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861.
A. A. Bezborodov S. L. Gokchen V. N. Eremeev I. T. Konuk A. K. Saidam E. M. Tirasin 《Physical Oceanography》1991,2(3):227-231
The hydrological and hydrochemical structures of the upper 300 m water column of the Black Sea in autumn 1988 have been studied. Regularities in the distribution of the physico-chemical characteristics in the zone of interaction between aerobic and anaerobic waters as well as the topography of the H2S zone boundary and its connection with a certain density gradient have been found.Translated by Mikhail M. Trufanov. 相似文献
862.
Image processing techniques are discussed that correct distortions in GLORIA II side scan sonar imagery including water column
offset, slant-range distortion, multiple returns, aspect ratio, speckle noise, striping, and cross-track power drop-off. The
software operates within NASA's ELAS image processing system and is applied to the original 12-bit GLORIA II data. Procedures
are discussed for generating large scale mosaics and three-dimensional overlays with sea floor bathymetry. The results are
shown in four sonographs acquired off the southern coast of California. 相似文献
863.
Reproductive variability in North Sea plaice, sole, and cod 总被引:4,自引:1,他引:4
Rijnsdorp A. D.; Daan N.; van Beek F. A.; Heessen H. J. L. 《ICES Journal of Marine Science》1991,47(3):352-375
864.
The use of a system of continuous culture of phytoplankton at constant population density, the ‘cage-culture’ turbidostat, as a monitor of the bioavailability of pollutant materials, is illustrated. In the case of proposed dredge spoils from two polluted areas, it is shown that bulk analyses for scheduled materials cannot be equated with bioavailability. Monitoring for the effect of the whole pollutant mixture on a properly chosen test population could obviate the necessity for chemical analyses for each component. 相似文献
865.
采用直接分离法、稀释法和毛细管分离法等方法,从酒药和大曲中分离得到了几株高糖化力的根霉纯培养,并应用于“全曲清酒”的制作;用富含淀粉的甘薯为原料,可省略通常采用的复杂的“发酵”工艺过程,从而降低了成本,可在乡镇企业推广生产 相似文献
866.
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
867.
Accumulation of copper was studied between June 1979 and June 1980 in the oyster Ostrea edulis Linnaeus, cultivated in the Limski Kanal, on the Istria Peninsula (Yugoslavia).The copper distribution in different organs of oysters of the same age was compared with concentrations of copper existing in different physicochemical forms in ambient sea water, i.e., dissolved Cu in labile complexes determined at the natural pH of 8; ‘total’ dissolved Cu determined after acidification to pH 2; and Cu bound to suspended particles with a diameter above 0.45 μm. Copper concentrations in the water were determined by differential pulse anodic stripping voltammetry (DPASV) and in analyses of biotic material, graphite furnace atomic absorption spectrometry (GFAAS) was applied.Significant correlations have been found between copper complexed with dissolved organic ligands and its concentration in the soft part of the oyster. Copper contents increase gradually with the weight of the organs until enhanced gametogenetic activity of the oysters occurs. Thereafter the correlation factor between copper contents and the size of body parts varied significantly with the season. 相似文献
868.
Lawrence W. Harding Jr Blanche W. Meeson Thomas R. Fisher Jr 《Estuarine, Coastal and Shelf Science》1986,23(6)
Chesapeake Bay is a large and productive estuary that has received close scrutiny in recent years because of indications that its water quality and biota have been damaged by man's activities. Data on primary production for the estuary as a whole, however, are surprisingly sparse. We describe here the distribution of photosynthetic carbon assimilation by phytoplankton in Chesapeake Bay, and relate productivity patterns to hydrographic characteristics of the estuary. Between March 1982 and April 1983, a series of four cruises was conducted on Chesapeake Bay, and two cruises on the urbanized Delaware Bay for comparison. The upper Chesapeake and Delaware were highly turbid with high concentrations of suspended particulate matter and dissolved inorganic nutrients. Low chlorophyll concentrations were usually found in these areas of high turbidity, despite the abundance of nutrients, suggesting light limitation. Application of Wofsy's (1983) model of phytoplanton growth confirmed this suggestion. Chlorophyll and productivity maxima usually occurred seaward of the turbidity maxima where light penetration increased and suffient nutrients were present to support active phytoplankton growth. Further seaward of the chlorophyll maxima in the Chesapeake, the photic zone depth increased, concentrations of nutrients decreased, and phytoplankton biomass decreased, suggesting that nutrient availability, rather than light, controlled phytoplankton growth in the lower portion of the estuary. In contrast to the Chesapeake, Delaware Bay was more turbid, had generally higher nutrient concentrations, and was lower in phytoplankton productivity. The chlorophyll maxima and region of rapid phytoplankton growth occurred further toward the lower estuary and shelf regions in Delaware Bay because the high turbidity extended further seaward. Nutrients were never depleted at the shelf end of the estuary sufficiently to retard phytoplankton growth. Photosynthesis-irradiance (P-I) curves from simulated in situ and constant intensity incubations showed a strong correlation of the light-limited slope (aB) with the light-saturated rate (
) on each cruise. Spatial variations in
corresponded to patterns of phytoplankton abundance, as did integral production (PP) and carbon-based growth rates (μC, μm), and photosynthetic parameters varied significantly with temperature. 相似文献
869.
870.
Mercury concentrations in blue crabs (Callinectes sapidus) collected from an area of mercury-contaminated sediments in Lavaca Bay, TX, USA, are more than an order of magnitude greater than concentrations in penaeid shrimp from the same area. Laboratory feeding experiments using mercury-contaminated fish as food showed that both blue crabs and pink shrimp (Penaeus duorarum) could accumulate mercury concentrations comparable to those in their food in 28 days. Calculated mercury assimilation efficiencies averaged 76% for blue crabs and 72% for pink shrimp. Significant depuration of mercury by blue crabs was not observed during a subsequent 28-day period, but pink shrimp lost mercury at a rate of about 0.012 day-1. Model calculations predict biomagnification factors of mercury of about two to three at steady state for both species. The large difference in observed concentrations of mercury in field-collected blue crabs and penaeid shrimp does not result from differences in efficiency of mercury assimilation from their food or from differences in excretion rates. It is more likely the result of differences in residence times in the contaminated area and of differences in feeding habits. 相似文献