Isotopic Composition of Carbon in Humus Acids of Albic Retisols and Luvic Chernozems

Eurasian Soil Science - Carbon isotope ratios in soil organic matter are often used in paleoecological research for reconstructing climate and plant communities (type of photosynthesis). The...     

Major Australian-Antarctic plate reorganization at Hawaiian-Emperor bend time

A marked bend in the Hawaiian-Emperor seamount chain supposedly resulted from a recent major reorganization of the plate-mantle system there 50 million years ago. Although alternative mantle-driven and plate-shifting hypotheses have been proposed, no contemporaneous circum-Pacific plate events have been identified. We report reconstructions for Australia and Antarctica that reveal a major plate reorganization between 50 and 53 million years ago. Revised Pacific Ocean sea-floor reconstructions suggest that subduction of the Pacific-Izanagi spreading ridge and subsequent Marianas/Tonga-Kermadec subduction initiation may have been the ultimate causes of these events. Thus, these plate reconstructions solve long-standing continental fit problems and improve constraints on the motion between East and West Antarctica and global plate circuit closure.     

Evaluation of genetic diversity of reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>) by means of multilocus DNA fingerprinting

The parameters of intragroup and intergroup genetic similarity coefficients, genetic distances, and DNA marker fragments of reindeer of the wild type and Nentsi and Evenk breeds inhabiting various regions of Krasnoyarsk krai are obtained by the DNA fingerprinting method. Noticeable divergence of reindeer of the wild type and Evenk breed is found.     

The relationship between Adirondack lake pH and levels of mercury in yellow perch

Levels of total mercury in yellow perch Perca flavescens from Adirondack lakes were studied in relation to characteristics of the lakes to determine why some lakes had fish with higher concentrations of mercury. Almost all mercury in fish is in the form of methylmercury, which can pose significant health hazards to humans who consume such fish. Fish mercury concentrations and water chemistry data were analyzed from eight Adirondack lakes. Four lakes (Halfmoon Lake, Sand Pond, Rock Pond, and Upper Sister Lake) had pH values of less than 5.0. Four other lakes (Lake Adirondack, Kings Flow, Harris Lake, and Lake Kushaqua) had pH values of more than 7.0. The acidic lakes also had high levels of aluminum and low acid-neutralizing capacity relative to the neutral lakes. Yellow perch (n = 100) from the acidic lakes had significantly higher levels of mercury than did those (n = 102) from the neutral lakes (P < 0.001), and the total mercury concentration increased with both length and weight of the fish. We conclude that the pH of the lake water is a major factor in determining the concentration of methylmercury in yellow perch.     

New sources of compact spike morphology determined by the genes on chromosome 5A in hexaploid wheat

Little is known about the relationship between compact spike loci in hexaploid wheat species. We studied two new compact spike mutants of common wheat Triticum aestivum L. (2n?=?6x?=?42, genome formula BBAADD). The new compact spike genes, C ⁷³⁹ of MCK 739 and Cp of near-isogenic line Mironovskaya 808 (Vrn1), were mapped using aneuploid stocks and microsatellite markers. The C ⁷³⁹ and Cp loci were distally linked with the microsatellite marker Xbarc319 in the F₂ populations of MCK 739?×?‘Novosibirskaya 67’ and Cp-Mironovskaya 808 (Vrn1)?×?‘Saratovskaya 29’. It was evident that the loci affecting compact spikes in T. aestivum mutants were located on chromosome 5AL distal from Q locus. These loci also affected to semi-dwarfism. We named this locus Cp1 (C ompact p lant 1) for all accessions. Cp1 was allelic to C ¹⁷⁶⁴⁸ gene located on the chromosome 5AL of tetraploid wheat [Triticum durum Desf. (2n?=?4x?=?28, genome formula BBAA)]. These dominant genes on chromosome 5AL will be utilized as new gene resources of compact spike morphology in hexaploid wheat. Relationship between loci Q and Cp1 was also discussed.     

Dependence of the aggregate swelling parameters in soddy-podzolic soils on their properties

The degree and rate of the aggregate swelling in loamy sandy, loamy, and clayey soddy-podzolic soils of northwestern Russia have been measured using the methods of image analysis. The results of the study have shown that the degree of swelling of the soil aggregates depended on the proportions of the fine (0.005 mm) and sandy fractions, and the rate of the swelling depended on the density of the soil solid phase. A reliable effect of the soil organic matter content on the swelling rate of the studied objects has been established. The aggregates of the arable soddy-podzolic soils with the highest content of organic matter, as well as the aggregates of the native soils, have been characterized by the lowest swelling rates. A method has been developed for the determination of the swelling rate of soil aggregates that has enabled the assessment of the soil structure. The regression dependences of the degree and rate of the aggregate swelling on the properties and composition of soddy-podzolic soils have been plotted.     

In situ observations of a high-pressure phase of H2O Ice

A previously unknown solid phase of H2O has been identified by its peculiar growth patterns, distinct pressure-temperature melting relations, and vibrational Raman spectra. Morphologies of ice crystals and their pressure-temperature melting relations were directly observed in a hydrothermal diamond-anvil cell for H2O bulk densities between 1203 and 1257 kilograms per cubic meter at temperatures between -10 degrees and 50 degreesC. Under these conditions, four different ice forms were observed to melt: two stable phases, ice V and ice VI, and two metastable phases, ice IV and the new ice phase. The Raman spectra and crystal morphology are consistent with a disordered anisotropic structure with some similarities to ice VI.