Interactions among metals in the spectrochemical determination of trace amounts of cadmium in marine mussels     

A. Mazzucotelli  A. Viarengo  G. Martino  R. Frache 《Marine environmental research》1988,24(1-4)

The determination of trace amounts of inorganic elements by electrothermal atomic absorption spectrophotometry (ETA-AAS) or inductively coupled plasma atomic emission spectrometry (ICP-AES) suffers from some kinds of interference due to the inorganic fraction of the matrix of many environmental samples. The ratio between a major matrix element and the analyzed trace element plays an important role in the spectrochemical behaviour of the latter. The resulting enhancing or depressing effect also gives rise to severe faults when the well known standard addition method (SAM) is used. The present work shows the interactions due to the presence of elements such as calcium, sodium, potassium, magnesium and iron during the spectrochemical determinations of trace amounts of cadmium in marine mussels. A possible liquid anion exchange extraction is suggested for the analysis of cadmium by ETA-AAS.  相似文献   

Hypothesis for a submarine landslide and cohesionless sediment flows resulting from a 17th century earthquake-triggered landslide in Quebec,Canada     

C. T. Schafer  John N. Smith 《Geo-Marine Letters》1987,7(1):31-37

Textural isotopic and microfossil data from two gravity cores obtained in Saguenay Fjord, Quebec, suggest that a distinctive sandy clay bed was deposited as the result of a major landslide in the Saguenay River basin. Pb-210 dating of the cores indicate that the bed is of similar age to the magnitude 7 earthquake of February 5, 1663. The slide involved sensitive marine clays and may have occurred in two stages. Slide sediments carried into the Saguenay River channel were probably reworked and subsequently transported down the Fjord basin as two distinct cohesionless mass flows. Fine clay laminae that overlie the older mass flow bed record the modulation of depositional processes by tidal currents for several weeks after this event.  相似文献   

Sea-level, sediment supply and coastal changes: Examples from the coast of Ireland     

R.W.G. Carter  T.W. Johnston  J. McKenna  J.D. Orford 《Progress in Oceanography》1987,18(1-4)

Sediment supply and pre-existing shoreline morphology are crucial factors in controlling coastal changes due to sea-level rise. Using examples from both southeast and northeast Ireland, it can be shown that sea-level change may trigger a sequence of events which leads to both static and dynamic shoreline equilibrium. Cliff erosion and longshore sediment movement in east Co. Wexford has led to injection of sediment onto the shelf, and the growth, under both wave and tide regimes, of linear offshore shoals. These shoals now control the pattern of shoreline erosion and provide a template for possible stepwise evolution of the coast under any future sea-level rise. In contrast, the nearby coast of south Co. Wexford comprises a series of coarse clastic barriers moving monotonously onshore, via overwash processes. Here the behavior of the barrier is conditioned by the antecedent morphology of both the beach face and stream outlet bedforms. Finally, the rock platform coast of Co. Antrim presents a far more resistant shoreline to incident marine processes, yet even here there is strong evidence of present process control over so-called ‘raised’ platforms and embayments. It is concluded that coastal sediment supply and dynamics, together with coastal morphology and its interaction with waves, present a far more complex variety of sea-level indicators than is normally acknowledged.  相似文献   

Seasonal Variation in the Biomass of Marine Macrophyta from Greek Coasts     

S. Haritonidis    G. Nikolaidis  I. Tsekos 《Marine Ecology》1986,7(4):359-370

Abstract. The marine plant communities of the littoral zone in different biotopes of the Greek coasts were investigated in 1980-81. Seasonal distribution and variation of marine plant biomass were assessed. The communities of Cystoseira crinita and C. compressa were outstanding with maximum biomass during the summer months. Corallina officinalis and Pterocladia capillacea + Viva rigida communities predominated with maximum biomass in autumn and exhibited a decrease in winter, except in stressed biotopes. The species diversity and productivity of seaweeds along the Greek coasts are interpreted in relation to a number of environmental parameters.  相似文献   

Past and present sedimentary activity in the Capbreton Canyon, southern Bay of Biscay     

M. Gaudin  T. Mulder  P. Cirac  S. Berné  P. Imbert 《Geo-Marine Letters》2006,26(6):331-345

Located in the south-eastern part of the Bay of Biscay, the Capbreton Canyon incises the continental shelf up to the 30 m isobath contour, and acts as a natural conduit for continental and shelf-derived sediments. EM1000 multibeam bathymetry shows two main features characterising the canyon — a deeply entrenched meandering channel, bordered by fluvial-like terraces constituting large sediment traps. A dataset of cores and seismic profiles together with a multibeam bathymetry map has enabled the characterisation of recent sedimentary activity in the axial channel and on the terraces. Data analysis evidenced the major role of the canyon head in recent sediment dynamics. This part of the canyon is a temporary reservoir for sediments, accumulated by coastal hydrodynamic processes. Exceptional climatic, tectonic or hydrodynamic events can mobilise the sediments and generate gravity-driven flows. Under the present-day sea-level highstand conditions, these flows are not powerful enough to bring their bedload to the deep sea, and are confined mainly to the upper part of the canyon. Turbidity currents model the axial channel pathway and are at the origin of terrace formation. Terraces in the Capbreton Canyon are not typical but rather are reduced to confined levees. Three factors control the vertical growth of a terrace: (1) the amount of overspilled sediments brought by turbidity currents, (2) hemipelagic sedimentation and (3) terrace height. The amount of sediment spilling over a terrace decreases with increased terrace elevation. Concurrently, the proportion of hemipelagic fallout depositing on a terrace increases. Terraces are considered to be fossil when the height of the terrace prevents further deposition by overspilling. The terraces studied in this paper are interpreted as having formed during the Holocene, implying that the sediment dynamics of the Capbreton Canyon is continuous through time. Highstand periods differ from lowstand periods because they show a decrease in the energy of erosive processes. Temporal variations in erosive and depositional processes in the canyon are controlled by the Adour River, which delivers large amounts of sediment to the system.  相似文献   

Experimental study of the fine structure of the wind field near a rough surface     

I. N. Ivanova  O. N. Mel’nikova  T. A. Nivina  K. V. Pokazeev 《Izvestiya Atmospheric and Oceanic Physics》2006,42(5):646-652

The air-flow velocity field near the water surface is studied in the zone of wind-wave intensification. Caused by a periodic separation of eddies, a nonzero time-averaged value of the wind velocity in the near-water streamline is detected at the leading slope of the wave. The distribution of pressure along the wave with allowance for the vertical velocity shear and disturbances produced by eddies and a periodic deceleration of the viscous layer was calculated with the aid of the Cauchy-Lagrange integral. This procedure made it possible to calculate the growth rate of the wave amplitude, whose value was found to be close to its experimental value at the initial stage of acceleration.  相似文献   

Simulation of additive transport from the land surface on the basis of experimental data on heat transfer in the atmospheric surface layer     

V. P. Kukharets  H. G. Nalbandyan 《Izvestiya Atmospheric and Oceanic Physics》2006,42(3):313-318

A method is proposed to study the transport of a passive additive in the atmospheric surface layer with the use of the atmospheric transfer function. This method makes it possible to estimate the spatial distribution of the concentration of a passive additive in the atmospheric surface layer from the additive’s surface source without experimentally determining the vertical profile of the transport coefficient or without resorting to various hypotheses for the character of its behavior. The transfer function, which contains the information on the wind-field structure, can be obtained from simple one-point measurements of surface-and air-temperature fluctuations and from subsequent spectral processing of the data. The effects of the wind-velocity profile and turbulence on the spatial distribution of additive concentration are assessed. This method allows one to simplify experiments during development and verification of the models of atmospheric diffusion. This method may also be useful in emergency situations to predict the propagation of hazardous additives.  相似文献   

Condition of coastal mesoplankton communities in the northeastern area of the Black Sea in 2005     

M. E. Vinogradov  L. P. Lebedeva  T. A. Lukasheva  L. L. Anokhina 《Oceanology》2006,46(6):817-826

The structure and distribution of mesoplankton in the northeastern part of the Black Sea along 6-mile and 100-mile sections in the area off Golubaya Bay (near the city of Gelendzhik) were analyzed. The studies were performed from R/V Akvanavt and the boat Ashamba. The observations were carried out during the vegetation season from the beginning of June to the first half of October 2005. Samples of mesoplankton were collected with use of a BSD net with an opening of 0.1 m² and a mesh size of 180 μm. Both the total (over the entire water column) and layer-by-layer (separately for the upper quasi-homogeneous layer, the seasonal thermocline, and the subthermocline layer) hauls were performed down to the bottom (at sea depths of less than 200 m) or down to the upper boundary of the hydrogen sulfide waters. The particular hydrophysical conditions that were observed in 2005 resulted in an approximately one-month advance of the phenological condition of the planktonic community as compared to the usual pattern. Beroe ovata appeared in the plankton at the end of July, the mass development of Mnemiopsis leidyi was suppressed, and the duration of its influence on edible zooplankton was essentially reduced. As a result, the total mesoplankton biomass in August–October 2005 was 1.5–2 times as great as that in 2004. The abundance of Acartia clausi increased approximately 4–5 times and the quantity of Sagitta setosa also considerably increased. At selected stations, Mnemiopsis leidyias, the main predator in the community, was replaced by Sagitta setosa.  相似文献   

A conceptual design of an underwater vehicle     

Carl T.F. Ross 《Ocean Engineering》2006,33(16):2087-2104

The paper presents a conceptual design of an underwater star wars’ system, which will be more difficult to detect by the enemy than a recently proposed ‘surface’ star wars’ system.The paper suggests that for the proposed structures needed for the underwater star wars’ system, the material of construction should be a composite and not a metal, as use of the latter for large deep diving underwater vessels will result in such structures sinking to the bottom of the ocean like stones, due to the fact that they will have no reserve buoyancy. The paper also shows that composites have better sound absorption characteristics, thereby making the underwater structures difficult to detect through sonar equipment. It is proposed that these underwater structures should operate up to a depth of 7.16 miles (11.52 km), as at this depth, all of the oceans’ bottoms can be reached.The author shows that current technology can be used to construct and operate such vessels, but more progress needs to be made with metal matrix and ceramic composites, so that the hulls of underwater missiles and torpedoes can be constructed in these materials.  相似文献   

Swimming endurance of haddock (Melanogrammus aeglefinus L.) at prolonged and sustained swimming speeds, and its role in their capture by towed fishing gears     

Breen  Mike; Dyson  Jamie; O'Neill  Finbarr G.; Jones  Emma; Haigh  Michael 《ICES Journal of Marine Science》2004,61(7):1071-1079

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