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Mineral dust plays an important role in the ocean’s carbon cycle through the input of nutrientsand metals which potentially fertilise phytoplankton, and by ballasting organic matter from the surface ocean to the sea floor. However, time series and records of open-ocean dust deposition fluxes are sparse. Here, we present a series of Saharan dust collected between 2015 and 2022 by dust-collecting buoys that are monitoring dust in the equatorial North Atlantic Ocean, as well as by moored sediment traps at the buoys' positions at ~21°N/21°W and ~11°N/23°W directly below the major dust Saharan-dust plume offshore northwest Africa. We present dust-flux data as well as particle-size distribution data, and make a comparison of the dust collected from the atmosphere at the ocean surface with the dust settling through the ocean and intercepted by the submarine sediment traps.See: www.nioz.nl/dust

Mineral dust plays an important role in the ocean’s carbon cycle through the input of nutrients and metals which potentially fertilise phytoplankton, and by ballasting organic matter from the surface ocean to the sea floor. However, time series and records of open-ocean dust deposition fluxes are sparse. Here, we present a series of Saharan dust collected between 2015 and 2020 by dust-collecting buoys that are monitoring dust in the equatorial North Atlantic Ocean as well as by moored sediment traps at the buoys' positions at ~21°N/21°W and ~11°N/23°W. We present dust-flux data as well as particle-size distribution data, and make a comparison of the dust collected from the atmosphere at the ocean surface with the dust settling through the ocean and intercepted by the submarine sediment traps. See: www.nioz.nl/dust

Piliostigma thonningii (Fabaceae) is a versatile medicinal plant used as a traditional remedy, especially in African countries. In the present study, ethyl acetate, methanolic and water extracts of different parts of (fruits, leaves, stem barks) P. thonningii were evaluated for their bioactive contents, enzyme inhibitory, antioxidant and antimicrobial activities. Antioxidant potentials were also displayed in various methods like phosphomolybdenum assay (0.79-5.94 mmol TE/g), radical scavenging assays (DPPH: 20.39-471.28 mg TE/g; ABTS: 42.43-654.14 mg TE/g); reducing assays (CUPRAC: 102.98-1207.42 mg TE/g; FRAP: 45.30-656.25 mg TE/g) and metal chelating activity (2.55-22.32 mg EDTAE/g). In particular, the methanolic and water extracts showed better antioxidant potential. Except for a few, the extracts were also found to act as inhibitors of enzymes such as acetylcholinesterase (2.35-5.35 mg GALAE/g), butyrylcholinesterase (0.83-13.80 mg GALAE/g), tymsinase (4.03-143.86 mg KAE/g), amylase (0.21-1.39 mmol ACAE/g) and glucosidase (3.52-7.13 mmol ACAE/g). Additionally, all the tested extracts possessed significant antibacterial (minimum inhibitory concentration (MIC) and minimum bactericidal concentration: 0.11-0.61 mg/ml) and antifungal (MIC and minimum fungicidal concentration: 0.04-0.61 mg/ml) effects. Indeed, the data garnered from the present study provides a bright scope for the advanced investigation on this particular plant possessing pharmacologically active traits. info:eu-repo/semantics/publishedVersion

Eating foods in which available starch was replaced by resistant starch (RS) causes lower glucose and insulin responses. There is insufficient evidence for the effects of RS when the total available carbohydrates content remains constant. The present study aimed to evaluate the effects of bread with a high amount of RS3, compared to control bread. The effects of RS on glycaemia, insulin response, appetite visual analogue scale (VAS) scores were examined. It was also determined the glycaemic index (GI) of both loaves of bread. In a single-blind, crossover study, 37 nondiabetic adults consumed equivalent samples of a test bread with a high amount of RS (HRS - 2.4%) or a conventional bread (REF - 0.8%), with a washout period of at least one week. Postprandial glucose and VAS scores were measured at fasting, 15, 30, 45, 60, 90 and 120 min after the meal. Insulin response was measured at fasting and 30 min. HRS bread presented a significantly lower postprandial glucose response at 60, 90 and 120 min (P ≤ 0.05). Incremental AUC glycaemia response showed significantly lower values for HRS bread (127.15 ± 71.54 mmol*min/l) as well as higher satiety scores, compared to REF bread (153.77 ± 80.38 mmol*min/l); t(36) = 2.234; P = 0.016. HRS bread showed a GI = 60 much lower than the REF bread. The higher amount of RS causes a significantly lower postprandial glucose response. These results shows that RS3 influenced the digestibility of the available starch fraction. No differences were observed at insulin response. RS is related to higher satiety scores.

Coccolithophores are among the most important calcifying pelagic organisms. To assess how coccolithophore species with different coccolith-carbonate mass and distinct ecological resilience to ocean warming will influence the “rain ratio” and the “biological carbon pump”, 1 yr of species-specific coccolith-carbonate export fluxes were quantified using sediment traps moored at four sites between NW Africa and the Caribbean (i.e., CB-20°N/21°W, at 1214 m; M1-12°N/23°W, at 1150 m; M2-14°N/37°W, at 1235 m; M4-12°N/49°W, at 1130 m). Highest coccolith-CaCO3 fluxes at the westernmost site M4, where the nutricline is deepest along the tropical North Atlantic, were dominated by deep-dwelling small-sized coccolithspecies Florisphaera profunda and Gladiolithus flabellatus. Total coccolith-CaCO3 fluxesof 371 mg m−2 yr−1 at M4 were followed by 165 mg m−2 yr−1 at the north-easternmost CB, 130 mg m−2 yr−1 at M1, and 114 mg m−2 yr −1 at M2 in between. Coccoliths accounted for nearly half of the total carbonate flux at M4 (45%), much higher compared to 23% at M2 and 15% at M1 and CB. At site M4, highest ratios of coccolith-CaCO3 to particulate organic carbon fluxes and weak correlations between the carbonate of deep-dwelling species and particulate organic carbon suggest that increasing productivity in the lower photic zone in response to ocean warming might enhance the rain ratio and reduce the coccolith-ballasting efficiency. The resulting weakened biological carbon pump could, however, be counterbalanced by increasing frequency of Saharan dust outbreaks across the tropical Atlantic, providing mineral ballast as well as nutrients to fuel fast-blooming and ballast-efficient coccolithophore species.

Mineral dust plays an important role in the ocean’s carbon cycle through the input of nutrients and metals which potentially fertilise phytoplankton, and by ballasting organic matter from the surface ocean to the sea floor. However, time series and records of open-ocean dust deposition fluxes are sparse. Here, we present a multi-year time series of Saharan dust collected by dust-collecting buoys that are monitoring dust in the equatorial North Atlantic Ocean as well as by moored sediment traps at the buoys' positions at ~21°N/21°W and ~11°N/23°W. We present dust-flux data as well as particle-size distribution data, and make a comparison of the dust collected from the atmosphere at the ocean surface with the dust settling through the ocean and intercepted by the submarine sediment traps. See: www.nioz.nl/dust

To assess the impacts of Amazon River discharge, Saharan dust deposition, N2‐fixation and mixed‐layer deepening on the biological carbon pump, sediment traps were moored from October 2012 to November 2013 at two sites in the western tropical North Atlantic (49°W,12°N/57°W,12°N). Particle exports interpreted along with satellite‐ and Argo‐float data show peak fluxes in biogenic silica (31 mg m−2d−1) and organic carbon (25 mg m−2d−1) during the fall of 2013 that were ten to five times higher than any time earlier during the year. These high export fluxes occurred in tandem with high surface chlorophyll a concentrations associated with the dispersal of the Amazon River plume, following retroflection into the North‐Atlantic‐Counter‐Current. High fucoxanthin fluxes (> 80 μg m−2d−1) and low δ15N‐values (−0.6‰) suggest a large contribution by marine diatom‐diazotrophic‐associations, possibly enhanced by wet Saharan dust deposition. During summer, the Amazon River plume resulted in high mass fluxes at 57°W that were enriched in biogenic silica but weakly influenced by diazotrophic‐associations compared to the fall event at 49°W. High carbonate‐carbon fluxes (17 mg m−2d−1) dominated a second single event at 49°W during spring that was likely triggered by mixed‐layer deepening. Rain‐ratios of BSi/Ccarb amounted to 1.7 when associated with high export fluxes linked to the Amazon River plume. Compared to an annual average of 0.3, this indicates a more efficient uptake of CO2 via the biological pump compared to when the plume was absent, hence supporting earlier observations that the Amazon River plume is important for ocean CO2 sequestration.

Mineral dust plays an important role in the ocean’s carbon cycle through the input of nutrients and metals which potentially fertilise phytoplankton, and by ballasting organic matter from the surface ocean to the deep sea floor. In addition, mineral dust feeds back on climate through many different pathways like changing the radiative balance of the atmosphere, by stimulating cloud formation, dampening hurricane formation and by changing the earth’s albedo. Because open-ocean dust-flux measurements are either based on shipboard- or sediment-trap data, they are biased by interpolation and extrapolation of point observations in space and time. Alternatively, dust-flux estimations can be made using satellite observations, but these are often hampered by the presence of clouds. For these reasons we have been studying Saharan dust along a Transatlantic transect between northwest Africa and the Caribbean, focussing on temporal and spatial variability of dust-deposition fluxes and how these are reflected in terms of dust particle size and composition. One important finding deals with the deposition of Saharan dust by rain, which seems to be an important way to make nutrients available to phytoplankton living in the surface ocean. Nutrient-release bottle experiments in ambient sea water carried out along the same transect demonstrate how wet deposition of Saharan dust increases the release of both macro- (P, Si) and micronutrients (Fe) up to an order-of-magnitude as opposed to dry deposition. Rain-amplified bioavailability of these nutrients may well be the key to increased surface-ocean productivity in the remote and oligotrophic parts of the oceans and, potentially, also continental ecosystems. See: www.nioz.nl/dust

Massive amounts of Saharan dust are blown from the coast of northern Africa across the Atlantic Ocean towards the Americas each year. This dust has, depending on its chemistry, direct and indirect effects on global climate which include reflection and absorption of solar radiation as well as transport and deposition of nutrients and metals fertilizing both ocean and land. To determine the temporal and spatial variability of Saharan dust transport and deposition and their marine environmental effects across the equatorial North Atlantic Ocean, we have set up a monitoring experiment using deep-ocean sediment traps as well as land-based dust collectors. The sediment traps were deployed at five ocean sites along a transatlantic transect between north-west Africa and the Caribbean along 12° N, in a downwind extension of the land-based dust collectors placed at 19° N on the Mauritanian coast in Iouîk. In this paper, we lay out the setup of the monitoring experiment and present the particle fluxes from sediment trap sampling over 24 continuous and synchronized intervals from October 2012 through to November 2013. We establish the temporal distribution of the particle fluxes deposited in the Atlantic and compare chemical compositions with the land-based dust collectors propagating to the downwind sediment trap sites, and with satellite observations of Saharan dust outbreaks. First-year results show that the total mass fluxes in the ocean are highest at the sampling sites in the east and west, closest to the African continent and the Caribbean, respectively. Element ratios reveal that the lithogenic particles deposited nearest to Africa are most similar in composition to the Saharan dust collected in Iouîk. Downwind increasing Al, Fe and K contents suggest a downwind change in the mineralogical composition of Saharan dust and indicate an increasing contribution of clay minerals towards the west. In the westernmost Atlantic Ocean, admixture of re-suspended clay-sized sediments advected towards the deep sediment trap cannot be excluded. Seasonality is most prominent near both continents but generally weak, with mass fluxes dominated by calcium carbonate and clear seasonal maxima of biogenic silica towards the west. The monitoring experiment is now extended, with autonomous dust sampling buoys for better quantification of Saharan dust transport and deposition from source to sink and their impact on fertilization and carbon export to the deep ocean.

Tese de mestrado, Ecologia e Gestão Ambiental, Universidade de Lisboa, Faculdade de Ciências, 2020 Submitted by Teresa Boa (tdboa@fc.ul.pt) on 2020-09-01T13:13:19Z No. of bitstreams: 1 ulfc126127_tm_Ana_Catarina_Leal.pdf: 4645395 bytes, checksum: 0a360de881a6d42b809fb479f0425c2a (MD5) Made available in DSpace on 2020-09-01T13:13:33Z (GMT). No. of bitstreams: 1 ulfc126127_tm_Ana_Catarina_Leal.pdf: 4645395 bytes, checksum: 0a360de881a6d42b809fb479f0425c2a (MD5) Previous issue date: 2020

Tropical oceans provide a benchmark for future primary productivity in increasingly warmer, stratified and nutrient-depleted waters. In this context, we assess the export fluxes of calcifying phytoplankton (coccolithophores) across the tropical North Atlantic, from upwelling affected NW Africa, via three ocean sites along 12 degrees N to the Caribbean. Sampling was undertaken by means of a spatial array of four time-series sediment traps collecting particle fluxes in two-week intervals, from October 2012 to February 2014, allowing to track temporal changes along the southern margin of the North Atlantic central gyre. Species composition and seasonal export fluxes of coccolithophores show steep gradients in two groups. Upper photic zone (UPZ) and placolith-bearing species dominated by Emiliania huxleyi and Gephyrocapsa oceanica are most abundant in the mesotrophic surface waters of the Cape Blanc upwelling system off NW Africa. They decline gradually towards the Caribbean, paralleled by increasing surface temperatures and decreasing surface chlorophyll-a. Meanwhile the abundance of lower photic zone (LPZ) species Florisphaera profunda and Gladiolithus flabellatus increase in the same direction, reaching fluxes up to 3-5 times higher in the western end of the transect compared to the UPZ flora in mesotrophic waters. Adapted to low light conditions, the LPZ species follow the geostrophic wind-forced deepening of the thermocline/nutricline westward in ever lower species diversity towards the Caribbean. Temporal changes were marked by weak seasonality in coccolith fluxes at all four sites, modulated by latitudinal migration of the Intertropical Convergence Zone (ITCZ) at the tropical sites Ml, M2 and M4, and by spatiotemporal variation in wind-forced upwelling at site CB. A seasonal mismatch was observed between LPZ and UPZ-oligotrophic taxa (i.e. Umbellosphaera spp., Rhabdosphaera spp.) vs. UPZ-opportunistic species (E. huxleyi, G. oceanica) at the western site M4 contrasting with the more similar seasonal patterns amongst all species towards site CB. We interpret this as reflecting the entire photic zone becoming increasingly nutrient enriched towards east whenever wind-forced mixing occurs due to the eastward shoaling of the thermocline/nutricline. Our synoptic observations of seasonally resolved export fluxes at four sites contribute to the spatiotemporal understanding of coccolithophore fluxes across the entire tropical North Atlantic, urging for considering phytoplankton- and carbonate production across the entire photic zone when projecting the effects of ocean warming on future primary production. NWONetherlands Organization for Scientific Research (NWO) [822.01.008] ERCEuropean Research Council (ERC) [311152] University of Bremen European UnionEuropean Union (EU) [600411, 796802] Portuguese Science Foundation (FCT)Portuguese Foundation for Science and Technology [UID/MAR/04292/2013] [SFRH/BPD/118760/2016] info:eu-repo/semantics/publishedVersion

Incubation experiments comprising Saharan dust additions were conducted in the tropical North Atlantic Ocean along an east-west transect at 12° N to study the phytoplankton response to nutrient release in oligotrophic seawater conditions. Experiments were performed at three stations (M1, M3, M4), mimicking wet and dry deposition of low and high amounts of Saharan dust deposition from two different dust sources (paleo-lake and sand dune). Dust particle sizes were adjusted to resemble dust that is naturally deposited over the ocean at the experiment sites. For wet dust deposition, the dust was pre-leached in acidified ‘artificial rainwater’ (H2SO4) for 16 to 24 hours, mimicking acid cloud processing at different pH values. Experiments were run up to eight days. Daily nutrient measurements of phosphate (PO43−), silicate (SiO44−), nitrate (NO3−) and cell abundances were performed in addition to measurements of concentrations of total dissolved iron (DFe), particulate organic carbon (POC), and dissolved inorganic carbon (DIC) at the start and at the end of the experiments. A significant initial increase and subsequent gradual decrease in PO43−, SiO44− and DFe concentrations were observed after wet dust deposition using high amounts of dust previously leached in low pH rain (H2SO4, pH = 2). Remarkably, the experiments showed no nutrient release (PO43−, SiO44− and DFe) from dry-dust addition and the NO3− concentrations remained unaffected in all (dry and wet) experiments. The prokaryotic cyanobacterium Synechococcus spp. was the most prominent picophytoplankton in all mixed layer experiments. After an initial increase in cell abundance, a subsequent decrease (at M1) or a slight increase (at M3) with similar temporal dynamics was observed for dry and wet dust deposition experiments. The POC concentrations increased in all experiments and showed similar high values after both dry and wet dust deposition treatments, even though wet dust deposition is considered to have a higher potential to introduce bioavailable nutrients (i.e. PO43−, SiO44− and DFe) into the otherwise nutrient-starved oligotrophic ocean. Our observations suggest that such nutrients may be more likely to favor the growth of the phytoplankton community when an additional N-source is also available. In addition to acting as a fertilizer, our results from both dry and wet dust deposition experiments suggest that Saharan dust particles might be incorporated into marine snow aggregates leading to similar high POC concentrations.

Relatório de Estágio do Mestrado em Gestão apresentado à Faculdade de Economia O tema “Preços de Transferência”, nos anos recentes, tem sido alvo de enorme discussão por vários agentes económicos. Tanto por ser um tema que trás consigo questões a nível económico como fiscal, tanto pelas alterações que as legislações e recomendações sobre o mesmo têm sofrido.O tema em si é constantemente alvo de discussão ao nível internacional e o caminho que se está a tomar é no sentido de cada vez mais se uniformizarem políticas entre países e de se celebrarem acordos para aumentar a transparência e facilitar o acesso a informação. Como tal as empresas cada vez mais são obrigadas a constantemente modificar e adaptar as suas políticas por forma a não pagarem multas ou se verem envolvidas em processos judiciais morosos e dispendiosos.O presente relatório tem como objeto o estágio realizado no departamento financeiro e administrativo da empresa Schaeffler Portugal e o estudo da política de preços de transferência do Grupo Multinacional em que a mesma se insere.O objetivo do estudo realizado foi o de enquadrar as políticas do Grupo Schaeffler nos standards internacionais relacionados com o tema e observar o cumprimento das regas impostas pela Lei Portuguesa.Dado que, recentemente, os referidos standards foram alvo de grandes alterações, nomeadamente devido à implementação do Plano BEPS que consequentemente levou à republicação das Recomendações da OCDE sobre Preços de Transferência, e que trouxeram consigo mudanças a nível da legislação nacional, fez-se um estudo sobre estes factos de forma a avaliar se a o Grupo mantém as suas políticas atualizadas.Foi possível concluir que o Grupo Schaeffler mantém a sua política de preços de transferência atualizada e conforme os standards internacionais, respeitando das legislações dos vários países onde atua, nomeadamente em Portugal. Também foram identificadas áreas onde o Grupo pode implementar melhorias, como no que respeita aos acordos de partilhas de custos e prestação de serviços, entre outras questões relacionadas com as atividades diárias da empresa Schaeffler Portugal. Transfer pricing, in recent years, has been a much discussed theme by a lot of economic agents. Both because of the questions it arises economically and in the tax domain and because of the updates and alterations that the legislations and guidelines about it have suffered.This theme is often subject to numerous discussion at an international level and the path that it is taking is one of policy uniformity between different countries and one of celebration of agreements to enhance transparency and to facilitate the sharing of information. Being so, companies have become forced to being constantly modifying and adapting their policies in order to don’t pay fines or be involved in court lawsuits the are very costly and time consuming.The present report is about the internship that took place at the financial and administrative department at Schaeffler Portugal and the study of the transfer pricing policy of the Multinational Group it is a part of.The object of the study was to frame the policies of the Schaeffler Group in the international standards referring the theme and perceive if those policies are in accordance with the Portuguese Law.Due to the fact that recently those standards were subject to enormous changes due to the implementation of the BEPS Action Plan, that led to the republishing of the OECD Transfer Pricing Guidelines, which brought changes to the national laws, those facts were studied in order to evaluate if the Group keep its policies up to date.It was possible to conclude that the Schaeffler Group keep its transfer pricing policy updated and in accordance with the international standards, keeping in mind the different rulings of the various countries where it operates, namely in Portugal. There were identified areas in which there could be made improvements, like the cost contribution agreements and the provision of services, among other issues regarding the daily activities of Schaeffler Portugal.

Regardless of the advances that technology and instructional design have brought, there is lack of information regarding an emergent topic of the 21stcentury business: informal learning. Academic research does not fully cover its state, and much less considers the Portuguese reality. Following this line of reasoning, the purpose of this dissertation is to address informal learning, withdrawing and clarify "How managers in companies operating in Portugal face informal learning". The study follows a qualitative method, with a content analysis of eleven interviews to managers from companies of diverse industries. The main results are presented in the form of four streams of analysis: "concept", "antecedents", "organizational supporting methods" and "outcomes". The findings show that, more than a modality of training, informal learning is a journey which shapes knowledge, through a combination of diversified learning tools and experiences. Results highlight that managers are aware of its importance and are giving way to disruptive pedagogical events in their respective companies, to ensure that employees "reflect" on their own learning needs, access key "organizational" resources and rely on "peer-to-peer interaction" to expand their knowledge. The results suggest that informal learning boosts communication and increases motivation and engagement level, contributing to improved organizational performance. The study finalizes with guidelines to reshape and complement traditional formal training programs, established in most organizations. These practical implications delineate a structure and advocate informal learning, delving into its design. Apesar dos avanços tecnológicos e da engenharia pedagógica tornaram possíveis, existe pouca informação relativamente a um tema emergente do contexto empresarial do século XXI: aprendizagem informal. A investigação académica não aborda por completo o seu estado de arte, e tampouco a realidade portuguesa. Assim, o propósito desta é abordar o tema da aprendizagem informal e clarificar "Como é que os gestores nas empresas a operar em Portugal encaram a aprendizagem informal". Este estudo segue o método qualitativo, com a análise de conteúdo de onze entrevistas a gestores, de empresas a operar em indústrias diversas. Os resultados principais são apresentados na forma de quatro linhas de análise: "conceito", "antecedentes", "métodos organizacionais de apoio" e "consequências". Os resultados demonstram que, mais do que uma modalidade de formação, a aprendizagem informal é uma jornada que reconfigura a aprendizagem, através da combinação de diversas técnicas e experiências de aprendizagem. Os resultados destacam que os gestores estão cientes da importância desta vertente da aprendizagem e estão a abrir caminho a eventos pedagógicos disruptivos, que asseguram que os colaboradores "refletem "acerca das suas necessidades de aprendizagem, acedem a "recursos organizacionais" chave e contam com a "interação com os pares" para alargar o seu conhecimento. Os resultados sugerem que a aprendizagem informal acelera a comunicação, aumenta a motivação e o nível de comprometimento, contribuindo para a melhoria do desempenho organizacional. O estudo conclui com linhas guia para moldar e complementar os programas tradicionais de aprendizagem formal, estabelecidos na maioria das empresas. Estas implicações práticas visam delinear uma estrutura e suportar a aprendizagem informal, investigando a sua conceção.

Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition and seasonal patterns were determined in two sediment trap moorings in the open equatorial North Atlantic (M4 at 12° N 49° W and M2 at 14° N 37° W), which collected settling particles synchronously in successive 16-day intervals from October 2012 to November 2013, at 1200 m water depth. The two trap locations show a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage throughout the monitored year. Species fluxes were yearlong dominated by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus), but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241 × 107 coccoliths m−2 d−1 (117 × 107 to 423 × 107 coccoliths m−2 d−1) at station M4, compared to only 66 × 107 coccoliths m−2 d−1 (25 × 107 to 153 × 107 coccoliths m−2 d−1) at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, although most UPZ species also contributed higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. In addition, we found two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi indicating a fast response to nutrient-enrichment of the UPZ, probably by wind-forced mixing, whereas increased fluxes of G. oceanica and E. huxleyi in October/November 2013 coincided with the occurrence of Amazon River affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust flux peaks we propose a scenario where atmospheric dust also provided fertilizing nutrients to this area. Enhanced surface buoyancy associated to the river plume indicates that the Amazon acted not only as a nutrient source, but also as a surface density retainer for nutrients supplied from the atmosphere. Still, lower total coccolith fluxes during these events compared to the maxima recorded in November 2012 and July 2013 indicate that transient productivity by opportunistic species was less important than background tropical productivity in the equatorial North Atlantic. This study illustrates how two seemingly similar sites in an open-ocean tropical setting actually differ greatly in ecological and oceanographic terms, and provides valuable insights into the processes governing the ecological dynamics and the downward export of coccolithophores in the tropical North Atlantic.

Massive amounts of Saharan dust are blown from the African coast across the Atlantic Ocean towards the Americas each year. This dust has, depending on its chemistry, direct and indirect effects on global climate including reflection and absorption of solar radiation as well as transport and deposition of nutrients and metals fertilizing both ocean and land. To determine the temporal and spatial variability of Saharan dust transport and deposition and their marine environmental effects across the equatorial North Atlantic Ocean, we have set up a monitoring experiment using deep-ocean sediment traps as well as land-based dust collectors. The sediment traps were deployed at five ocean sites along a transatlantic transect between northwest Africa and the Caribbean along 12⁰ N, in a down-wind extension of the land-based dust collectors placed at 19⁰ N on the Mauritanian coast in Iwik. In this paper, we lay out the setup of the monitoring experiment and present the particle fluxes from sediment trap sampling over 24 continuous and synchronised intervals from October 2012 through to November 2013. We establish the temporal distribution of the particle fluxes deposited in the Atlantic and compare chemical compositions with the land-based dust collectors propagating to the down-wind sediment trap sites, and with satellite observations of Saharan dust outbreaks. First-year results show that the total mass fluxes in the ocean are highest at the sampling sites in the east and west, closest to the African continent and the Caribbean, respectively. Element ratios reveal that the lithogenic particles deposited nearest to Africa are most similar in composition to the Saharan dust collected in Iwik. Down-wind increasing Al, Fe and K contents suggest a downwind change in the mineralogical composition of Saharan dust and indicate an increasing contribution of clay minerals towards the west. In the westernmost Atlantic, admixture of re-suspended clay-sized sediments advected towards the deep sediment trap cannot be excluded. Seasonality is most prominent near both continents but generally weak, with mass fluxes dominated by calcium carbonate and clear seasonal maxima of biogenic silica towards the west. The monitoring experiment is now extended with autonomous dust sampling buoys for better quantification Saharan dust transport and deposition from source to sink and its impact on fertilization and carbon export to the deep ocean.

Dissertação de Mestrado Integrado em Arquitetura, com a especialização em Urbanismo, apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Mestre. Submitted by Pilar Lago (mpilar@fa.utl.pt) on 2016-12-12T11:21:20Z No. of bitstreams: 1 Ines Ferreira - Requalificação de Espaços Suburbanos de Exclusão.pdf: 113438218 bytes, checksum: b354a76db876237a4f6a14326863b82b (MD5) Made available in DSpace on 2016-12-12T11:21:20Z (GMT). No. of bitstreams: 1 Ines Ferreira - Requalificação de Espaços Suburbanos de Exclusão.pdf: 113438218 bytes, checksum: b354a76db876237a4f6a14326863b82b (MD5) Previous issue date: 2016-07

Tese de mestrado, Biologia Molecular e Genética, Universidade de Lisboa, Faculdade de Ciências, 2015 Submitted by Teresa Boa (tdboa@fc.ul.pt) on 2016-02-15T11:25:54Z No. of bitstreams: 1 ulfc116103_tm_Ana_Catarina_Marques.pdf: 1563152 bytes, checksum: f8f9b6097a30d292b14c3be780ef5e97 (MD5) Made available in DSpace on 2016-02-15T11:26:02Z (GMT). No. of bitstreams: 1 ulfc116103_tm_Ana_Catarina_Marques.pdf: 1563152 bytes, checksum: f8f9b6097a30d292b14c3be780ef5e97 (MD5) Previous issue date: 2015