Morphological studies of the females of Calanus finmarchicus, C. glacialis, and C. hyperboreus were performed for specimens sampled in different areas of the Greenland, Barents, Kara, and Laptev seas. Intraspecific variability was found for the ratio of the specimens characterized by different types of setae patterns on the endopodites of C. glacialis and C. finmarchicus. The variability of this parameter did not relate to the environmental peculiarities of the sampling sites and did not depend on the temperature regime. We assume that such differences may be the result of the hybridization of C. glacialis and C. finmarchicus due to the similarity of their reproduction systems and the overlapping of the body size ranges. 相似文献
Results of studies of the surface-brightness distributions of a group of young stellar objects located within 16″ of the star θ1 Ori C are presented. Isophotes around each proplyd are constructed using violet, red, and near-infrared images. No regularity in the sizes of the diametral cross sections of the proplyds in the various photometric bands is observed. The measured relative intensities are converted to absolute fluxes, and the absolute luminosities of the brightest parts of the disks and of the disk peripheries are estimated. The ratio of the semi-major to the semi-minor axes of the objects range from 1.5 to 2.5. The maximum lengths of the proplyd tails in various filters range from 300 to 700 AU. They become shorter with decreasing distance from the illuminating star, possibly due to enhanced dissipation of the disk, due to the growth in the role of photovaporization.
Doklady Earth Sciences - The results of analysis of climatic peculiarities of the alongshore fluxes of bottom sediments are presented. The object of research is the coastal zone of the Hicacos... 相似文献
During autumn 1968 an oceanographic investigation was conducted in the region of the Subarctic boundary between 155°E and 180°. The geostrophic flow of the upper 500 m was remarkably similar in direction; hence the salinity-minimum, Intermediate water must have the same path of flow as water at the surface. A water mass analysis revealed a decrease in the percentage of Subarctic water to the south and east, plus an increase in the homogeneity of water to the east, which supports Reid's conclusions that the salinity minimum results mainly from lateral mixing in the pycnocline in this region. Salinity at the minimum increases toward the south and east, and the density at this level also increases slightly from the western to the central Pacific, perhaps as a result of unequal vertical mixing above and below the minimum. 相似文献
We collated information on the sources and sinks of organic carbon in Manukau Harbour, a shallow temperate estuary. Two contrasting inner harbor regions were considered; the northern region, which is urbanized and receives a major load of sewage wastewater, and the southern region, where allochthonous inputs are dominated by the runoff from small rural streams. Although high levels of dissolved nitrogen in the wastewater supported phytoplankton blooms in the northern region, total primary production there was similar to that in the southern region (ca. 300 g C m?2yr?1). By contrast, high concentrations of organic carbon in the wastewater resulted in an additional input to the northern region of 120 g C m?2 yr?1. Loads from runoff and streams to both regions were low. At 350 g C m?2 yr?1, total respiration in the northern region exceeded total production, so the region was slightly heterotrophic. Respiration was lower in the southern region (270 g C m?2 yr?1), which was net autotrophic. Some carbon was exported from each region to the outer harbour (50–80 g C m?2 yr?1). Dissolved oxygen levels in the northern region were somewhat depleted at times; and the high numbers of microzooplankton indicated consumption was enhanced there. Apart from a relatively small area of organic enrichment close to the wastewater discharge, benthic consumers in the harbor appeared to be limited by physical disturbance (by wind-waves) rather than by food availability. Improved wastewater treatment is expected to substantially reduce the allochthonous input to the northern region, with the total input of carbon in the future being only slightly higher than that to the southern region. 相似文献
This paper presents chemical analyses of mercury in 123 specimens of 58 meteorites. A statistical comparison is made of the mercury content in meteorites (using all available data) as a function of their composition and texture.The average mercury abundance in stony meteorites is estimated as 6.6 ppm. Stony and iron meteorites differ significantly in mercury content. Among stones, chondrites and achondrites show significant differences in the mercury content. In ordinary cbondrites, mineralogy and texture do not seem to have a significant influence on the distribution of mercury, judging from the available number of analyses. Carbonaceous chondrites, in which we found up to 500 ppm mercury, stand out among all other varieties of chondrites. Iron meteorites fall at the other extreme, having the lowest mercury concentrations (generally 0-0x ppm). In specimens of several meteorite classes, troilite is a good mercury concentrator, having a consistently higher mercury content than the meteorite as a whole. Nonetheless, troilite generally accounts for less than one-half the total mercury content of the meteorite. 相似文献
The numerical algorithm of calculation of Lyapounov coefficients (Lk) of any order is developed. The apparatus of analytical calculations is not used in this algorithm. The proposed algorithm is of use for usual computer languages and allows us to find the numerical value of Lk for any k and to make complete qualitative analyses of dynamic models on the plane. 相似文献
Rock fragments from the deepest parts of a buried hydrothermal system belonging to the Mesozoic Tethys Oceanentered as xenoliths in a Miocenic diatreme. hence b... 相似文献
The distribution function for concentrations of a scalar pollutant dispersing in the turbulent atmosphere has a finite domain that is bounded above and below. Three methods, based on extreme value statistics, are used to obtainestimates for the upper bound and to describe the high concentration tailbehaviour of the distribution; all three methods are applied to concentrationdata obtained from experimental atmospheric releases. Quantile quantile (QQ)plots are used to assess the goodness of fit of the resulting estimates of thedistribution, and also to compare the performance of the three methods. Thepredicted values for the upper bound are orders of magnitude less than thesource concentration, illustrating that molecular diffusion has a large effecton the high concentrations. 相似文献