Reduction of the Trophic Status of a Water Body with the Use of Large-Size Zooplankton

It is shown that large-size zooplankton can be used as a natural filter in flow-through plants for reducing the trophic status of water bodies and improve water transparency. Experiments in Chistye Prudy pond in the period of blue-green algae blooming show large-size zooplankton to reduce phytoplankton biomass in the pond throughout the period of phytoplankton growth. Daphnia magna specimens (with a biomass of 92 to 3450 mg/l) in lothic ecosystems are found to reduce the biomass of dominating Anabaena spirodes blue-green algae when this biomass attains its maximum.     

Micromorphology of solonetzic horizons as related to environmental events in the Caspian Lowland

Micromorphology of solonetz species with special attention to natric horizon was studied in microcatenas at the Dzhanybek Research Station （northwestern Caspian Lowland）. The solonetzic （natric） horizon is easily identified, and it occurs at varying depths, which are the criteria for subdividing solonetzes into 4 species, namely, crusty, shallow, medium and deep. In this sequence, the depth of humus-accumulative horizons increases, and the upper boundary of salinity manifestations goes down. The following micromorphological features are assumed as typical for natric horizons： angular blocky microstructures with partially accommodated aggregates having sharp boundaries and narrow plane-like packing voids; b-fabric speckled in the aggregates＇ centers and monostriated at their peripheries merging into stress coatings; very few interpedal voids; organo-clay coatings; humus- enriched infillings; no calcite and gypsum pedofeatures. A complete set of ＂natric＂ features was found only in the crusty solonetz; the shallow solonetz lacks only illuviation coatings, while the medium and deep species have several modifications of fabric elements： blocky aggregates have a rounded shape and are penetrated by biogenic channels favoring their further biogenic reworking; plant residues became more abundant and diverse, and blackened tissues occur; illuviation clay coatings evolved into papules; stress coatings gave birth to striated bfabrics, thus maintaining a high plasma orientation. The thin sections of natric horizons made 50 and 20 years ago were examined to study the influence of environmental changes （increase in precipitation and rise of ground water table） on micropedofeatures. The following processes took place： （i） in the topsoil： humus accumulation and biogenic structurization; （ii） in the natric horizon - re-arrangement of clay coatings into micromass b-fabrics; and （iii） in the lower part of the natric horizon - development of pseudosand fabric, calcite and gypsum formation. The trends revealed are in good agreement with the environmental events.     

Dynamics of suspended matter concentration in Chupa Inlet (Karelian Coast,the White Sea) in summer and autumn

Studies on the water and suspended matter concentration dynamics were performed for the summer and autumn periods in Kruglaya Bay, Chupa Inlet (Karelian Coast, the White Sea). The tidal cycle appeared as the major factor defining the water salinity, temperature, and suspended matter concentration. The water temperature and suspended matter concentration increased during low tide, and the opposite pattern was observed for water salinity; all the processes were true for both surface and bottom water layers. Therefore, we conclude that major bulk of the allochtonous suspended matter is carried into the sea by the ebb stream.     

A multi-proxy approach for revealing recent climatic changes in the Russian Altai

For the first time we present a multi-proxy data set for the Russian Altai, consisting of Siberian larch tree-ring width (TRW), latewood density (MXD), δ¹³C and δ¹⁸O in cellulose chronologies obtained for the period 1779–2007 and cell wall thickness (CWT) for 1900–2008. All of these parameters agree well between each other in the high-frequency variability, while the low-frequency climate information shows systematic differences. The correlation analysis with temperature and precipitation data from the closest weather station and gridded data revealed that annual TRW, MXD, CWT, and δ¹³C data contain a strong summer temperature signal, while δ¹⁸O in cellulose represents a mixed summer and winter temperature and precipitation signal. The temperature and precipitation reconstructions from the Belukha ice core and Teletskoe lake sediments were used to investigate the correspondence of different independent proxies. Low frequency patterns in TRW and δ¹³C chronologies are consistent with temperature reconstructions from nearby Belukha ice core and Teletskoe lake sediments showing a pronounced warming trend in the last century. Their combination could be used for the regional temperature reconstruction. The long-term δ¹⁸O trend agrees with the precipitation reconstruction from the Teletskoe lake sediment indicating more humid conditions during the twentieth century. Therefore, these two proxies could be combined for the precipitation reconstruction.     

Boron in magnesium minerals of the humite group

Based on microprobe analysis and IR-spectroscopy of a representative collection of magnesium minerals of the humite group (282 samples from 80 various geological-genetic occurrences all over the world), it was shown for the first time that these minerals typically concentrate trace boron (from 0.5 to 4.9 wt % B₂O₃ in 63 samples). The diagnostic bands of B-O stretching vibrations in IF-spectra of magnesium minerals of the humite group occur within the 1170–1190, 1262–1289, and 1306–1331 cm^?1 ranges and are regularly shifted to the low frequencies in a norbergite-chondrodite-humite-clinohumite series. Boron isomorphically replaces silicon in tetrahedra, probably, by Pertsev’s scheme: Si⁴⁺ + O^2? → B³⁺ + (F,OH)^?.     

Constructing the tree-ring chronology and reconstructing summertime air temperatures in southern Altai for the last 1500 years

We have constructed and analyzed the 1896-year-long tree-ring chronology for the territory of the Altai Republic. The chronology was based on wood of live trees and remains of trunks of Siberian larch (Larix sibirica Ledeb.) from the upper timberline (2300 m) of the Dzhelo river valley. The chronology agrees well with palaeoclimatic data and reflects the main climatic changes in the northern hemisphere for the last two millennia: an extraordinary decrease in increment after the year 536, ??mean secular warming??, the ??Little Ice Age??, and current warming. By calculating the response function between the tree-ring chronology for the Dzhelo and data from weather stations, it was possible to reconstruct the series of June?CJuly air temperature variability for the last 1500 years. The chronology can be used in dating archaeological wood, i.e. in determining the calendar time at which archaeological monuments were constructed.     

Anisotropy of high-energy cosmic rays

The anisotropy of high-energy (∼10 GeV and above) cosmic rays is investigated. A simplified model of the heliosphere constructed as a basis for the theory of their long-period variations is investigated for applicability to describing the cosmic-ray anisotropy. This model has been found to need a modification. The necessary changes of the model do not affect the conclusions on the 22-year variations reached on its basis but make it possible to construct a theory of cosmic-ray anisotropy. The theoretical results on the anisotropy are compared with its long-term observations in a wide energy range performed in Yakutsk.     

Coarse fragmental material of the littoral zones on the Murmansk and Carelian coasts

A three-year study of the abrasion of coarse fragmental material on the Murmansk coast has been carried out. According to the researchers, the average rate of the abrasion of the coarse-fragmental material of granitoid composition on the Murmansk coast has been determined. It was revealed that the rate of the destruction of the blocks increases from the lower littoral zone to the upper one. The estimation of the quantity of sedimentary material coming to the sedimentation basin as a result of the abrasion of coarse-fragmental material has been carried out.     

The Role of Filtering Zooplankton in De-Eutrophication of Water Bodies

The filtration capacity of large-size cladoceras is examined. Cladoceras Simocephalus vetulus with a biomass of 1.6 g/l in flow-through ecosystems isolated from ichthyifauna can reduce phytoplankton biomass from 2.89 to 0.12 mg/l within 1 h. Particularly, the biomass of blue-green algae Anabaena spiroides decreases from 0.14 to 0.01 mg/l, and their filaments shorten. In the period when phytoplankton biomass in the water body was at maximum, the activity of cladoceras (biomass of 2.1 g/l) resulted in a decrease in this biomass in flow-through ecosystems by a factor of 13.6 (down to 0.34 mg/l). The decrease in phytoplankton biomass in flow-through ecosystems facilitated changes in its composition in the water body (an increase in the share of green algae) and was accompanied by an increase in water transparency.__________Translated from Vodnye Resursy, Vol. 32, No. 3, 2005, pp. 371–379.Original Russian Text Copyright © 2005 by Pogozhev, Gerasimova.