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Abstract The research was conducted as a part of the phase III of the KEEP(Kuroshio Edge Exchange Processes)program. Two strings of sediment traps were deployed simultaneously: one near the outlet of North Mien-Hua Canyon (T15), and the other at the south rim of the South Okinawa Trough (T16). The purposes are to collect settling particulates at various depths for the studies of temporal and spatial variations of the particulate flux, 210Pb activity, 210Pb flux and size distribution. The particulate fluxes showed synchronous variations among the traps deployed at different depths of the same site. In general, the particulate flux in the marginal sea areas increases with depth but the maximum values may be at the mid-depth rather than at the deepest trap and remain so for the entire mooring period as observed at T15 and T16. Unusually high particulate fluxes could occur within the same period, probably reflecting an episodic event, such as typhoon or rain storm. 210Pb activity measured from different depths at T15 and T16 increases generally with depth along with the increase of the particulate flux toward the bottom. The temporal variation of 210Pb activity is generally smaller than that of the particulate flux in terms of relative amplitude. At the outlet of the canyon, T15, the temporal mean particulate flux of each trap ranged from 0.16 to 3.3 g/m2/d(a factor of ~ 20), while the mean 210Pb activity of each trap varied from about 98 to 168 dpm/g. At T16 located at the south rim of the South Okinawa Trough, the temporal mean particulate flux ranged from 0.06 to 5.7 g/m2/d(a factor of ~ 100), while the mean 210Pb activity varied from 82 to 192 dpm/g. The particulate 210Pb flux was smaller at T15 than at T16 because T15 has smaller particulate flux. The trapped particulates in the canyon(T1-T3) are mostly silt and sand, while the particulates collected from the Okinawa Trough(T15, T16) are mainly silt and clay. The 210Pb activity of the former is much lower than that of the latter, indicating the enrichment of 210Pb on the fine particulates. As the fine-grained particulates away from landmass have longer residence time in the ambient water, they can scavenge 210Pb more effectively.

This study explored the effects of seasonal variability on the geochemistry of sinking pthesiss and on the nitrogen cycle of the Cariaco Basin. Pthesis fluxes were measured at the base of the euphotic zone (the depth of 1% of photosynthetically active radiation - PAR) with drifting sediment traps during months of upwelling and non-upwelling regimes from March 2007 to November 2009. Flux estimates were analyzed in the context of seasonal variations in sea surface temperature, primary productivity, and chlorophyll a concentrations using data generated by the CARIACO Time-series Program as well as satellite data. Additionally, nine years (1996-2000 and 2004-2007) of nutrients, phytoplankton taxonomy and δ15N of sinking pthesis data within the twilight zone (225 m) from the CARIACO Time-series Program were examined. Results showed that the flux of organic matter responded to changes in surface chlorophyll a but not to primary production. Sinking organic matter decreased by an order of magnitude from the base of the euphotic zone to the oxic-anoxic interface; most of the organic matter produced in surface waters was remineralized before leaving the upper 50-100 m. Lithogenic material often represented a large fraction of the flux. Isotopic analyses showed that 13C/12C ratios of sinking organic carbon were enriched (~-19‰) during the upwelling period and depleted during relaxation (~-23‰). This reflects seasonal changes in inorganic carbon utilization by phytoplankton and suggests that the δ13C of organic carbon in Cariaco sediments can be used as a proxy for carbon fixation by primary producers. The δ15N of the settling flux was influenced by the strength of the upwelling and the presence of the nitrogen fixer Trichodesmium thiebautii in the basin in different seasons; the 15N/14N ratio of sinking nitrogen reflects both imported and local nitrogen fixation signals. This result argues against previous interpretations of the δ15N from the basin's sedimentary record, which suggested that the nitrogen isotopic composition of flux is influenced by denitrification at the oxic-anoxic interface. Dissolved gas samples from the Cariaco eastern and western sub-basins from September 2008 (non-upwelling) and March 2009 (upwelling) were studied to assess the production of biogenic nitrogen gas through mass spectrometric N2/Ar ratiometry. Excess nitrogen gas indicated that upwelling affects the intensity of denitrification at the oxic-anoxic interface. In four of the six stations the concentration of biogenic nitrogen gas at the oxic-anoxic interface was 2.7-6.1 µM N higher during the upwelling period than during the relaxation season (p< 0.001), implying that denitrification in the basin was stimulated by the vertical flux of organic matter and/or the ventilation of the oxic-anoxic interface by oxygenated and nutrient-rich intermediate Caribbean waters.

This report aimed to investigate how chlorophyll-concentrations (Chl-a) in the water column and varved sediments were affected by changes in air temperature and precipitation and consequently how climate change will affect the sedimentation and productivity in boreal aquatic ecosystems. VRS (visible-reflectance-spectroscopy) was used to asses Chl-a and its derivates in sediment trap samples between 2002-2021 and in a series of freeze cores (1979-2021) from lake Nylandssjön, with annually laminated sediments. In order to evaluate how weather and climate change affected the sedimentation and productivity in the lake the results were compared with meteorological data from SMHI (Swedish Meteorological and Hydrological Institute) and Chl-a data from seperate depths in the water column. The results indicate that the majority of the yearly sedimentation occur either in May or June, where a higher cumulative amount of precipitation in May lead to a higher sedimentation rate in May (r=0,49; p=0,03). The amount of precipitation in spring also had a significant impact on the primary production in spring and summer (r=0,59; p=0,01; r=0,73; p=0,002). Water column Chl-a and spectrally inferred Chl-a in sediments show similar trends in concentrations with deeper water sampling, however, water column Chl-a displayed significant differences in values between various depths (p=0,0004). Consequently, climate change will much likely increase the productivity of boreal aquatic ecosystems within years and the amount of sedimentation that occurs between years due to higher temperatures. An increased amount of precipitation will also enhance the primary productivity and the transportation of allochthonous- and minerogenic material to the lake.

Sediment is one of the leading non-point source pollutants in the U.S and has detrimental effects on biological communities such as aquatic communities; human use such as recreation; and natural processes such as flood water storage. For silvicultural operations, the majority of sediment is produced from erosion on highly disturbed areas, such as skid trails, haul roads, and log landings. Erosion from silvicultural activities not only has the potential to introduce sediment into waterways but can also decrease site productivity through the removal of topsoil. In order to minimize erosion from silvicultural operations, forestry Best Management Practices (BMPs) have been developed, but efficacies of various BMP options are not well documented. This study evaluated five closure and cover BMPs for the control of erosion on bladed skid trails through both field based measurements with sediment traps and soil erosion modeling. The erosion models used were the Universal Soil Loss Equation for Forestry (USLE – Forest), the Revised Universal Soil Loss Equation version 2 (RUSLE2), and the Water Erosion Prediction Project for Forest Roads (WEPP – Forest Roads). Erosion model predictions were also regressed against field based results to determine accuracy. The bladed skid trail BMP treatments evaluated were: 1) water bar only (Control); 2) water bar and grass seed (Seed); 3) water bar, grass seed, and straw mulch (Mulch); 4) water bar and piled hardwood slash (Hardwood Slash); and 5) water bar and piled pine slash (Pine Slash). Field based results show that the Control treatment was the most erosive (137.7 tonnes/ha/yr), followed by the Seed treatment (31.5 tonnes/ha/yr), Hardwood Slash treatment (8.9 tonnes/ha/yr), Pine Slash treatment (5.9 tonnes/ha/yr), and finally the Mulch treatment was the most effective erosion control technique (3.0 tonnes/ha/yr). Model accuracy results show that RUSLE2 performed the best overall. Both USLE – Forest and WEPP – Forest Roads under predicted values on the Control treatment, where erosion rates were very high. WEPP – Forest Roads under predicted these values the most. All models generally show that the Control was the most erosive followed by the Seed, Hardwood Slash, Pine Slash, and Mulch treatments. / Master of Science

Nos connaissances et notre compréhension de la dynamique sédimentaire des plages macrotidales sont encore limitées de nos jours en raison d'un manque de données lié à la plus faible proportion de ces plages à l'échelle mondiale. Trois plages macrotidales à barres et à bâches du littoral de la Côte d'Opale dans le Nord de la France ont été choisies pour mener cette étude. Elle se base sur trois approches différentes visant à caractériser (1) le régime tidal et les conditions hydrodynamiques, (2) la morphologie de la zone intertidale et (3) les flux sédimentaires longitudinaux (FL) et transversaux (FC) dans diverses conditions tidales et énergétiques. Le transport a été mesuré dans la zone proche du déferlement à l’aide de pièges à sédiment de type Kraus (1987) permettant de caractériser le débit solide à plusieurs niveaux au dessus du fond au cours de conditions d'agitation faibles à modérées (Hs < 1 m). Malgré une uniformité des flux le long de la plage, les phénomènes de vidange des bâches par l’intermédiaire de chenaux perpendiculaires au trait de côte permettent l’introduction de volumes de sédiment significatifs, augmentant localement le FL. La distribution des flux à travers l’estran présente, quant à elle, une décroissance nette du bas de plage vers le haut de plage. Les mesures simultanées de FL et de FC ont démontré que le FC dirigé vers le haut de plage et la résultante du FC sont dans la plupart des cas supérieurs aux FL en raison de la plus forte intensité des vitesses de courant oscillatoire. Ces résultats mettent en évidence des mouvements significatifs de volume de sable à travers la zone intertidale à l’échelle de la mesure, ce qui influence fortement la morphodynamique de la plage. L’ensemble de la zone intertidale est toutefois apparue relativement stable, avec des changements plus significatifs à court terme qu'à plus long terme. Les mesures de transport ont permis de mettre en lumière le rôle fondamental des bâches dans la dynamique des plages macrotidales. Ces dépressions inter-barres sont en effet responsables de la canalisation du sédiment le long du rivage, limitant ainsi les transports sédimentaires transversaux et par conséquent la migration des barres intertidales. Il est vraisemblable que le temps de résidence et l'intensité des processus hydro-sédimentaires jouent un rôle prépondérant dans la dynamique des barres intertidales. Les mesures ont également été comparées avec plusieurs estimations du transport sédimentaire issues de modèles numériques et morphodynamiques. Bien que les flux calculés surestiment en général le transport mesuré, certaines formules semblent plus adaptées pour déterminer le FL dans la zone de levée. / Our knowledge and understanding of the sediment dynamics of sandy macrotidal beaches is still limited by a lack of data from these macrotidal environments. This limitation is due to the relatively small proportion of macrotidal coasts in the world. Three sandy beaches on the coast of Northern France were chosen to conduct this study. Three scientific approaches were used: 1) characterization of tidal and waves energy conditions using wave and current meters deployed on the foreshore; 2) beach morphology survey and 3) estimation of longshore (FL) and cross-shore (FC) sediment transport using streamer traps similar to those designed by Kraus (1987). Sand transport was measured about 1 m water, next to the breaker zone and either in the shoaling zone or in the surf zone; under low to moderate waves energy conditions (Hs < 1 m). In spite of a low longshore variability in sediment transport due to a high degree of hydrodynamic uniformity along the shore, runnel drainage can locally increase sediment transport rates. Cross-shore distribution appeared to be more variable as sediment transport decreased from the lower to the upper part of the beach. Onshore, offshore and longshore sediment transport measured simultaneously showed that under various energetic conditions, FC appeared to be generally higher than FL. Although net littoral drift is directed towards the Belgian coast, these results suggest that significant volumes of sand move across the intertidal zone. These significant volumes of sand most likely have a strong influence on the morphodynamics of the beach. Daily topographical survey has shown little morphological variations while sediment transport rates appeared very variable and very significant, especially during the highest wave energy conditions. Sediment transport measurements across the foreshore highlight the important role played by inter-bar troughs in the morphodynamics of macrotidal beaches. Higher bed roughness in these depressions is responsible for an increase in sediment resuspension through the water column. Suspended transport is therefore favoured in troughs and hinders the cross-shore sediment transport, which is responsible for the bar migration across the intertidal zone. Morphological changes are dependent of the time residence of the hydrodynamic zones, but the morphodynamics of the intertidal bars appear to be strongly controlled by the amplitude of the incident waves. FL were also compared with calculated data computed using from numerical and morphodynamic model. Although computed transport rates are generally higher than in situ measurements, it appears that some formulae provide better estimate of FL, especially in the shoaling zone

Wetlands within South Africa are an important source of water and nutrients necessary for biological productivity and often the survival of the local people. In a country where the rural communities depend on wetlands for their day to day provision of water, food and materials it has become necessary to understand the functions within wetland systems, so that proper conservation measures can be applied in order to protect and ensure the sustainable use of wetlands. Due to the fact that South Africa has a semi arid climate, thereby affecting the availability of water it is sensible that studies are under-taken in which, more is explored about the water resources, the protection as well as the sustainable use of the wetlands within the region. Despite the fact that the total area which wetlands cover in South Africa is relatively small, the functions which they provide is of fundamental magnitude not only to wildlife but also as an essential part of the human life support system. Wetlands have the ability to regulate regional flow regimes and are often situated in areas of impeded drainage, which may contribute to the regulation of water. It is thus plausible that if headwater/palustrine wetlands are destroyed, many of the streams and rivers which under normal circumstance are perennial, would not only become non- perennial but the consequence of a drought would be far more severe, as well as increasing the risk in flood damage further down the river. In Giants Castle Game Reserve, situated in the KwaZulu-Natal Drakensberg, several palustrine wetlands where studied to identify the geomorphic attributes which contribute to the origin and maintenance of these wetlands. An added motive for the study was the fact that, according to Ramsar, one of the reasons for conserving the Drakensberg wetlands is to ensure the maintenance and production of water quality to KwaZulu-Natal. Seven wetlands within the Boesmans river upper catchment were identified and studied. Soil investigations were undertaken in an effort to determine the driving forces behind the origin and maintenance, as well as to improve the understanding relating to the functioning of the wetlands. The geomorphic attributes which were identified as being important to the genesis and maintenance of wetlands were found to be the following: low relief, soil piping within wetlands, sediment trapping ability of wetlands, the surface roughness of wetlands, channeling within wetlands, organic matter accumulation as well as geological barriers within wetland system. The adaptability of Longmore’s (2001) Hydro-Geomorphic classification to different catchment areas was also tested and was found suitable for these wetlands, although the influence of piping on wetlands evidently requires further investigation and incorporation into classifications. / Dissertation (MA)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / MA / Unrestricted

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-05-12T17:27:18Z No. of bitstreams: 1 COMPOSIÇÃO BIOGÊNICA E FLUXOS DO MATERIAL PARTICULADO NA PLATAFORMA CONTINENTAL DE CABO FRIO, BRASIL EXPERIMENTOS COM ARMADILHAS DE SEDIMENTOS DURANTE FUNDEIOS DA PRIMAVERA DE 2010 E OUTONO DE 2011.pdf: 4380478 bytes, checksum: a9469131095e97d77020eb0a649c8509 (MD5) / Made available in DSpace on 2017-05-12T17:27:18Z (GMT). No. of bitstreams: 1 COMPOSIÇÃO BIOGÊNICA E FLUXOS DO MATERIAL PARTICULADO NA PLATAFORMA CONTINENTAL DE CABO FRIO, BRASIL EXPERIMENTOS COM ARMADILHAS DE SEDIMENTOS DURANTE FUNDEIOS DA PRIMAVERA DE 2010 E OUTONO DE 2011.pdf: 4380478 bytes, checksum: a9469131095e97d77020eb0a649c8509 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / O sistema de ressurgência de Cabo Frio (SRCF) é reconhecido como uma das áreas mais produtivas do leste da costa sul - americana, embora o papel do aporte continental como fertilizador das águas da plataforma continental tem sido negligenciado. Este estudo r elata dois experimentos de armadilhas de sedimentos localizados a - 50 m de profundidade (AS) e a - 100 m (AF) sobre a plataforma continental de Cabo Frio (profundidade local - 140 m, 23◦ 36' S - 041◦ 34' O). As armadilhas foram programadas para capturar mate rial particulado durante o processo de sedimentação em dois experimentos distintos, o primeiro no final da primavera de 2010 (por um período de 45 dias com 3 dias de integração para cada garrafa) e no outono de 2011 (por um período de 90 dias com 7 dias de integração para cada garrafa). Neste estudo são abordados os fluxos e a composição biogênica do material particulado (carbono orgânico, nitrogênio, δ 13 C e δ 15 N determinada por EA - IRMS), em conjunto com atribuições de sua provável origem. O fluxo de massa total capturado pelas armadilhas variou amplamente (1,06 - 52,7 mg.m - 2 .dia - 1 ). O fluxo de carbono orgânico particulado mostrou flutuações menores (0,33 - 5,37mgOC.m - 2 .dia - 1 ) onde os fluxos médios foram maiores para as armadilhas de fundo. Os resultados das correlações entre fatores isolados, tais como temperatura, divergência dos ventos, escoamento perpendicular e paralelo, e o fluxo de massa total não foram significativos, o que sugere que o fluxo de partículas não poderia ser explicado pelo controle de um único fator, mas pela interação de eventos na plataforma continental. Os resultados também indicam um forte componente de transporte advectivo na plataforma continental e, que as partículas capturadas pelas armadilhas em Cabo Frio são derivadas de uma mis tura de fontes que são influenciadas por múltiplos processos físico - químicos e oceanográficos. Partículas de origem marinha foram capturadas durante a maior parte do tempo, mas com contribuição de material continental, especialmente na armadilha do fundo, sugerindo uma possível origem em processos de sedimentação e ressuspensão de material continental na plataforma continental, provavelmente produto da degradação costeira ou de aportes fluviais. Desta forma o SRCF é um sistema altamente dinâmico e compartim entalizado, onde a formação, transporte e a dispersão de partículas são controlados por múltiplos processos onde o aporte continental desempenha um importante papel / ABSTRACT The Cabo Frio upwelling system (SRCF) is recognized as one of the more productive area of the Eastern South America n coast, although the role of the continental contribution as wate r fertilizer of the shelf has been neglected. This study reports two experiments of sediment traps positioned at 50 m (AS) and 100 m (AF) depth over the continental shelf of Cabo Frio ( local depth 140 m , 23 ◦ 36 ' S - 041 ◦ 34 ' W). The traps were scheduled to capture particulate matter during the sedim entation process in two experiments , the first in the late spring of 2010 (for a period of 45 days with 3 days of integration for each bottle ) and t he second in autumn of 2011 (for a period of 90 days with 7 days of integration for each bottle ). This work addresses the flux and the composition of biogenic particulate matter (organic carbon, nitrogen, δ 13 C and δ 15 N determined by EA - IRMS) with the attributes of their possible origin . The total mass flux captured by the traps varied widely (1.06 - 52.7 mg. m - 2 . day - 1 ). The flux of particulate organic carbon showed smaller fluctuations (0.33 - 5, 37mgOC. m - 2 . day - 1 ), where the mean flux at the bottom sediment traps was higher . The results of the correlations between isolated factors, such as temperature, divergent winds, cross - shelf and long - shelf flux, and the total mass fl ux were non significant, suggesting that the fl ux of particles could not be explained by the control of a singl e factor but b y the interaction of events on the continental shelf. P articles with m arine origin were captured during most of the time, but with the con tribution of continental material especially at the bottom trap, suggesting a possible origin in the sedimentation and res s uspension processes of contine ntal material in the shelf, probably the product of coastal degradation or river inputs. Thus , the SRCF is a highly dynamic and compartmentalized system , where the formation, transpor t and dispersion of particles are contr olled by multiple processes where continental input play an important role