The phenomenon of bloom development of the invasive potentially toxic dinoflagellate <Emphasis Type="Italic">Gonyaulax polygramma</Emphasis> in deep water areas of the Caspian Sea

This work presents the first data on the occurrence of the invasive, potentially toxic dinoflagellate Gonyaulax polygramma in the composition of plankton phytocenoses in the Caspian Sea. It was revealed that G. polygramma plays the key role in the quantitative characteristics of summer plankton phytocenoses and its bloom during the summer seasons of 2010 and 2013 was comparable in biomass (15–16 g/m³) to a “red tide.” In addition, the correlation between the G. polygramma bloom and the wind upwelling system in the eastern mid-Caspian region was established. For the first time, it is suggested that “bloom” of G. polygramma can also occur in deep-water halistatic areas (Derbent depression), remote from the upwelling system.     

Concentration,Composition, and Fluxes of Dispersed Sedimentary Material in the Snow and Ice Cover of the Polar Arctic

Oceanology - Abstract—Dispersed sedimentary material in the snow and ice cover is directly determined near the North Pole. The composition of sedimentary material in the snow and ice cover...     

Oxygen isotope and deuterium composition of snow cover on the profile of Western Siberia from Tomsk to the Gulf of Ob

The purpose of this work is to study the variability of the isotope composition (δ¹⁸О, δD, d _exc) of the snow cover on a long transect of Western Siberia from the southern taiga to the tundra. The study of the snow cover is of paleogeographic, paleogeocryological, and paleohydrological value. The snow cover of western Siberia was sampled on a broadly NS transzonal profile from the environs of Tomsk (southern taiga zone) to the eastern coast of the Gulf of Ob (tundra zone) from February 19 to March 4, 2014. Snow samples were collected at 31 sites. Most of the samples represented by fresh snow, i.e., snow that had fallen a day before the moment of sampling were collected in two areas. In the area of Yamburg, the snow specimens collected from the surface are most probably settled snow of different ages. The values of δ¹⁸О in the snow from Tomsk to Yamburg varied from–21.89 to–32.82‰, and the values of δD, from–163.3 to–261.2‰. The value of deuterium excess was in the range of 4.06–19.53‰.     

Spatial variability of different compounds in water,suspension, and sediments of the Volga River

Doklady Earth Sciences -     

The MSL-110 small sediment trap

A simple construction of the MSL-110 sediment trap developed at the Laboratory of Physical-Geological Research of the Shirshov Institute of Oceanology, Russian Academy of Sciences, is presented. The trap is easily assembled from standard parts available at stores. The trap is easy to use, reliable, and inexpensive. It is applied for determination of sedimentary matter fluxes and their components in water columns of seas, lakes, and other water reservoirs.     

Vertical flux of phytoplankton and particulate matter in the White Sea according to the long-term exposure of sediment traps

The vertical fluxes of phytoplankton (VF_Phyto) and particulate organic carbon (VF_POC) in the White Sea were determined using seven long-term (292 to 296 days) sediment traps moored at five stations at 67–255 m depths. The annual VF_Phyto and VF_POC ranged from 0.55 to 24.64 g C/m² and from 3.7 to 93.9 g C/m², respectively. The highest VFPhyto was observed in the Basin region located close to the Gorlo along the Tersk coast. The algal biomass accounted for 15–43% of the VF_POC. Diatoms comprised the most important group, accounting for 83–100% in the sedimented biomass. Thalassiosira nordenskioeldii dominated in the VF_Phyto at all the stations except for the station in the basin close to Onega Bay, where Ditylum brightwellii was the most abundant.     

Occurrence forms of trace metals in recent bottom sediments from the White and Barents Seas

For the first time based on determination of the geochemical occurrence forms of trace metals the main processes that control the accumulation of elements (Al, Mn, Fe, Mo, Cr, Ni, Co, Cu, Pb, Cd, and As) in the recent sediment cores from the White Sea and Barents Sea were quantified. A high-resolution study of the bottom sediment cores allowed us to estimate the short-term variations (periodicity of 10–15 years) in the accumulation of metals to reveal the periods of maximum Fe and Mn contents in the amorphous hydroxides fraction, which serve as effective adsorbents of the trace elements majority, including heavy metals. The Mn/Fe ratio in the amorphous hydroxides phase can be considered as geochemical indicators of early diagenesis.     

New data on the Holocene evolution of the Dvina Bay (White Sea)

Doklady Earth Sciences - The Holocene sediments from the inner part of the Dvina Bay of the White Sea (core no. 6042) were analyzed with multidisciplinary methods for the first time. The age of the...