Geological Oceanography

Pada praktikum mengukur kecepatan arus, langkah pertama yang perlu dilakukan adalah mempersiapkan alat dan bahan, seperti botol plastik, tali atau benang, stopwatch, serta melakukan pengukuran badan sungai. Adapun langkah-langkahnya adalah sebagai berikut: 1. Penentuan Jarak Ukur jarak antara titik A dan titik B sejauh 10 meter sebagai lintasan percobaan.

Teluk Jakarta merupakan kawasan yang terkena dampak langsung dari berbagai aktivitas kota metropolitan DKI Jakarta sehingga menjadi tempat bermuaranya berbagai senyawa polutan di wilayah DKI Jakarta. Adanya kegiatan reklamasi juga turut menambah beban Teluk Jakarta. Tujuan dari penelitian ini adalah menjelaskan kondisi terkini perairan Teluk Jakarta melalui sebaran kualitas air pasca kegiatan reklamasi. Penelitian ini dilakukan dengan membandingkan data kualitas air pada bulan Oktober 2018 dimana saat pasca reklamasi dengan penelitian kualitas air sebelumnya pada bulan September 2014 pada saat sebelum adanya kegiatan reklamasi di Teluk Jakarta. Hasil penelitian ini menunjukkan kondisi suhu berkisar 28-31 ºC, salinitas berkisar 25,42-35 psu, derajat keasaman (pH) berkisar 7,2-8,6, partikel tersuspensi (TSS) berkisar 1-216 mg/l, Cu Terlarut berkisar 0-0,092 mg/l, dan Zn berkisar 0-0,280 mg/l. Sedangkan penelitian pada sebelumnya pada saat pra-reklamasi menunjukkan suhu berkisar 28,9-3...

In this work, we provide an extensive inventory of Pb and Nd radiogenic isotopes in surface sediments from the Southwestern Atlantic margin, aiming to interpret the role played by ocean circulation in sediment distribution. There are latitudinal trends for Pb and Nd isotopes, reflecting the different current systems acting on the margin. The utilization of sediment fingerprinting allowed us to associate the isotopic signatures to the main oceanographic forcings in the area. We recognized differences between the Nd and Pb sources for the sediments to the Argentinean shelf, carried by the Subantarctic Shelf Water, and slope, transported by deeper flows. Sediments from Antarctica extend up to the Uruguayan margin, carried by the Upper-and Lower Circumpolar Deep Water. Our data confirm that, for shelf and intermediate (up to 1,200 m water depth) areas, the transfer of sediments from the Argentinean margin to the North of 35 o S is limited by the Subtropical Shelf Front and the recirculated Antarctic Intermediate Water. On the southern Brazilian margin, it is possible to recognize the northward influence of the Río de la Plata sediments carried by the Plata Plume Water. This influence is limited by the southward flow of waters transported by the Brazil Current. Finally, we propose that the Subtropical Shelf Front and the Santos Bifurcation act as boundaries of geochemical provinces in the area. Finally, a qualitative model of sediment sources and transport is provided for the Southwestern Atlantic margin. Long half-life radiogenic elements, such as Sr, Pb, and Nd, are efficient tools in the study of sediment transport in continental margins. utilized Sr and Nd isotopes to trace the main pathways of riverine suspended sediments on the

The Uruguayan Continental Margin is located in a strategic location of great relevance to understand the dynamics of the regional and global climate and to study the sedimentary processes. The Río de la Plata represents the largest fluvial discharge of the Southwest Atlantic (23.000 m 3 /s of water and 57.000.000 m 3 /year of sediment for the South Atlantic Ocean). The sub-surface and deep circulation are characterized by the confluence of water masses with contrasting thermohaline characteristics that determine the formation of well-marked hydrological fronts. In the continental shelf, this characteristic is represented by the Subtropical Shelf Front, as a shallow extension of the Brazil-Malvinas Confluence that occurs in deep water off the shelf. Although the knowledge of the regional circulation is acceptable, there are significant gaps in the knowledge related to the influence of this complex hydrological system on sedimentation processes. The objective of this work is to synthesize the present knowledge about the morphosedimentary characteristics of the Uruguayan Continental Margin and the processes involved in its formation. It also aims to discuss some knowledge gaps that are the subject of current research in the region. The knowledge reflects the scientific-technological evolution at a global level that is translated in the increase of recent works on the continental slope. Nowadays, most of the available information is associated with the inner shelf and upper slope. Starting from the basis of the close relationship between bathymetry and sedimentological distribution it is clear that efforts should be concentrated on the better understanding of the interaction between the shelf and the slope. The scientific knowledge regarding sedimentology and geochemistry along the Uruguayan Continental Margin is still, scarce and heterogeneous. However, it indicates complexity in the sedimentary coverture present both in the continental shelf and slope. The Uruguayan Continental Margin can be considered as an in situ laboratory to improve the understanding of the influence of oceanic hydrodynamics on the margin configuration, a key point to achieve better paleoceanographic interpretations. In this sense, due to the complexity of both modern hydrology and morphological configuration of the margin, it would be interesting to understand the relative importance of the control of each environment on surface sedimentation. A better understanding of the processes that link the near bottom circulation and continental slope features is needed. At the same time, this will allow deepening a new field of research in Uruguay, considering the joint and interrelated vision between sedimentary and oceanographic processes.

This study has mainly evaluated the temporal variation of hydrographic properties, suspended particulate matter (SPM), dissolved oxygen (DO) and circulation during complete tidal cycles (13 hours) along the São Marcos Estuarine Complex (SMEC), in different rainfall regimes. Data were acquired in two moorings in SMEC: in the north (M-I) and south (M-II), during the rainy (February), transition (June) and dry (November) seasons of 2017. The thermohaline structure and DO data were measured with a CTD (EXO2, YSI, Ohio, USA), the estuarine circulation was measured with a 500 kHz ADCP (Sontek, YSI, CA, USA) and the water samples were collected with a Niskin bottle on the surface and about 1 meter above the bottom for the analysis of the SPM. The velocity profiles of the along-channel component (u) presented a bidirectional flow, with a small predominance of ebb (u > 0) between flood currents (u < 0). Generally, the (M-I) presented average values higher than the (M-II), with the means in (M-I) ranging from -0.87 to 0.96 m s -1 , while (M-II) presented mean values of -0.60 to 0.71 m s -1 . The thermohaline structure showed a vertical quasi-homogeneity behavior and a small difference between the moorings (M-I and M-II) over the three campaigns. Temperatures varied between 27.8 to 30.5 °C, salinities ranged between 16.0 to 35.5 g kg -1 and sigma-t ranged from 7.63 to 22.49 kg m -3 . The thermohaline indexes suggest the presence of two water masses, a Coastal Water (CW) during the rainy and dry seasons, whereas during the end of the rainy season was observed the presence of a River Water (RW). High concentrations of SPM (>1000 mg l -1 ) were observed in the region, with higher mean values than 230 mg l -1 over the 13 hours collected. The highest concentrations of SPM were observed in the dry season and near the bottom. The dissolved oxygen maintained a high level (DO > 190 µmol kg -1 ), despite the high SPM values found in the region, which are within the minimum limits established by the Brazilian government's regulatory agency (CONAMA). The Richardson layer number indicated a vertical instability condition throughout the SMEC, which corroborates the Potential Energy Anomaly (7.0x10 -6 a 1.1x10 -5 J m -3 s -1 ). The estuarine system was classified as type 1a (well-mixed and poorly stratified estuary), except the (M-I) performed in the dry season, which was classified as 2a (partially mixed and with weak vertical stratification). The dominant components governing the salt transport were the river discharge (2,33 to 41,06 kg m -1 s -1 ), the Stokes drift (-35,95 to -0,40 kg m -1 s -1 ) and the tidal currents (-6,05 to 2,04 kg m -1 s -1 ). River discharge was the main salt export mechanism, while Stokes drift was the main salt import mechanism in the region, presenting a contrary direction than expected. The present study represented a great step towards the understanding of the changes that occur in hydrodynamic and materials transport in macrotidal estuaries located in the Amazon Semiarid interface.

The quantitative assessment of the vulnerability of the Nile Delta coast of Egypt to the impacts of SLR and land subsidence is presented the answer for the following questions; analysing the risks, ranking the vulnerability and suggesting adaptation measures. Determine the social and biophysical vulnerability demonstrates the asymmetrical impacts of the SLR on the Mediterranean coast of Egypt, select areas at risk in Al Behairah governorate. Geographic information system (GIS) and Remote sensing (RS) techniques are powerful tool for handling and organized spatial information that can help to assess the ranges of vulnerability ranking for the study area. Geostatistical analysis using ArcGIS 9.3 of the studied governorate indicated that large parts of their coastal areas subject to be lost and buried under sea water by the year 2100. The study revealed that the risk degree is moderate to high (35-60%). Field study shows that SLR is the more extensive criterion affecting the northern Nile Delta region. For examples, the rise of Sea level leads to death of palm trees in Rashid and increases the chemical weathering of historical archaeological sites. In addition to, the ground water table level instability increases the distortion and inclination of building and infrastructure.

Evolução histórica da ocupação da linha de costa na França (Baía de Biscaia) e Brasil (Rio de Janeiro) diante da vulnerabilidade e dos riscos à erosão costeira (séculos XIX a XXI) L'évolution historique de l'occupation des littoraux français (golfe de Gascogne) et brésilien (Rio de Janeiro) face à l'érosion des côtes, aux risques et à la vulnérabilité (19e-20e siècles

Natural beaches often present a breaker bar that significantly affect physical phenomena like, for example, wave transformation, wave reflexion, energy dissipation due to breaking and wave reforming into the trough region. These transformations are associated to nonlinear wave modifications. In this work the oscillatory flow near the bottom of barred beaches is characterised. To achieve that purpose, the data obtained during two experiments were examined and processed: the data from a large-scale laboratory experiment carried out at the wave flume of the Polytechnic University of Catalonia (Barcelona, Spain) and the data from a nearshore field experiment, denoted by DUCK94, performed in

Detailed morphometric analysis of the Bor River basin in Amravati district has been attempted to delineate the various groundwater potential zones based on hydrogeomorphological investigations Morphometric analysis is the measurement and mathematical analysis of the configuration of the earth&#39;s surface, shape and dimension of its landforms (Clarke, 1966). This analysis can be achieved through measurement of linear, aerial and relief aspects of the basin and slope contribution (Nag and Chakraborty, 2003). The present study area of Bor River basin is a tributary of Pedi River lying in the Amravati district. For the Morphometric analysis Geographic information system techniques has been used and Strahler (1964) stream order method used for stream ordering. The drainage density (D) of study area is 1.9674 km indicating low to moderate drainage density. In this study an attempt has been made to understand the morpho-tectonic analysis of the Bor river basin by utilizing the remote sen...

There has been substantial public debate over the last 20 years among politicians, citizens, environmentalists, geographers, meteorologists and other scientists from a variety of fields regarding the topic of Global Climate Change (GCC).  Rising concern about serious storm damage resulting from both tropical and extratropical storms has also fueled this world-wide debate.  A maritime researcher at the Virginia Institute of Marine Science, John Boon, discusses in Sea Level Rise and Coastal Infrastructure, Prediction Risks and Solutions, the impact of major storms on communities and infrastructure along the Mid-Atlantic coastline of U.S. East Coast (USEC).  Boon postulates that a consequence of Sea Level Rise (SLR) is that extratropical storms will begin to create significant flooding issues in the future. The lower Chesapeake Bay region, with land subsidence rates among the highest on the USEC, now has relative SLR rates in the 4 to 6 mm/year range, making it particularly sensitive to increased flooding with time. The study suggests it is absolutely critical that real-time data and enhanced metrics are needed to study the severity of this effect.

Our understanding of bottom-currents and associated oceanographic processes (e.g., overflows, barotropic tidal currents) including intermittent processes (e.g., vertical eddies, deep sea storms, horizontal vortices, internal waves and tsunamis) is rapidly evolving. Many deep-water processes remain poorly understood due to limited direct observations, but can generate significant depositional and erosional features on both short and long term time scales. This paper represents a review work, which describes for the first time these oceanographic processes and examines their potential role in the sedimentary features along the Iberian continental margins. This review explores the implications of the studied processes, given their secondary role relative to other factors such as mass-transport and turbiditic processes, and highlights three major results: a) contourite depositional and erosional features are ubiquitous along the margins, indicating that bottom currents and associated oceanographic processes control the physiography and sedimentation; b) the position of interfaces between major water masses and their vertical and spatial variation in time specifically appears to exert primary control in determining major morphologic changes along the slope gradient, including the contourite terraces development; and c) contourites deposits exhibit greater variation than the established facies model suggests. Therefore, a consistent facies model however faces substantial challenges in terms of the wide range of oceanographic processes that can influence in their development. An integrated interpretation of these oceanographic processes requires an understanding of contourites, seafloor features, their spatial and temporal evolution, and the near-bottom flows that form them. This approach will synthesize oceanographic data, seafloor morphology, sediments and seismic images to improve our knowledge of permanent and intermittent processes around Iberia, and evaluate

This work was realized in the coastal plain of Itaguai city, Rio de Janeiro state, aiming to analyze the subsurface clay collected from sandy ridges with the aim of characterizin g the paleoenvironmental evolution of this area. For that purpose, we drilled several boreholes followed by particle size and mineralogical X-ray diffraction analysis. In the analysed samples, kaolinite, illite, smectite and traces of goethite were identified in descending order of abundance. This mineralogical association is typical for warm intertropical, lacustrine and/or river environment. Consequently, we can purpose a fluvial-deltaic paleoenvironment for this area including the presence of an ancient restricted intradune lake.

This work was realized in the coastal plain of Itaguai city, Rio de Janeiro state, aiming to analyze the subsurface clay collected from sandy ridges with the aim of characterizin g the paleoenvironmental evolution of this area. For that purpose, we drilled several boreholes followed by particle size and mineralogical X-ray diffraction analysis. In the analysed samples, kaolinite, illite, smectite and traces of goethite were identified in descending order of abundance. This mineralogical association is typical for warm intertropical, lacustrine and/or river environment. Consequently, we can purpose a fluvial-deltaic paleoenvironment for this area including the presence of an ancient restricted intradune lake.

The trace elements (Ti, V, Cr, Mn, Ni, Cu, Zn, Mo, Pb) accumulation in modern bottom sediments of Belarusian reservoirs and rivers in the places of higher aquatic vegetation growing has been analyzed on monitoring data for the period of 2000 –2015 years. The distribution of the studied elements majority (Ti, V, Cr, Mn, Ni, Cu, Pb) in the reservoir bottom sediments obeys lognormal law distribution. The lakes with the anomalous concentrations of Ni, V, Cu, Cr, Pb in the bottom sediments have been identified. The spatial distribution of Ti, Cr, Mn, Cu in the reservoirs bottom sediments is random. For Pb a cluster of high values in the North of Belarus (Osveiskoe, Bredno, Beloe and Mokhovoe lakes) has been revealed. The mean concentrations of V, Cr, Mn, Ni in the rivers bottom sediments are higher than in the reservoirs bottom sediments. The elements associations in the bottom sediments of reservoir and rivers have been identified by using principal component analysis. The elements of t...

Iz,`adak: ()vaj rad razmatra obalno podrue i podmorje Rx'jekog zaljeva. Recentni reljef u podruju Rijekog zaljeva posljedica je tektonskih pokreta, promjena klime i morske razine tijekom be geolokc proosti, a takoder i egzogenetskih procesa. Klimatske promjene i glacioeustatike oscilacije mora tijekom posljednjih 700 000 godina sruumo su utjecale na promjene reljefa, pa su ueni tragovi starijih morfogenetskih etapa. Na dnu Rijekog zaljeva vjerojatno su bila izolirana jezera na vrhuncu virmske regresije. Kki izvori bili su na kotama znatno m od danagnjih. Sadaji poloj i oblik obala koje okuju Rijeki zaljev, posljedica su ponajprije potapanja kopna poradi holocenske transgresx'je. Rijetki klifovi i uske marinske (erase jasni su pokazatelji mladosti obalnog reljefa. KIjue Morfogeneza, razina mom, klimatske promjene, kvartar, Rijeki zaljev, Jadransko more. MORPHOLOGICAL EVOLUTION OF THE RIIEKA BAY: TH E INFLUENCE OF THE CLIMATIC AND GLACIOEUSTATIC CHANGES Abs(met: This paper analyses the coastal and the submarine zones of the Rijeka Bay, part of the Kvarner Channel area in the North Adriatic. The recent relief of the Rijeka Bay area is the result of tectonic movements, climatic and sea level changes, as well as exogenetic processes, occuring during the early geological time. The climatic changes and glacioeustatic sea level oscilations for the past 700 OOfl years have strongly transformed the relief, and have also destroyed the remains of the older morphogenetic phases. Isolated lakes on the bottom of the Rijeka Bay possibly existed at the peak of Wuerm regression. The riverbeds are deeply cut into the bedrock and karst springs were at much lower levels than today. The recent position of the coastal line is a result of the flooding of ancient land areas due to Holocene transgression. The clear indicators of the initial and youthful stage of the coastal relief are the rare cliffs and narrow marine terraces.

Iz,`adak: ()vaj rad razmatra obalno podrue i podmorje Rx'jekog zaljeva. Recentni reljef u podruju Rijekog zaljeva posljedica je tektonskih pokreta, promjena klime i morske razine tijekom be geolokc proosti, a takoder i egzogenetskih procesa. Klimatske promjene i glacioeustatike oscilacije mora tijekom posljednjih 700 000 godina sruumo su utjecale na promjene reljefa, pa su ueni tragovi starijih morfogenetskih etapa. Na dnu Rijekog zaljeva vjerojatno su bila izolirana jezera na vrhuncu virmske regresije. Kki izvori bili su na kotama znatno m od danagnjih. Sadaji poloj i oblik obala koje okuju Rijeki zaljev, posljedica su ponajprije potapanja kopna poradi holocenske transgresx'je. Rijetki klifovi i uske marinske (erase jasni su pokazatelji mladosti obalnog reljefa. KIjue Morfogeneza, razina mom, klimatske promjene, kvartar, Rijeki zaljev, Jadransko more. MORPHOLOGICAL EVOLUTION OF THE RIIEKA BAY: TH E INFLUENCE OF THE CLIMATIC AND GLACIOEUSTATIC CHANGES Abs(met: This paper analyses the coastal and the submarine zones of the Rijeka Bay, part of the Kvarner Channel area in the North Adriatic. The recent relief of the Rijeka Bay area is the result of tectonic movements, climatic and sea level changes, as well as exogenetic processes, occuring during the early geological time. The climatic changes and glacioeustatic sea level oscilations for the past 700 OOfl years have strongly transformed the relief, and have also destroyed the remains of the older morphogenetic phases. Isolated lakes on the bottom of the Rijeka Bay possibly existed at the peak of Wuerm regression. The riverbeds are deeply cut into the bedrock and karst springs were at much lower levels than today. The recent position of the coastal line is a result of the flooding of ancient land areas due to Holocene transgression. The clear indicators of the initial and youthful stage of the coastal relief are the rare cliffs and narrow marine terraces.

The Southwestern Atlantic margin is characterized by several canyon systems incised on a huge Contourite Depositional System associated with the interaction of strong Antarctic water masses with the seafloor. So far, however, only one mega slide canyon (Cabo Polonio) has been described recently in the Uruguayan continental slope. In this work, sedimentary processes dominating the head of this mega slide canyon are described and interpreted based on the analysis of the composition (texture and fossils) and distribution of gravel widespread along its head and thalweg, and integrated with acoustic (multibeam and seismic) and hydrological data. Results suggest that the evolution of the head of the canyon presents retrogressive erosion related to debris and turbidity flows. This erosion is ongoing and/or has been active during the recent past and contourite deposits are involved in headwall erosion. The pathway of gravel along the canyon and the thalweg was reconstructed. The strong flow...

Resumo ? Foram estudadas as características hidrodinâmicas do canal de Piaçaguera e da plataforma continental ao largo da baía de Santos, como suporte a obras de dragagem no canal e visando a delimitação de áreas de deposição dos materiais dragados. Foram realizadas observações na forma de séries temporais de: 1) correntes e propriedades físicas no canal, 2) nível do mar e meteorologia de superfície na linha da costa e 3) perfis verticais de correntes em duas estações ao largo. Complementando as análises das medições, as características hidrodinâmicas das regiões de plataforma e estuarina foram simuladas através de modelos numéricos hidrodinâmicos tri-dimensionais.

A implantacao de industrias e a elevada densidade populacional promovem diversas mudancas no ambiente maritimo, em particular, nas regioes litorâneas. Levando-se em conta a o grande numero de industrias no entorno da Baia de Sepetiba e da distribuicao logistica das mesmas nesta regiao, buscou-se estudar a contaminacao de seu sedimento superficial por mercurio. Para tal foram coletadas amostras ao longo de toda a extensao da baia, tendo sido determinada a concentracao de mercurio atraves da tecnica de espectroscopia de absorcao atomica por vapor frio. Verificou-se elevadas concentracoes do metal no interior da baia, sobretudo em sua regiao nordeste, onde tambem foram encontrados os maiores niveis de sulfetos. Desta forma, a partir dos dados coletados pode-se compreender que, apesar dos elevados niveis de mercurio encontrados, mesmo nao deve estar numa forma biodisponivel por se encontrar precipitado com sulfeto em uma forma imobilizada

The study was conducted to determine the socioeconomic condition of the fisher's community over an area of 4 kilometers of Meghna River at Ashuganj upazila under Brahmanbaria district from January to April 2009. In this study, 10 fishers were randomly selected from each kilometer, thus the total sample size was 40. Studies on socioeconomic conditions of Meghna river fishermen were carried out in terms of religious status, age structure, educational status, health facilities, and drinking water facilities, housing condition, sanitary facilities and annual income, catch and species composition. It was found that 90% of the fishermen were Hindus and 10% were Muslim in study area 1 and 65% of the fishermen were Muslim and 35% were Hindus in study area 2. About 2.5% had literacy up to secondary level and 45% can sign only. About 75% and 80% of the fishermen had katcha house while 7.5% and 2.5% fishermen had half-building house in study area 1 and study area 2 respectively. Sanitary conditions of the fishermen were very poor and most of the toilets (50%) were katcha. About 15% of the fishermen have their own tube well and 50% of the fishermen used katcha toilet in study area-1 and in study area-2 47.5% of the fishermen used katcha toilet, 42.5% used semi pucca toilet and the rest of them used pucca toilet. Family size of the fishermen consisted of 2-11 persons. Among those, small family consisted of 2-4 members and large family consisted above 7 members. The highest income of fishermen from Tk 1,00,000-2,00,000/year was 52.5% and the lowest income of fishermen from Tk 25,000-50,000/year was 5%. Besides, various recommendations and necessary measures have been suggested to improve livelihood of fishers' community of the Meghna river.

Knowledge of bedload transport is of primary importance in a number of aspects in watershed management, including fluvial geomorphology and ecology, stability of engineered structures and navigation condition. Despite the fundamental importance of bedload measurement, the amount of variables involved in the bedload transport mechanics, as well the complexity of the interactions among the physical processes, makes it difficult to establish a fully satisfactory criteria to determine the solid transport, thus there is not an accepted universal method. With recent advances, new methods have been proposed for measuring the bedload transport. Therewith, the aim of this study was to evaluate the suitability of methodologies for bedload measurement on a reach of the Doce River, ES. For this were used traditional direct sampling method, with Helley Smith's sampler; formulas proposed by Einstein & Brown (1950), Engelund & Hansen (1967), Ackers & White (1973), Yang (1973) e Van Rijn (1984); bedform movement methods, considering velocity of bedform displacement and the difference between bed surfaces; and bedload velocity using an ADCP. Results indicated an unstable flow, with a bed composed primarily of fine and medium-sized sand, and bedforms in transition. Bedload values obtained by different methods showed variation of different orders of magnitude, and the highest estimates were provided by the equation of Yang (1973). The application of the bedform movement methods has been complicated by the bed condition at the site. However, the bedload measured from the velocity of bedform displacement has been quite consistent with the hydraulic conditions. The equations of Engelund & Hansen (1967) and Van Rijn (1984), and the bedload velocity method showed excellent performance, and the latter being a very promising alternative for the measurement of the bedload. To confirm the suitability of these methods in the Doce river (ES) is suggested to be carried out more measurements, in a uniform stretch, primarily using the bedload velocity and the bedform displacement methods.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em Geografia.O presente trabalho teve como objetivo comparar a distribuição de descritores biossedimentológicos no sedimento superficial de duas fazendas de cultivo de moluscos marinhos localizadas na Baía Sul, Ilha de Santa Catarina (SC/Brasil). Procurou-se avaliar a influência das condições hidrodinâmicas sobre a distribuição destes descritores nas áreas do cultivo e seu entorno, bem como, analisar algumas respostas do ambiente na assimilação e acumulação dos biodetritos liberados pelos cultivos. A metodologia empregada compreendeu técnicas amostrais e analíticas ajustadas às diferentes escalas de trabalho. Foram utilizados três grupos de descritores oceanográficos: hidrodinâmicos e batimétricos (correntes e geomorfologia de fundo); sedimentológicos (granulometria e constituintes orgânicos) e ecológicos (composição e distribuição de espécies de foramin...

Kinetic study of phosphor and nitrogen compounds through resuspension sediment has been carried out to determine their time release from sediment to the water column. This laboratory study was performed by stirring the sediment within the seawater at an equal current speed of 1 m/sec. Nutrients were observed at several intervals of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 40 minutes by sampling 25 ml water mixture with 3 time as replicates. The increase of nutrient occurred significantly during 5 minutes. Their average contribution of nutrient per gram sediment reached 1.827 μg phosphate, 0.292 mg ammonia, 0.276 mg ammonium, 1.776 μg nitrite and 9.059 μg nitrate. The extent of nutrient increase was probably depended upon characteristic of sediment (composition of nutrient availability) and resuspension speed.

Kinetic study of phosphor and nitrogen compounds through resuspension sediment has been carried out to determine their time release from sediment to the water column. This laboratory study was performed by stirring the sediment within the seawater at an equal current speed of 1 m/sec. Nutrients were observed at several intervals of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 40 minutes by sampling 25 ml water mixture with 3 time as replicates. The increase of nutrient occurred significantly during 5 minutes. Their average contribution of nutrient per gram sediment reached 1.827 μg phosphate, 0.292 mg ammonia, 0.276 mg ammonium, 1.776 μg nitrite and 9.059 μg nitrate. The extent of nutrient increase was probably depended upon characteristic of sediment (composition of nutrient availability) and resuspension speed.

O sistema da Corrente do Brasil (CB) é caracterizado pelo meandramento e a geração de vórtices associados à corrente. E, constitui o principal sistema de correntes ao largo da região sudeste brasi- leira, região de enorme importância econômica, biológica e geopolítica para o Brasil. A dinâmica da corrente do Brasil é inuenciada principalmente pelo local de formação, a batimetria, e a instabilidade baroclínica e barotrópica. O cálculo do transporte volumétrico da Corrente do Brasil (CB) e da Co- rrente de Contorno Intermediária (CCI) em 23 ° S é realizado neste trabalho usando dados de reanálises do modelo HYCOM-NCODA. A série histórica de vazão foi analisada usando a estatística básica e a transformada de wavelet. Os resultados do espectro de wavelet mostram um ciclo anual bem marcado na CB e na CCI. Assim como padrões de variação diferentes entre a CB e a CCI, sendo encontrado nesta última maior variabilidade no espectro.

The research work deals with the hydrogeological condition of Cox’s Bazar area in Bangladesh. Most of the area is covered by northern part of Inani anticline. The structure is elongated, broad crest, steep flank, box-like and asymmetrical anticline. It is very hard to measure aquifer geometry of a complex geological area like Inani anticline. Hydrogeologically the study area broadly divided into two zones; Zone-1: Alluvium and Zone-2: Complex geology. From the analysis of the individual log and subsurface hydrostratigraphic sections, eight confined aquifer (Aquifer A, Aquifer B, Aquifer C, Aquifer D, Aquifer E, Aquifer F, Aquifer G and Aquifer H) and one unconfined aquifer (Aquifer O) observed in the Complex geology zone and the Alluvium zone in the study area respectively. The water tables in the confined aquifers are lies in high depth but in case of unconfined aquifer the water table lies near to the surface. From the structural geological condition and position of the aquifers, ...

Other personnel associated with the FIT made substantial contributions to the data collection and analysis effort. Mr. Douglas Chapman designed and built the instrument packages. Mr. Richard Gurlek captained the research vessel during instrument deployment and retrieval. Mr. Clement R. Surak assisted in analysis and quality control of the data. Mr. Kenneth Connell and Ms. Michelle Peters provided logistical support and coordination assistance in the field effort. This study was performed under the general supervision of Dr.

The illaenid trilobite Vysocania is widely represented in the Upper Ordovician of the Czech Republic, Portugal and Spain, and is one of the most characteristic taxa in the high-latitude peri-Gondwana palaeobiogeographical region to which it is endemic. Three species of the genus that were formerly assigned to Stenopareia and Zetillaenus, from the Czech Republic and Spain respectively, are herein revised, and a new species is described from the Czech Republic. The genus Octillaenus, of which a new species is described from the Upper Ordovician of Morocco, is considered to have arisen from Vysocania through paedomorphic (neotenic) processes. The relationships between Vysocania, Octillaenus, Stenopareia and Zetillaenus are reviewed and the criteria used in the definition of these taxa discussed. Species assigned to Vysocania are V. vaneki (type-species), V. iberica, V. moraveci sp. nov. and V. panderi; species assigned to Octillaenus are O. hisingeri (type-species) and O. marocanus sp. nov. Vysocania appears for the first time in the lower Berounian (Sandbian) and has its last undoubted record in the upper Berounian (upper Katian); Octillaenus is presently restricted to the Kralodvorian (upper Katian). • Key words: Stenopareia, Zetillaenus, Illaenidae, high-latitude peri-Gondwana, Dalmanitoidean Realm.

Penelitian ini dilakukan untuk mengetahui karakteristik dan potensi perairan Teluk Buyat dan Teluk Ratatotok guna mendukung potensi sumberdaya hayati ekosistem laut dan pesisir, khususnya ekosistem lamun. Penelitian dilakukan pada Juni 2013 pada 6 stasiun di Teluk Buyat dan 4 stasiun di Teluk Ratatotok. Parameter yang diukur in situ dengan menggunakan alat water quality meter adalah pH, salinitas dan suhu. Parameter nitrat, fosfat dan klorofil-a dianalisis dengan menggunakan metode APHA. Data tutupan lamun diperoleh dengan metode transek kuadrat sesuai Seagrass Watch Method. Hasil pengamatan dipetakan secara spasial menggunakan Ocean Data View. Analisis hubungan antara parameter perairan dan tutupan lamun dilakukan dengan menggunakan Principal Component Analisis. Hasil penelitian menunjukkan bahwa suhu, salinitas dan klorofil-a pada perairan berperan penting pada tutupan lamun dan secara umum kondisi perairan Teluk Buyat dan Teluk Ratatotok masih dalam kategori baik dan subur serta layak untuk kehidupan biota laut, khususnya ekosistem lamun.

Την 3η Μαρτίου 2020 και ώρα Ελλάδας 12:16 σημειώθηκε στη Θεσσαλία ισχυρή σεισμική δόνηση μεγέθους Μw6.3. Σύμφωνα με την ανακοίνωση του Εθνικού Σεισμογραφικού Δικτύου επρόκειτο για επιφανειακό (h~8 km) σεισμό με το επίκεντρο του να εντοπίζεται στη περιοχή το Τυρνάβου σε απόσταση περίπου 22 km ΔΒΔ από τη Λάρισα και 8 km από τον Τύρναβο. Ενδεικτικά οι γεωγραφικές συντεταγμένες του επικέντρου όπως δίνονται από την ιστοσελίδα του Σεισμολογικού Σταθμού του ΑΠΘ (http:// http://geophysics.geo.auth.gr/ss) είναι 39.7320Β 22.2180A. Στις 13:45 έγινε ένας μετασεισμός Μw5.1. Την 4η Μαρτίου στις 20:31 έγινε ένας ακόμη ισχυρός σεισμός με μέγεθος Mw6.1. O ισχυρότερος σεισμός (μέχρι 16.03.2021) έγινε την 12η Μαρτίου με μέγεθος Mw5.6. Ο σεισμός αυτός έγινε στο βορειοδυτικό άκρο της ζώνης διάρρηξης.

The Southwestern Atlantic margin is characterized by several canyon systems incised on a huge Contourite Depositional System associated with the interaction of strong Antarctic water masses with the seafloor. So far, however, only one mega slide canyon (Cabo Polonio) has been described recently in the Uruguayan continental slope. In this work, sedimentary processes dominating the head of this mega slide canyon are described and interpreted based on the analysis of the composition (texture and fossils) and distribution of gravel widespread along its head and thalweg, and integrated with acoustic (multibeam and seismic) and hydrological data. Results suggest that the evolution of the head of the canyon presents retrogressive erosion related to debris and turbidity flows. This erosion is ongoing and/or has been active during the recent past and contourite deposits are involved in headwall erosion. The pathway of gravel along the canyon and the thalweg was reconstructed. The strong flow...

Pelabuhan Lembar merupakan salah satu pintu utama menuju pulau Lombok yang terletak di Teluk Lembar. Sungai Bagong yang bermuara di teluk ini diduga membawa material sedimen sehingga menyebabkan potensi pendangkalan pada alur pelayaran Pelabuhan Lembar. Erosi yang terjadi pada pantai Cemara juga berpengaruh terhadap pendangkalan Teluk lembar. Arus diukur menggunakan Current Meter pada kedalaman 10 m dan pengambilan contoh sedimen permukaan dasar perairan menggunakan Sedimen Grab, sedangkan data sekunder berupa peta bathimetri dan peramalan pasang surut Teluk Lembar. Sedimen dasar yang mendominasi daerah penelitian adalah jenis pasir dan pasir lanauan. Kecepatan arus total maksimum dalam pengukuran adalah 0.1469 m/s dengan arah dominan 159 o dan kecepatan arus total minimum 0.0193 m/s dengan arah dominan 338 o. Jenis arus yang mendominasi di perairan Teluk Lembar adalah arus pasang surut dengan persentase dominasi arus pasang surut sebesar 83.74% dan arus residu (non pasang surut) sebesar 16.26%. Simulasi pergerakan arah arus pada 4 kondisi pasang surut menggunakan software SMS 8.1. Pengolahan pasang surut dengan software World Tide perairan Lembar diperoleh HHWL (Highest High Water Level) sebesar 210.1 cm, LLWL (Lowest Lower Water Level) sebesar 10 cm dan MSL (Mean Sea Level) sebesar 110.1 cm sedangkan bilangan Formzahl (F) adalah 1.37 yaitu tergolong tipe campuran condong ke harian ganda. Potensi pendangkalan terjadi di sekitar Tg. Cemara dan Muara Sungai Bagong yang merupakan alur pelayaran Pelabuhan Lembar dilihat dari persebaran sedimen dasar jenis pasir dan adanya gosong pasir di depan muara Kali Bagong. Berkaitan dengan hal tersebut, maka dilakukan penelitian tentang arus dan sedimen dasar di perairan tersebut.

O presente trabalho analisa a variabilidade do nível da água na costa de Fortaleza, CE, através de registros do nível da água e de ondas. O objetivo é avaliar estatisticamente as ocorrências de níveis positivos, acima do nível de referência de baixa mar de sizígia de solstício, e os efeitos de ondas que produzem anomalias negativas. As implicações dos resultados são relevantes para as operações portuárias locais. Dados de nível de água foram obtidos a partir do marégrafo do Instituto Brasileiro de Geografia e Estatística (IBGE) instalado no píer do Porto do Mucuripe. Dados de altura máxima de onda foram obtidos a partir de observações realizadas ao largo do Porto do Pecém e disponibilizados pelo Instituto Nacional de Pesquisas Hidroviárias (INPH). Funções de densidade de probabilidade (FDP) foram determinadas para ondas e nível da água. A partir da FDP de nível de água foi calculado o número de horas por ano que o nível está acima do nível zero. Foi realizada a convolução das FDPs para obter a FDP conjunta, empregando a amplitude de onda negativa. Foi observado que níveis abaixo do nível zero ocorrem em menos de 0,5% do tempo, o que para um ano representa cerca de 15 dias.

Numerous bottom current-controlled depositional and erosional features, which together form Contourite Depositional Systems (CDS), have been recognized in deep-water settings over the past decade. Most of these systems are described based on two-dimensional (2D) seismic data, whereas only a few CDS have been characterised from high-resolution 3D data. Here we document a newly identified CDS that formed during the Paleocene within the Morondava Basin, offshore west Madagascar, through analysis of a depth-migrated 3D seismic survey, enhanced by the implementation of seismic attributes. Three seismic units (SU) mark the main evolutionary stages of the CDS: (a) the onset (SU1), (b) drift growth (SU2), and (c) burial (SU3) stages. The growth stage documents lateral upslope migration of a mounded drift and its associated moat. The increasing, long-term influence of bottom currents along the foot of the slope occurred simultaneously with plate tectonic, climatic and oceanographic changes. ...

An assessment of the impact of sea level rise on the city of Port Said, Egypt has been carried out using remote sensing and GIS techniques. Bruun&#39;s is used to estimate horizontal retreat, due to three scenarios of sea level rise, taking into account local subsidence rates. Overlaying horizontal retreat on land use obtained by remote sensing enabled us to

Observations of long-term change in the shoreline and bathymetry on the inner continental shelf off the northern Nile delta are based on comparison of two bathymetric maps of closelyspaced soundings from 1919/22 and 1986. The changes are depicted after analyses of 40 bathymetric profiles in water depths as great as 30 m and extending about 30 km from the shore. Comparison among these profiles in terms of changes in water depth, shifting in bottom contours and volumetric changes in bottom sediments, identifies areas of erosion (Abu QuiT Bay, Rosetta promontory, east of Burullus, and Damietta promontory) and accretion (Abu Khashaba coast, West Burullus inlet, Gamasa and the Damietta spit). These changes are generally due to longterm sediment movement in which most of the accreted sands come from eroded promontory tips 8S well as from offshore sources. Statistical correlation analysis indicates that areas of potential erosion and accretion are not related to sediment texture, slope gradient and water depth.

An integrated study of geological and geophysical data of the Río de la Plata region and its relation to the evolution of the Atlantic passive margin is herein described. This characterization is based on the available geological and geophysical information and on the correlation of the southern end of the best-known Santa Lucía Basin in Uruguay to the Salado Basin in Argentina, and their connection through the Quilmes Trough. Furthermore, a new Meso-Cenozoic depocenter is characterized and identified as Recalada Trough, subparallely aligned to the Quilmes Trough and separated from it by the Magdalena-Montevideo High. Both sedimentary fillings present ENE-WSW trending main axes and reach an average thickness of almost 2,000 m. This suggests an evolution from a triple junction where interconnected extensional arms developed, which have had common Mesozoic tectosedimentary histories related to the early opening of the Atlantic Ocean. Based on the geophysical and geological evidence, the previously accepted existence in the Río de la Plata of a first-order structural feature along the international border between Argentina and Uruguay, associated to an ENE-WSW trending tectonic high, identified as Martín García, is unjustified. The tectonic evolution of the Atlantic margin in front of the Río de la Plata estuary is the consequence of a long deformation history starting in the Precambrian up to recent times. Each Precambrian, Paleozoic, Mesozoic and Cenozoic tectonic scenario adds different weak trends on the continental crust, which control the evolution of the sedimentary depocenters. The presence of these tectosedimentary records influence the bathymetric control of the Río de la Plata and the dynamics of the recent estuarine deposits. The Meso-Cenozoic sedimentary infill is estimated to comprise considerable ranges of sandstones and conglomerates associated with faulted blocks of the crystalline basement, with expected petrophysical conditions oscillating in the order of 12% to 15% of effective porosity and with expected traps of the stratigraphic and combined (closing against faulting) type, and overlapped by fine sediments with excellent quality as seals. The economic significance of these sedimentary volumes lies in their yet unexplored potential as natural fluid reservoirs (hydrocarbons and groundwater), of great importance due to their strategic position near the large urban areas of Buenos Aires and Montevideo.

Από το 2009 το διαστημικό τηλεσκόπιο Kepler καταγράφει τις μικρές ελαττώσεις (εκλείψεις) στο φως μακρινών αστέρων που οφείλονται στη διάβαση (transit) πλανητών από μπροστά τους. Σκοπός μας είναι να εντοπίσουμε πλανήτες σε τροχιά γύρω από μακρινά άστρα από τα δεδομένα της αποστολής Kepler, χρησιμοποιώντας τη Μέθοδο των Διαβάσεων με τη βοήθεια δύο προγραμμάτων που έχει γράψει η ομάδα μας σε γλώσσα C. Εφόσον εντοπιστούν και επιβεβαιωθούν οι διαβάσεις, προχωρούμε στην ανάλυση των χαρακτηριστικών του πλανήτη: Ακτίνα, κλίση, απόσταση από το αστέρι, και κυρίως αν βρίσκεται στη λεγόμενη «κατοικήσιμη ζώνη» πράγμα που θα κάνει δυνατή τη διατήρηση ζωής.Λόγω του πολύ μικρού μεγέθους των πλανητών σε σχέση με το αστέρι τους, ο εντοπισμός αυτός είναι εξαιρετικά δύσκολος. Παρόλα αυτά έχουμε ήδη εντοπίσει έναν τέτοιο εξωπλανήτη σε τροχιά γύρω από τον αστέρα KIC 1432789 τα χαρακτηριστικά του οποίου ανέλυσε η ομάδα μας για πρώτη φορά.

A identificação de seções da costa sensíveis ao aumento do nível do mar é necessária para uma gestão mais eficaz da zona costeira, a fim de aumentar a resiliência e ajudar a reduzir os impactos. Porém, a diversidade de sistemas costeiros e as diferenças regionais de aumento relativo do nível do mar fazem com que a resposta para os fenômenos de erosão e inundação costeira não sejam uniformes no globo. Por isto, a avaliação da sensibilidade costeira assume o ponto de partida para a avaliação da vulnerabilidade. No entanto, desafios metodológicos são decorrentes desta difícil tarefa de compreender e avaliar a dinâmica dos ecossistemas costeiros. Além disso, inconsistências conceituais em torno do termo vulnerabilidade podem gerar incompreensões metodológicas e o emprego distraído de certas variáveis pode comprometer os índices de sensibilidade costeira. Este artigo se propõe a contribuir com uma base conceitual e metodológica destinada aos pesquisadores que irão iniciar na jornada de m...

Um método de medição óptica de ondas superficiais de gravidade é desenvolvido e aplicado para ondas regulares bimodais. O método consiste na análise dos padrões espaciais e temporais do brilho no plano da imagem ao longo de uma sequência de frames. As medições são configuradas objetivando simplificar sua aplicação operacional. Para tanto emprega-se apenas um ponto de vista da cena visualizada, o que representa uma considerável vantagem em detrimento das configurações estereoscópicas usualmente apresentadas na literatura. Os resultados demonstram que é possível identificar o período e a direção de propagação de cada uma das componentes de onda.

A zona costeira do Rio de Janeiro constitui um sistema geoecológico frágil e vulnerável, sendo amplamente ocupada pelo homem, pois possui condições favoráveis em seu entorno para assentamento. É uma área particularmente sensível, onde as praias estão sob pressão de atividades e intervenções antrópicas. Assim, a urbanização inadequada pode levar a uma série de impactos, causando degradação ambiental dos ecossistemas costeiros. Atualmente, o município de Mangaratiba tem sido alvo de intensa especulação imobiliária, como objeto de disputa entre a expansão urbano-industrial-portuário e as atividades de pesca artesanal e turismo, historicamente associadas ao patrimônio natural. Neste contexto, o presente trabalho testou uma rotina metodológica que analisa dados de sensoriamento remoto ao longo de um período de 30 anos, considerando os instantes de 1984-uma década após a construção da Rodovia Rio-Santos (BR-101) e dois anos após a construção do Porto de Sepetiba (atual Porto de Itaguaí), no ano de 1982-e prorrogação para a inauguração do Arco Metropolitano do Rio de Janeiro, em 2014, como base para a construção da Matriz de Transição de Markov para o ano de 2034 Os resultados incluem simulações e estabelecimentos dos cenários de desenvolvimento, bem como um diagnóstico da expansão urbana no município, a espacialização dessas áreas.

Continuous records of temperature and sa1inity wer.e obtained on the surface waters as function of the horizontal distances around Ilha Grande region, on June 21, 1975; an outflow of less sa1ine (S-33.10 0/00) and slight1y warmer water was detected throughout the region between Ponta de Castelhanos and Ponta Grossa da Marambãia and a visible manifestation of a saline front was observed in the interaction of this outflow with the coas tal and more saline water (S ~ 35.4 to 35.6 0/00). The recorded sa1inity va1ues in the east region of Ilha Grande, suggest that the source of 1ess saline water is the runoff in the Baía de Sepetiba. * Grants were awarded to the authors by Fundação de Amparo a Pesquisa do Estado de são Paulo (FAPESP).

O presente trabalho traz informações sobre coleta de dados de correntes realizadas na Baía de Paranaguá, PR, Brasil, utilizando correntômetros eletromagnéticos (S4) e de efeito Doppler (ADCP e ADP), assim como do estudo dos sedimentos em suspensão observados na coluna d'água. A comparação dos resultados das correntes observadas, por todos os instrumentos, mostrou que estes são muito equivalentes neste tipo de observação. Por outro lado, a vazão líquida obtida com base nos dados dos correntômetros acústicos resultaram completamente compatíveis com o prisma de maré (vazão de maré). Os dados de vazão assim obtidos permitiram a elaboração do equivalente estuarino das curvas de vazão, das quais, conhecido o nível, é possível calcular a vazão numa dada seção. As análises de material particulado em suspensão foram utilizadas, também, para tentar correlacionar o MPS com a intensidade do eco do ADCP, observando-se que é possível utilizar esta intensidade para estimativas do MPS. Desde o ponto de vista dinâmico, a principal característica observada na circulação da Baía de Paranaguá refere-se à heterogeneidade lateral das seções, onde apareceram claramente sistemas de circulação residual, em que as áreas da seção são usadas principalmente pelas correntes de enchente, sendo outras para as correntes de vazante. Esta circulação preferencial pode explicar as diferentes condições laterais nos canais, onde na área de preponderância das correntes de enchente observam-se condições biológicas e sedimentológicas com características mais "marinhas", sendo que nas áreas de vazante, ocorre o contrário, com fauna e sedimentos menos marinhos e mais continentais ou interiores.

O presente trabalho traz informações sobre coleta de dados de correntes realizadas na Baía de Paranaguá, PR, Brasil, utilizando correntômetros eletromagnéticos (S4) e de efeito Doppler (ADCP e ADP), assim como do estudo dos sedimentos em suspensão observados na coluna d'água. A comparação dos resultados das correntes observadas, por todos os instrumentos, mostrou que estes são muito equivalentes neste tipo de observação. Por outro lado, a vazão líquida obtida com base nos dados dos correntômetros acústicos resultaram completamente compatíveis com o prisma de maré (vazão de maré). Os dados de vazão assim obtidos permitiram a elaboração do equivalente estuarino das curvas de vazão, das quais, conhecido o nível, é possível calcular a vazão numa dada seção. As análises de material particulado em suspensão foram utilizadas, também, para tentar correlacionar o MPS com a intensidade do eco do ADCP, observando-se que é possível utilizar esta intensidade para estimativas do MPS. Desde o ponto de vista dinâmico, a principal característica observada na circulação da Baía de Paranaguá refere-se à heterogeneidade lateral das seções, onde apareceram claramente sistemas de circulação residual, em que as áreas da seção são usadas principalmente pelas correntes de enchente, sendo outras para as correntes de vazante. Esta circulação preferencial pode explicar as diferentes condições laterais nos canais, onde na área de preponderância das correntes de enchente observam-se condições biológicas e sedimentológicas com características mais "marinhas", sendo que nas áreas de vazante, ocorre o contrário, com fauna e sedimentos menos marinhos e mais continentais ou interiores.