Southern elephant seal trajectories, fronts and eddies in the Brazil/Malvinas Confluence     

Claudio Campagna  Alberto R. Piola  Maria Rosa Marin  Mirtha Lewis  Teresita Fernndez 《Deep Sea Research Part I: Oceanographic Research Papers》2006,53(12):1907-1924

This study describes the association between transient, mesoscale hydrographic features along the axis of the Brazil–Malvinas Confluence, in the SW Atlantic, and the foraging behavior of 2–3-year-old (focal) juvenile southern elephant seals, Mirounga leonina, from Península Valdés, Argentina. Departing from the dominant pattern of foraging on predictable bathymetric fronts on the Patagonian shelf and slope, three females out of 12 satellite-tracked juveniles remained at the edge of young warm-core eddies and near the outer core of cold-core eddies, coinciding with the most productive areas of these temperature fronts. Seal trajectories along high-temperature gradients were always consistent with the speed and direction of surface currents inferred from the temperature distribution and confirmed by surface drifters. Movements of foraging seals were compared with those of surface drifters, coinciding in time and space and yielding independent and consistent data on regional water circulation parameters. The diving pattern recorded for one focal seal yielded shallower dives and a loose diel pattern in the eddy, and a marked diurnal cycle compatible with foraging on vertically migrating prey in the cold waters of the Malvinas Current. Pre-reproductive females that use the mesoscale fronts of the Argentine Basin as an alternative foraging area would benefit from lower competition with more experienced seals and with other top predators that reproduce along the coast of Patagonia.  相似文献   

Spatial patterns of mesozooplankton distribution in the Southwestern Atlantic Ocean (34{degrees}-41{degrees}S) during austral spring: relationship with the hydrographic conditions     

Marrari  Marina; Vinas  Maria Delia; Martos  Patricia; Hernandez  Daniel 《ICES Journal of Marine Science》2004,61(4):667-679

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On the analysis of dark fixation in primary production computations     

Petersen  G. Hopner 《ICES Journal of Marine Science》1979,38(3):326-330

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The dissociation constants of carbonic acid in seawater at salinities 5 to 45 and temperatures 0 to 45°C     

Rabindra N Roy  Lakshimi N Roy  Kathleen M Vogel  C Porter-Moore  Tara Pearson  Catherine E Good  Frank J Millero  Douglas M Campbell 《Marine Chemistry》1993,44(2-4)

The pK₁^* and pK₂^* for the dissociation of carbonic acid in seawater have been determined from 0 to 45°C and S = 5 to 45. The values of pK₁^* have been determined from emf measurements for the cell: where X is the mole fraction of CO₂ in the gas. The values of pK₂^* have been determined from emf measurements on the cell: The results have been fitted to the equations: where T is the temperature in K, S is the salinity, and the standard deviations of the fits are σ = 0.0048 in lnK₁^* and σ = 0.0070 in lnK₂^*.Our new results are in good agreement at S = 35 (±0.002 in pK₁^*and ±0.005 in pK₂^*) from 0 to 45°C with the earlier results of Goyet and Poisson (1989). Since our measurements are more precise than the earlier measurements due to the use of the Pt, H₂|AgCl, Ag electrode system, we feel that our equations should be used to calculate the components of the carbonate system in seawater.  相似文献   

Characterization and molecular analysis of hepatic microsomal UDP-glucuronosyltransferases in the marine fish, Pleuronectes platessa     

Douglas J Clarke  Brian Burchell  Stephen George 《Marine environmental research》1988,24(1-4)

Here we report the results of the first molecular enzymological study of fish UDP-glucuronosyltransferase (UDPGT). UDPGT activities of plaice liver microsomes were greatest for planar phenols and there was low but measurable conjugation of bilirubin, testosterone and androsterone. A highly purified preparation was isolated which possessed activities towards 1-naphthol, bilirubin and testosterone, containing several molecular weight species of M_r 52–56 kDa. On immunoblot analysis these proteins cross-reacted with a polyspecific anti-rat UDPGT antibody, suggesting that a number of plaice UDPGT isoforms with epitopes in common with the corresponding rat enzymes had been purified.  相似文献   

Mapping sediment acoustic impedance using remote sensing acoustic techniques in a shallow-water carbonate environment     

Donald J. Walter  Douglas N. Lambert  David C. Young  Kevin P. Stephens 《Geo-Marine Letters》1997,17(4):260-267

 Real-time trackline plots of surficial sediment acoustic impedance delineate several sedimentary facies off Garden Key in the Dry Tortugas. The sea floor within a 6×6 km surveyed area consists of carbonate muds (silts), sands and shell, rock, and live corals. The 4-kHz acoustic data supports this finding by providing a pictographic representation of the distribution and structure of several sediment facies types. Plotting the gridded acoustic data with commercial mapping software (Surfer) provides a three-dimensional (3D) perspective of the bottom topography with a color contour map of surficial sediment impedance (upper 0.4 m) draped over the 3D surface.  相似文献   

The distribution of total and electrochemically available copper in the northwestern atlantic ocean     

Douglas L. Huizenga  Dana R. Kester 《Marine Chemistry》1983,13(4):281-291

Copper in a series of samples from the northwestern Atlantic has been determined by anodic stripping voltammetry (ASV) and atomic absorption spectrometry after preconcentration by cobalt—APDC coprecipitation. Samples from a transect across the continental shelf directly off the New York Bight showed a linear relationship between total copper and salinity (31–34‰) and less than 5% of the total copper was detectable by ASV. A slope water station showed less than 9% of the total copper to be ASV detectable in the upper 780m, below which the ASV detectable copper increased to 70% at 3000 m. The Sargasso Sea profiles showed less than 7% ASV detectable copper in the upper 150 m; the fraction of the total copper detected by ASV increased to about 80% of the total copper at greater depths. The reduced availability of copper to the ASV measurement in coastal waters and open ocean surface waters appears to be related to recent contact with waters where biological productivity occurs.  相似文献   

Hydrocarbons in bivalve mollusks of Port Valdez, Alaska: Consequences of five years' permitted discharge     

David G. Shaw  Thomas E. Hogan  Douglas J. McIntosh 《Estuarine, Coastal and Shelf Science》1986,23(6)

Petroleum hydrocarbons were investigated in Mytilus edulis and Macoma balthica at six intertidal sites in Port Valdez, Alaska after three to five years of oil terminal operation. Information about the concentrations of total hydrocarbons, unresolved complex mixture, normal alkanes, isoprenoids, olefins, hopanes and polycyclic aromatic hyrocarbons shows that petroleum accumulation in these bivalve mollusks is greatest at the Valdez municipal boat harbor and a crude oil terminal which has been permitted to discharge 170 kg oil day⁻¹. Accumulation two- to ten-fold less were observed at 3 km from the terminal and boat harbor. The temporal trends in petroleum hydrocarbon concentrations in M. edulis and M. balthica reflect the effects of selective retention and depuration of different hydrocarbon classes as well as variation in hydrocarbon sources. It is not clear whether the petroleum concentrations in Port Valdez bivalves had reached steady state by 1982, the final sampling time reported here.  相似文献   

Quality of Nephrops as food for Atlantic cod (Gadus morhua L.) with possible implications for fisheries management     

Bjornsson  Bjorn; Alvaro Dongala Dombaxe  Maria 《ICES Journal of Marine Science》2004,61(6):983-991

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Dynamics of ship collisions     

Martin J. Petersen 《Ocean Engineering》1982,9(4):295-329

This paper described a procedure for simulation of the outer dynamics in ship collisions.The simulation procedure is derived using the transient equations for the horizontal motion of a ship. The hydrodynamic forces acting on the ships' hull during the collision are calculated by a strip method, where the forces acting on each section are described by means of unit response functions. These functions are determined by cosine transformation of the sectional dampings. The sectional added masses and dampings, and thereby also the sectional unit response functions, are calculated by an approximate method. The deformations of the slip structures during the collisions are modelled as non-linear springs.The resulting system of non-linear equations is solved using a numerical time-integration procedure.A number of different collision situations are simulated by means of the procedure.  相似文献