Peculiarities of mercury distribution,migration, and transformation in the estuarine area of the Northern Dvina River

The mercury concentration levels in the water of aquatic ecosystem of the Northern Dvina River delta are defined. The interrelations of mercury concentrations with physicochemical parameters of the water body, namely with pH, Eh, temperature, salinity, oxygen and organic matter content are studied. The dominant forms of mercury migration and its presence in the water are revealed. Regularities of changes and spatial variability of the mercury concentrations in the estuarine area of the river, peculiarities of mercury compound migration and transformation in the barrier zone of the Northern Dvina River-Dvina Bay of the White Sea are studied.     

Bioproductivity Changes at Low and High Latitudes of the Pacific as a Response to Reorganization of Oceanic Circulation during Termination I

Oceanology - Our new and previously published data on sea surface bioproductivity changes from different parts of the Pacific Ocean in the Northern Hemisphere were analyzed in relation to...     

Response of the bering sea to Heinrich Event 11

The present paper addresses the issue of the existence of inferred hiatus on the Shirshov Ridge in the western Bering Sea, which is represented by a sand layer allegedly produced by intensification of the bottom current at the penultimate glacial/last interglacial boundary. Intensification of current velocity near the ocean floor likely provoked washout of the light fine fraction and enrichment of the sediment with heavy coarse particles. Comparison of our and published data on the western Bering Sea and North Atlantic revealed that the sand layer in sediments of the western Bering Sea at the penultimate glacial/last interglacial boundary is related to ice rafting and serves to some extent an analog of Heinrich Event 11 in the North Atlantic.     

Mercury in White Sea Bottom Sediments: Distribution,Sources, and Deposition Chronology

Oceanology - For the first time, vertical and lateral distribution patterns of mercury in White Sea bottom sediments have been determined. An abrupt change in the nature of mercury concentrations...     

Bottom sediments and their role in surface water pollution with mercury (with a special reference to the Northern Dvina River Mouth and the Dvina Bay of the White Sea)

Mercury content in bottom estuarine sediments of the Northern Dvina River and the Dvina Bay of the White Sea is studied. Major regularities of the behavior of the metal and its compounds in bottom sediments of the water area are defined. The role of lithological composition, pH and Eh of the environment, the presence of hydrogen sulfide for determining the content and forms of the mercury presence in the bottom sediments of the region are studied. The sediments related to technogenic formations are specified. The paths and forms of mercury coming from bottom sediments to the near-bottom water level are detected, and the methylmercury content in the sediments is calculated.     

Patterns of mercury distribution in bottom sediments along the Severnaya Dvina-White Sea section

This paper analyses the data on the distribution of mercury in the surface layer of bottom sediments (0–5 cm) obtained in course of sampling trips within the mouth region of the Severnaya Dvina River and the White Sea area. A total of 170 analyses for mercury were performed. Such wide-scale determination of the mercury content in the bottom sediments was carried out for the first time in the study region. The patterns of mercury distribution in the Severnaya Dvina River-White Sea transect are revealed and described. It is shown that the marginal filter of the Severnaya Dvina River facilitates cosedimentation of the main portion of anthropogenic mercury with suspended matter. This drastically decreases the risk of penetration of mercury to the White Sea waters and partially (with the gravity current) to the Barents Sea waters. In general, the Severnaya Dvina River is characterized by mercury pollution of a local scale within the urban territories. No regional pollution of the White Sea off the marginal filter was revealed.     

Paleoceanographic conditions in the western Bering Sea as a response to global sea level changes and remote climatic signals during the last 180 kyr

We present results from the sediment core SO201-2-85KL retrieved from the western Bering Sea that recovered the past 180 000 years. For the first time, the intense dissolution of calcareous microfossils has been established when the Bering Strait was open during the glacioeustatic sea level rise. Possible mechanisms of climatic teleconnections between remote regions are considered.