 0.02% do Produto Interno Bruto (PIB) total para os Açores no mesmo ano (PIB: €3,962,000,000, SREA). Em todo o mundo ainda existe um entendimento limitado das implicações económicas do lixo marinho para as comunidades costeiras, principalmente para as regiões remotas. O fato de este estudo mostrar como este problema também está presente num arquipélago oceânico, pode-se incentivar outros investigadores a realizar avaliações económicas semelhantes sobre os impactos económicos do lixo marinho em novos locais. Sendo que nossa sociedade é predominantemente impulsionada por interesses económicos, essas avaliações económicas podem aumentar a conscientização e ajudar a direcionar esforços futuros para controlar a entrada de lixo no meio marinho, e paralelamente, disparar o alarme sobre as consequências de nosso consumo crescente de plásticos.

The impacts of climate change are already being experienced by the most vulnerable countries around the world, particularly small island developing states (SIDS). Many SIDS are isolated, and environmentally and economically exposed. Together, these 58 countries constitute a uniquely vulnerable grouping of developing countries whose national governments are prioritising climate change adaptation in order to ensure their sustainable development. In spite of the importance and urgency of adaptation for SIDS, there is little evidence in the academic literature about how these countries, as a whole and spread across the Atlantic, Indian Ocean, Mediterranean and South China Sea, Caribbean and Pacific regions, are adapting to climate change. This thesis helps to fill this gap. Prepared as a compilation of academic papers accepted for publication in leading peer-reviewed journals, this thesis takes a meta-paradigmatic, research-led, mixed methods, comparative case study approach to answering two primary questions—How are SIDS adapting to climate change at the national level? and What are the factors that affect adaptation at the national level in SIDS? There are eight sub-questions associated with the second primary question. These were derived from the answers to the first primary question. They explore the trends in and determinants of international adaptation financing to SIDS; the effectiveness of regional organisations coordinating adaptation responses across SIDS; the drivers of and barriers to mainstreaming adaptation into national development policies and programs in SIDS; and the nature and potential range of adaptation limits in SIDS. Key findings of this research include that: (1) SIDS are primarily engaged in the observation and assessment of climate variables and in education and knowledge management activities but less so in actual implementation, and monitoring and evaluation; (2) the allocation and sources of adaptation financing to SIDS are highly skewed and that governance quality is a strong determinant of adaptation financing to SIDS; (3) regional organisations are least effective in relation to their implementation and management of regional adaptation projects and programs across SIDS; (4) institutions and organisations, ‘champions’, personalities and informal networks, and risk and exposure are the main drivers of adaptation mainstreaming in SIDS; competing development priorities, poor planning and governance, and insufficient manpower and human resources are the main barriers; and (5) institutional constraints, as opposed to physical and ecological constraints, are potentially stronger drivers of adaptation limits in SIDS. This thesis makes a number of important contributions to the academic literature. These include: (1) offering one of the first cross-regional analyses of adaptation in SIDS; (2) documenting the experience of SIDS with accessing adaptation financing; (3) developing a framework for assessing the effectiveness of regional organisations coordinating adaptation in SIDS, which organisations can apply themselves; and (4) developing a seven-step process for practically achieving adaptation mainstreaming in SIDS. This body of work is especially useful for national governments, regional and international organisations as well as other actors involved in national-level climate change adaptation in SIDS—it highlights gaps in adaptation action requiring their attention.