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We report on the source of pumice found on beaches of Tierra del Fuego (Argentina) and the South Shetland Islands (Antarctica), north and south of the Drake Passage. Petrological studies, chemical analyses and experiments on this pumice indicate it is most likely from a 1962 submarine eruption in the South Sandwich Islands. Previous work stated that clockwise marine currents carried such pumice as far as Tasmania. Our findings show that the currents continued to transport the pumice to Drake Passage, nearly completing a circuit around Antarctica, and up to southern Argentina showing that this material can follow complex pathways for more than 20 000 km.

This paper describes the rationale and the engineering approach adopted for the development of technology for converting the kinetic energy in marine currents for large-scale electricity generation. Although the basic principles involved are relatively straightforward and well understood, being similar to those of a wind turbine, a practical and cost-effective large-scale system designed to extract the kinetic energy of flowing water has yet to be developed. This paper describes the research and development being undertaken through an industrial consortium with the aim of achieving this goal for the first time, i.e. to achieve the world's first commercially viable systems for delivering power from marine currents.

Application of marine currents for electricity generation could offer a distinct advantage over other renewable energy sources due to the regular and predictable nature of this resource. This paper details the application of AHP (Analytical Hierarchy Process) as a possible tool to help decision makers comprehend better the environment and the impacts of the marine current turbines. Towards the usage of a tridimensional model (TELEMAC3D) the best spots for generating energy for the currents were found and then applied into the AHP. Several database were compared to minimise decision deviation. The results enhance the viability of the northern region of the Southern Brazilian Shelf (SBS) as a possible spot to harvest the energy from the currents.

Sequence boundaries defined by regional unconformities in mixed carbonate/siliciclastic sediments have a variable duration from the margin to the interior of the Florida Platform. Factors controlling the timing and duration of these unconformities include a combination of global (eustatic) and regional mechanisms (sediment supply, current intensification). Integrated chronostratigraphies developed from a transect of continuous cores in the south-central interior to the southern margin of the Florida Platform show an increase in duration of the hiatal gaps along correlative sequence boundaries toward the platform edge. Two sequence boundaries are correlated across the south Florida Platform and mark formation contacts. The lower sequence boundary (SB-A) marks the Suwannee Limestone/Arcadia Formation contact and is of significantly less duration in the platform interior (southwest peninsular Florida, ∼2.0 m.y.) than at the south platform margin (middle Florida Keys, ∼8.1 m.y.). The hiatal gap along the upper sequence boundary (SB-B), marking the Arcadia Formation overlain by Miocene–Pliocene sediments that vary in age and composition regionally, records the same increase from the central part of the platform (southwest Florida, Arcadia Fm/Peace River Fm, ∼1.6 m.y.) to the south platform edge (lower Florida Keys, Arcadia Fm/Stock Island Fm, ∼11.5 m.y.). Eustatic fluctuations affected the relative sedimentation rates of the mixed sediments in the platform interior and at the margin. Most notably, the large eustatic fall at the end of the Early Oligocene terminated carbonate deposition of the Suwannee Limestone (SB-A). Sediment accumulation on the platform interior was more temporally continuous than at the margin because of greater siliciclastic input from the north. The strengthening of marine currents beginning in the Middle Miocene limited sediment accumulation across the southern platform margin (SB-B) and possibly caused erosion of the margin carbonates, increasing the duration of the hiatal gap on top of the Arcadia Formation.

The hydrological structure and the seasonal variability of marine currents in the Tyrrhenian Sea, off the coasts of Latium, are analysed using a data set obtained during several cruises between February 1988 and August 1990. Of particular interest is the fact that the hydrological surveys show the intermittent presence of a current of Levantine Intermediate Water (LIW) flowing anticlockwise along the Italian slope, at 250-700 m. This current is of particular importance in inferring the pathways of the Levantine Intermediate Water in the western Mediterranean Sea and in particular in the Tyrrhenian basin, downstream of the Strait of Sicily. These phenomena remain an open problem: our observations give support to the Millot's proposed general scheme, on the existence of a general cyclonic circulation of the LIW from the Strait of Sicily to the western Mediterranean, as opposed to a direct injection of LIW towards the Algerian basin., La structure hydrologique et la variabilité saisonnière des courants marins de la mer Tyrrhénienne, au large des côtes du Latium, sont analysées en utilisant des données obtenues pendant plusieurs croisières, entre février 1988 et août 1990. Le fait particulièrement intéressant est que ces recherches hydrologiques démontrent une présence intermittente du courant LIW (Eau intermédiaire Levantine-Levantine Intermediate Water), circulation cyclonique le long de la pente italienne, à une profondeur de 250 à 700 m. Le courant est particulièrement important pour déduire les trajectoires de l'eau LIW de la mer Méditerranée occidentale et, en particulier, dans le bassin Tyrrhénien, suivant le courant du canal de Sicile. Ces phénomènes représentent encore aujourd'hui un problème ouvert. Nos observations confirment le schéma général proposé par Millot sur la circulation générale cyclonique de l'eau LIW du canal de Sicile vers l'ouest de la mer Méditerranée, contrairement à l'entrée directe de l'eau LIW dans le Bassin algérien.

A brief overview of studies on the problem of marine slicks and their radar signatures carried out at the Institute of Applied Physics RAS is given. Synthetic aperture radar (SAR) slick imagery and physical mechanisms of slick formation due to different oceanic processes are considered, including slicks due to oceanic internal waves, non uniform coastal currents, algae bloom. Results of field studies slicks associated with these processes, and theoretical analysis of physical mechanisms of the slicks in SAR imagery are presented.

This paper presents experiments and measurements on a low speed permanent magnet cable wound generator for marine current energy conversion. Measurements were made for no load and nominal load (4.44 Ω/phase) conditions at nominal speed (10 rpm). For either load condition, the magnetic fields in the air gap were also measured. The measurements on the generator were compared with the corresponding finite element method simulations used to design the machine. It is shown in the paper that measurements and corresponding case simulations show good agreement. At nominal speed, the measured and simulated load voltages (nominal load) differ less than 1% for the rms values and less than 5% for peak values. At no load, measured and simulated voltages had larger differences, that is

This paper introduces a new semi-quantitative method to model a landscape assessment, by using a fuzzy analysis approach. The main aim of this research is to evaluate the landscape impact of the Kobold prototype in the Straits of Messina. The Kobold turbine, patented in 1998, is a prototype used to extract energy from the marine currents utilizing a vertical axis turbine. The site where the plant is positioned is very close to Ganzirri (Italy), on the Straits of Messina, near the Sicilian coast, at a distance of about 150 – 200 m from the shore. The results allow us to state that the measure of the impact landscape has been a huge success. In fact, the fuzzy variable representing the impact is 98% below the tolerance threshold.

Marine seismic data have been traditionally contaminated by bulge waves propagating along the streamers that were generated by tugging and strumming from the vessel, paravanes, tail buoys, and lead-in cables. With the progress of streamer technology bulge-wave interference has been significantly reduced. However, weather and flow noise still affects marine seismic data. The level of cross-flowinduced noise is increased when the data are acquired during turns or along circles, like in Coil shooting, and when marine currents are strong. In this paper, we present a new technique to attenuate towed-streamer noise acquired in these conditions. The method has been used successfully to process coil and wide-azimuth data in the Gulf of Mexico and offshore Brazil.

Se presenta el estudio preliminar del fitoplancton marino y la fauna coralina de la Isla Malpelo, en el Pacífico colombiano durante el crucero oceanográfico “Henry Von Prahl” efectuado en octubre de 1990. Se relaciona la información oceanográfica y geológica de la Isla y la influencia de las corrientes marina en la distribución de la fauna de la Isla. Se estableció la estructura de la comunidad de decápodos asociados al coral Porites capitata (doninancia de familias y densidad de individuos), en la Isla Malpelo y se discute su importancia como posible bioindicadora del efecto del fenómeno “En Niño”, sobre los ecosistemas de la Isla.

This chapter gives an overview of the various forms of hydropower: conventional hydropower, marine currents, tides, power from salinity gradients, ocean thermal energy conversion and wave power. This chapter gives an overview of the various forms of hydropower: conventional hydropower, marine currents, tides, power from salinity gradients, ocean thermal energy conversion and wave power.

The detailed palaeogeographic and stratigraphic knowledge of the earliest Pliocene Orb ria permits a good understanding of pollen sedimentation, especially of bisaccate coniferous pollen, with reference both to the plant distribution and to pollen dispersal factors. In such a coastal sedimentary situation that is entirely dependent in river action, bisaccate coniferous pollen — generally connsidered to be favoured by aerial transport — are predominantly carried by fluvial activity and transferred to the marine currents.

Daily mean values of meteo-oceanographic parameters are used to compute evaporation and heat fluxes between the sea and the atmosphere in the Gulf of Trieste during 1988. Incoming solar radiation, long-wave radiation, latent and sensible heat fluxes are considered in the total heat budget. The contribution of the single parameters entering each formula is examined and a comparison between the results from different evaporative formulae is performed. The total heat budget for the year considered gives a net loss of energy of 21 W/m2 which must be supplied by the heat transported by marine currents. The balance is positive for the sea surface from April to July, negative for the remaining period. Long-wave radiation accounts for the 45% of the total heat loss, latent heat for 53% and sensible heat for 2%. Computed annual mean evaporation is 1058 mm, with high peaks of more than 15 mm/day during strong Bora wind events. Evaporation slightly prevails on precipitation giving a net water loss of 30 cm. A comparison with what is found in the literature shows these results representative of the entire North Adriatic Sea. They confirm that this basin represents a sink of heat whose role in the general Mediterranean circulation consists in trasforming surface warmer waters coming from South in denser ones.

A low-speed permanent magnet (PM) cable wound generator for electrical energy conversion from marine or tidal currents has been designed and constructed. A key feature of this variable speed direct drive generator is its capability to efficiently generate electricity from tidal currents with very low velocities, in the order of 1 m/s. In arriving at an appropriate design for the generator typical characteristics of tidal currents were considered. Using these characteristics as input, and accounting for the electromagnetic losses, detailed computer simulations using a finite-element method software were carried out to come up with the final design. Various parameters that can influence the generator design are presented. An experimental set-up has been constructed based on the above-mentioned design in order to study the electrical and mechanical performance of the generator through a variety of experiments. The power input for this set-up is a variable speed motor, capable of operating the generator at rotational speeds of 0–16 r/min, representing tidal currents with very low velocities. The generator presented in this paper may be beneficial for a better understanding of an appropriate design and layout of tidal energy conversion systems.

Steel catenary risers (SCRs) are commonly used for deepwater oil and gas developments and the most economic material of construction is generally carbon manganese (C-Mn) steel. These risers suffer cyclic loading principally due to vessel movements, and vortex induced vibration (VIV) from passage of marine currents. For this reason, close attention is paid to fatigue design and girth weld quality, and fatigue testing is commonly carried out on procedure test welds. A further advantage of C-Mn steel is that good quality welds can readily be made, and more importantly, freedom from defects can be assured by reliable ultrasonic inspection. In sweet corrosive environments, when significant hydrogen effects would not be anticipated, a range of environmental effects on fatigue could be envisaged under different conditions, and at different stages of fatigue crack growth. For example, in early stages of growth, corrosion could blunt crack tips, and therefore slow the growth rate, whereas under other circumstances, or later in life, corrosion could provide additional crack extension, and accelerate growth. It has been demonstrated in this programme of fatigue crack growth rate and endurance testing that the most aggressive conditions in terms of corrosivity may not give shortest fatigue lives in testing. The results of tests comparing behaviour in air and in a very highly corrosive aqueous environment at 60°C saturated with CO2 (conditions which could not be sustained in production) have been explained by reference to competing effects of fatigue and corrosion. Comparison has been made with other published data. Important safety implications surrounding conditions for project-specific corrosion fatigue testing for riser design are considered.Copyright © 2008 by TWI

The world's first commercial‐scale grid‐connected tidal current energy installation will feature the Seagen marine current turbine developed by Marine Current Turbines Ltd. With potential for the manufacture of significant numbers of such devices there is a need to assess their environmental impact and, in particular, their life cycle energy and carbon dioxide (CO2) performance. This paper presents an analysis of the life cycle energy use and CO2 emissions associated with the first generation of Seagen turbines. The detailed assessment covers the embodied energy and CO2 in the materials and manufacturing of components, device installation, and operation along with those for decommissioning. With relatively conservative assumptions, and despite the early stage of development, the study shows that at 214 kJ/kWh and 15 g CO2/kWh, the respective energy and carbon intensities are comparable with large wind turbines and very low relative to the 400 to 1000 g CO2/kWh typical of fossil‐fuelled generation. The energy payback period is approximately 14 months and the CO2 payback is around 8 months. The embodied energy and carbon show limited sensitivity to assumptions with environmental performance remains excellent even under the most adverse scenarios considered. Materials use is identified as the primary contributors to embodied energy and carbon with shipping also significant. Improvements in the environmental impact of the Seagen can be achieved primarily by increased structural efficiency and the use of alternative installation methods to increase recovery of steel at decommissioning.

International audience; Despite increasing evidence that marine predators associate with mesoscale eddies, how these marine features influence foraging movements is still unclear. This study investigates the relationship of at-sea movements of king penguins to mesoscale eddies using oceanographic remote sensing and movement data from43individual trips over 4 years. Simultaneous satellite measurements provided information on gradients of sea surface temperature and currents associated with eddies determined from altimetry. Penguins tended to swim rapidly with currents as they traveled towards foraging zones. Swimming speed indicative of foraging occurred within mesoscale fronts and strong currents associated with eddies at the Polar Front. These results demonstrate the importance of mesoscale eddies in directing foraging efforts to allow predators to rapidly get to rich areas where high concentrations of prey are likely to be encountered.When returning to the colony to relieve the incubating partner or to feed the chick, the birds followed a direct and rapid path, seemingly ignoring currents.

Publisher Summary This chapter focuses on the assessment of a substance’s concentration in agricultural produce and freshwater fish, the food intake, and the impact assessment. The chapter considers different types of produce (e.g., potatoes, cereals, spinach), pork, poultry, eggs, beef and dairy products, and freshwater fish in the analysis. It has been argued that drinking water is excluded basically because of data availability constraints. As regards fish, only freshwater fish is included albeit most of the fish eaten in Europe stems from sea catches. The disregard of exposure via marine fish is because of the fact that sea fish is caught at very different places that would bring about the necessity to (a) assess the environmental fate of especially long-lived chemicals at the global scale (i.e., modelling the entire oceanic system on Earth) because of marine currents and migrating animals, and (b) to include rather detailed trade patterns. The chapter presents that ingestion rates are formulated as consumption of an average individual of the population—that is, without distinguishing among, for example, different age groups. Although consumption habits and amounts as well as body weight will be different between adults and children, there is no effect model available taking into account that effects occurring because of oral exposure to the substances investigated are prevalent for one population subgroup or the other.

Al, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti and Zn concentrations have been determined in surface sediment samples collected in the Taranto Gulf (Ionian Sea, Southern Italy) in order to evaluate their levels and spatial distribution in this important area of the Mediterranean Sea. For various metals, the geoaccumulation index has been calculated as a criterion to assess if their concentrations represent contamination levels or can be considered as background levels. The results show that metals concentrations in sediments can be considered near the background levels found in the Mediterranean Sea. Analytical results have been elaborated by using a Geographical Information System (GIS) software to show metals accumulation areas. Using multivariate statistical analysis, we evaluate the possibility to distinguish the sampling stations, in relation to their geographical position. Results have showed metals distribution in the Taranto Gulf is principally influenced by industrial and urban wastes, located mostly in the northern coastal area of the Ionian Sea. Rivers in the Basilicata region and prevailing anticlockwise marine currents are further factors influencing metal accumulation in sediments.

The progressive onlap of marine Lower Jurassic sediments onto the Bohemian and Vindelician Landmasses in SE-Germany indicates a major transgression, which reached its deepest phase during the Toarcian. On this overall deepening trend several minor shallowing/regressive events are superimposed. It is herein shown that correlation of these shallowing-deepening cycles over relatively large areas is possible. This indicates further that most of the shallowing and deepening events in the Upper Sinemurian and Pliensbachian were caused by eustatic changes in sea level, although locally other factors (e.g. tectonics, sediment supply, marine currents) may obliterate eustatic fluctuations.

Concentrations of metals (Al, Fe, Ti, Ni, Mn, Cr, Zn, Cu, Pb) were determined in surface sediments from Taranto gulf (Ionian Sea, Southern Italy) in order to assess the distribution and the bioavailability of metals. Total metal content and speciation of Fe, Ni, Mn, Zn, Cu and Pb were determined. Sediment cores were also sampled in some stations of particular interest. The analytical results show that metals distribution does not show significant variations in relation to depth. Metal distribution in the Taranto gulf is mainly influenced by industrial wastes from Taranto town, by rivers of the Basilicata region and by prevailing anticlockwise marine currents. These factors cause an accumulation of metals in the sediments near to the coasts of Calabria. The statistical analysis, effected by HCA and PCA methods, can be considered a good starting point in order to classify sediment samples and to locate accumulation areas. Metal speciation shows that Fe, Ni and Zn are present in sediments mainly as sulphides, Mn is present principally in an ion-exchange form or bound to carbonate, while Cu and Pb are mainly present in the fraction bounds to humic acids.

Deep marine currents are strongly influenced by climatic changes. They also deposit, rework, and sort sediment, and can generate kilometer-scale sedimentary bodies (drifts). These drifts are made of thoroughly bioturbated, stacked sedimentary sequences called contourites [Gonthier et al., 1984]. As a consequence, change in the direction or intensity of currents can be recorded in the sediments.

Marine currents may represent a renewable energy source characterized by a limited environmental impact. In Italy, the Strait of Messina seems to be suited for exploitation of this energy source. A vertical axis turbine, with blades oscillating about the pivotal axis according to the Voith–Schneider system, has been considered. This paper presents a preliminary theoretical investigation of the performance of this kind of turbine that may be employed to tap marine currents energy sources. The investigation is conducted by means of a simple momentum model based on the “single-disk single-streamtube” approach. The theoretical results are compared with experimental measurements. The adequate agreement between experimental and theoretical results shows that such a simple model may be able to predict the power coefficient and the operating range of the turbine.

Tbis paper describes tbe fossils, materials and paleoenviromnental conditions found in some outcrops near tbe town of Jesús María, Turrialba, Costa Rica. Tbe rock materials (reefal limestone, sandstones and conglomerates) are associated to tbe Punta Pelada Forrnation of Upper Oligocene tu Lower Miocene age. Outcrops are of reduced extent and are unevenly distributed, hence tbey are considered as patch reefs developed by enviromnental energy fluctuations, sea level changes and clastic sedimentation from sources on small islands acting togetber in narrow platforrns. Tbe structural and enviromnental characteristics where fossil communities developed were derived from tbe analysis of 460 samples containing 36 species. Tbe reefs represent low diversity communities comprising four coral species (three of tbem reef builders), 31 mollusks species (21 gastropods: a new species, 14 camivores, three herbivores and three of uncertain feeding habits; 10 bivalves species: five endobentbic and five epibentbic); algae ( at least three groups represented); sea urchins; foraminifers; crabs. Tbe eveuness index is low, mainly regarding tbe Scleractinian corals, where Antiguastrea cellulosa predominates (80% óf tbe recognized forrns). Tbe fossil assemblage suggests tbat tbe comm\lnities developed in shallow marine enviromnents (50-80 m deptb), affected by sea level changes, strung marine currents and clastic imput from nearby small islands. This paper describes tbe fossils, materials and paleoenviromnental conditions found in some outcrops near tbe town of Jesús María, Turrialba, Costa Rica. Tbe rock materials (reefal limestone, sandstones and conglomerates) are associated to tbe Punta Pelada Forrnation of Upper Oligocene tu Lower Miocene age. Outcrops are of reduced extent and are unevenly distributed, hence tbey are considered as patch reefs developed by enviromnental energy fluctuations, sea level changes and clastic sedimentation from sources on small islands acting togetber in narrow platforrns. Tbe structural and enviromnental characteristics where fossil communities developed were derived from tbe analysis of 460 samples containing 36 species. Tbe reefs represent low diversity communities comprising four coral species (three of tbem reef builders), 31 mollusks species (21 gastropods: a new species, 14 camivores, three herbivores and three of uncertain feeding habits; 10 bivalves species: five endobentbic and five epibentbic); algae ( at least three groups represented); sea urchins; foraminifers; crabs. Tbe eveuness index is low, mainly regarding tbe Scleractinian corals, where Antiguastrea cellulosa predominates (80% óf tbe recognized forrns). Tbe fossil assemblage suggests tbat tbe comm\lnities developed in shallow marine enviromnents (50-80 m deptb), affected by sea level changes, strung marine currents and clastic imput from nearby small islands.

The BBT-NEYRPIC currentograph is an autonomous instrument which records the speed and direction of marine currents. It comprises a Dumas-Neyrpic currentmeter, a speed recorder and a device for recording direction.

Keywords: Palk Bay, Palk strait,sethusamudram,shipping canal,Sri Lanka J. Natn.Sci. Foundation Sri Lanka 2005 33(4): 225-232 Doi: 10.4038/jnsfsr.v33i4.2111

A nonlinear model of generation of internal «solitary» marine waves is discussed: when a large surface wave—for instance a superficial wave or a bore of tidal origin—passes over a submarine mountain or crosses a strait, packets of internal waves may often be detected. We study this phenomenon taking into account the effect of the air-sea surface; we show that the phenomenon can be schematized, in an approximate but realistic way, by using the solutions of an inhomogeneous KdV equation. The forcing term depends on the air-sea surface elevation and on the bottom topography. We then apply our model to the marine currents, of tidal origin, flowing through the straits of Gibraltar.

Many T, S, O2, marine currents and meteorological data, observed with modern techniques and instruments, have been collected by the Institute of Meteorology and Oceanography in the Bay of Naples from 1977 on. Even, if the variability was large, some flow patterns were recognized as well as changes in the trend of currents: a periodicity of 3 to 7 days resulted all the year round with an oscillation of about 18 hours superimposed on it in summertime. The flow patterns resulted from current records and water mass analysis. When the open sea currents are flowing to SE the inner waters of the bay are cut off in a slow cyclonic gyre which leaves the coastal waters in a still slower motion making high pollutant concentration possible. The open sea currents flowing toward NW have branches entering into the bay which provide a fair renaewal of waters. The knowledge we have now of the South-Tyrrhenian surface marine currents indicates prevailing NW flow, hence giving one element in favour of a more or less active renewal of the waters in the bay. NE and WSW winds provided two simple models of water moving from the East coast toward the open sea: the former following the stress of the wind and the latter following the piling up of water along the coastal area.

A discussion leads to the conclusion that the coastal desert of Southern Angola is really due, as thought before, to a coastal upwelling of cold water, although Portuguese and Russian hydrological surveys off the coast have shown the (occasional ?) presence of a North-South, warm current (the so-called Angola current) and brought complications in the traditional model. It may be that the heavy rains observed sometimes in March at Baia dos Tigres and Mossamedes would be due to a meandering of the warm current, reaching temporarily the coast and suppressing the upwelling., Une discussion mène à conclure que le désert côtier du sud de l'Angola est réellement dû, comme on le pensait, à un upwelling côtier d'eau froide, bien que des campagnes hydrologiques portugaises et russes aient montré, un peu plus au large, la présence (occasionnelle ?) d'un courant chaud nord-sud, appelé courant d'Angola, et introduit des complications dans le schéma traditionnel. Il se peut que les grosses averses observées parfois en mars à la baie des Tigres et à Mossamédès, seraient dues à des méandres dudit courant chaud, qui atteindraient momentanément la côte et supprimeraient l'upwelling., Guilcher André. Problèmes climato-océanographiques du désert côtier d'Angola particulièrement la baie des Tigres (16° 35'S). In: Norois, n°116, Octobre-Décembre 1982. pp. 507-517.

The marine currents inside the archipelago of La Maddalena between Sardinia and Corsica islands have been studied. The results of an implicit numerical barotropic unidimensional model are discussed and compared with experimental data.

It has commonly been assumed that the terebratuloid and rhynchonelloid brachiopods found in Mesozoic and Tertiary formations are entombed on the site of growth. Recent work on members of the genus Hamptonina from the Great Oolite (Jurassic) at Bath (England), and a study of the literature on other localities lead to the conclusion that these brachiopod shells have often been transported by marine currents after the death of the organism.

The so-called strandflat of the Norwegian coasts has aroused the interest of scientists since an early date. Later other forms, such as banks or grounds and deep channels, were discovered and posed additional problems. But no agreement has ever been reached on these problems in spite of numerous discussions. The formation and processes in the development of the strandflat and adjacent geomorphological forms cannot-according to the author-be separated from the history of the hinterland. Thus, to a major extent, the strandflat forms a part of a polycyclic piedmonttreppe. In the same way the bankflat is stated to be identical with one step of this geomorphological staircase. The banks and grounds off the coasts are explained as galacial-fluviatile-marine deposits of a very complex nature, intersected by longitudinal and transverse channels. These peculiar submarine forms are suggested as having been created by fluvial and glacial erosion and conserved to our day by a system of marine currents. Isostatic and ...

The $O^{18}/O^{16}$ analysis of the $C_aCO_3$ of fossil Foraminifera shells is applied to the study of paleotempera-tures and thermic variations in the Lower Pleistocene Lomita marl of southern California. Temperatures of shallow waters varied from 12° to 30° C, with one main period of colder and one of warmer temperatures. These variations are thought to have been produced mostly by interaction of marine currents and local tectonics.

An Unscented Kalman Filter (UKF) able to estimate the direction and the magnitude of a priori unknown marine currents is described in the paper; the currents estimation is performed during the navigation of an Autonomous Underwater Vehicle (AUV) together with the estimation of the vehicle navigation state. The filter here proposed is born augmenting the state of an UKF previously developed by the same authors. The proposed approach is validated offline exploiting the data of the onboard sensors of MARTA AUV (MArine Robotic Tool for Archaeology), collected during recent sea trials in La Spezia, Italy. In the near future the algorithm will be implemented onboard the vehicle to carry out an online estimation of the marine currents.

(1881). On the influence of the marine currents in the geographical distribution of the Amphibious Mammalia, and particularly of the eared seals. Annals and Magazine of Natural History: Vol. 8, No. 43, pp. 70-72.

The comparison of marine dispersion model results with measurements is an essential part of model development and testing. The results from two residual flow models are compared with seawater concentrations, and in one case with concentrations measured in marine molluscs. For areas with short turnover times, seawater concentrations respond rapidly to variations in discharge rate and marine currents. These variations are difficult to model, and comparison with concentrations in marine animals provides an alternative and complementary technique for model validation with the advantages that the measurements reflect the mean conditions and frequently form a useful time series.

The comprehensive plan for the treatment of wastewaters for the Costa del Sol envisages the construction of a series of purification plants, in most of which the sewage will be treated for the removal of suspended and floating solids. This plant affects two zones each 100 km in length, situated to the east and west of Malaga. The water will be conveyed to the sea in a condition and at a point suitable for discharge to the sea. The work described is a study of marine currents, determined by the injection of a radioactive tracer (Bromine 82) at points suitable for the discharge of the wastewater. Over a period of 2 years 146 tests have been carried out which will provide ample information to give the necessary information concerning the dilution which the various parameters of pollution will receive – parameters of quality, velocity of movement and dispersion. Interpretation of the results will be realised according to a two dimentional model of radial stmmetry, based on transforming isoconcentration curves, irregular in form, into circles of equal area. Incorporating into this model the statistical model of the parameters previously referred to, it was possible to obtain curves of isoprobability of predetermined factor of dilution at the zone near the point of discharge to the sea. The model was proved comparing the geomatical form of local discharges with the results predicted by the mathematical model. The results were satisfactory.

At Pointe Noire, Gulf of Guinea, the anomalously large annual range of mean air temperature (6° C) is explained by an even larger range of sea surface temperature (more than 7° C), which derives from cold advections from June to September. Such cold advections result in an absence of rainfall during these months (fig. 1), as in the classical tropical coastal deserts (Peru, etc.), but for a shorter time., A Pointe-Noire, Golfe de Guinée, l'amplitude thermique annuelle de l'air, qui est anormalement grande (6° C), s'explique par une amplitude encore supérieure de la température de l'eau de mer de surface (plus de 7° C), qui provient d'advections d'eau froide de juin à septembre. De telles advections froides déterminent une absence concomitante de précipitations pendant ces mois (fig. 1), comme dans les déserts côtiers tropicaux classiques (Pérou, etc.), mais pendant une durée plus courte., Guillerm Jean-Maurice. Un cas d'exagération de l'amplitude thermique annuelle de l'air par influence océanique : le golfe de Guinée à Pointe-Noire. In: Norois, n°116, Octobre-Décembre 1982. pp. 499-505.

As a result of the weathering of the continents by agents of erosion, erosion products are transported by water currents from the land surface to the marine environment. The progress of these particles, whether detrital or ionic, will be examined here in terms of the marine currents. Modifications to the particles during transportation from the continental to the marine environment will also be considered. The marine environment can be regarded as a transportation environment, as an environment of mineral formation, and finally, when the motive force of the currents is no longer sufficient for transportation, an environment of sedimentation. Thus, a sedimentation environment is defined by its position in the sea (i.e. by its depth and distance from the coast) and by the force of the currents that affect it.

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