Benthic Nutrient Recycling in Port Phillip Bay, Australia

Benthic chamber measurements of the reactants and products involved with biogenic matter remineralization (oxygen, ammonium, nitrate, nitrite, phosphate, silicate, TCO₂and alkalinity) were used to define solute exchange rates between the sediment and overlying water column of Port Phillip Bay, Australia. Measurements at various sites throughout the bay, conducted during the summers of 1994 and 1995, indicate that the variability in flux values within a site is comparable to year-to-year variability (±50%). Four regions of the bay were distinguished by sediment properties and the northern region was identified as having 3–30 times greater nutrient regeneration rates than the other regions. Benthic recycling accounted for 63 and 72% of the annualized N and P input, respectively, to the entire bay as determined by summing benthic, dissolved riverine, atmospheric and dissolved effluent sources. However, bay-wide sedimentary denitrification accounted for a loss of 63% of the potentially recyclable N. This fraction is higher than many other coastal regions with comparable carbon loading. Denitrification efficiency is apparently not enhanced by benthic productivity nor by bio-irrigation. The rate of bio-irrigation is negatively correlated with denitrification efficiency. Bio-irrigation was studied using radon-222 and CsCl spike injection chamber measurements. Radon fluxes from sediments in Port Phillip Bay were enhanced over the diffusive flux by 3–16 times. The modelled rate of loss of Cs from chamber water was positively correlated with radon flux enhancement results. Both methods identify regions within Port Phillip Bay that have particularly high rates of non-diffusive pore-water overlying water solute exchange.     

Treatment of Hydrodynamic Loading for Random Sea State

- In order to employ cost effective frequency domain analysis for off-shore structures treatment of hydrodynamic loading is essential. Drag and inertia dominated, resonating and antiresonating cases under random sea states are analyzed to highlight the implications and relative merits of four salient linearization techniques.     

Metallothionein-like proteins induced by cadmium stress in the scallop Mizuhopecten yessoensis

Organisms have evolved a cellular response called stress protein response that increases their tolerance in adverse environmental conditions. Well known stress proteins that bind essential and toxic metals are metallothionein (MT). The scallop Mizuhopecten yessoensis is the most interesting organism because it is able to accumulate toxic cadmium in its digestive gland. However, in the tissue of the digestive gland of Mizuhopecten yessoensis MT (metallothioneins) have not been found. Eastern scallops, Mizuhopecten yessoensis, were collected from two locations ?? one clean and one polluted site. The concentrations of cadmium (Cd), copper (Cu) and zinc (Zn) were measured in the digestive gland. There was a significant increase in Cd concentrations in this studied tissue. We found that in the presence of cadmium Mizuhopecten yessoensis can induce high molecular proteins. The results of experiments have shown that Cd-binding ligands have a number of properties similar to MT: acetone and temperature stability; the ability to bind some metals, including Cd, Cu and Zn. Protein chromatography (FPLC, Superosa 12) from the digestive gland of scallop M. yessoensis has shown that cadmium is associated with high molecular weight Cd-binding proteins (72 kDa and 43 kDa). The major cadmium-binding protein 72 kDa is glycoprotein. In experiments we have demonstrated that Cd-binding proteins can be induced when there is cadmium exposure. The results of this study strongly suggest that the far eastern scallop Mizuhopecten yessoensis has a unique and well-developed system for the detoxification of heavy metals and it allows for biochemical systems to be maintained in a relatively stable manner in the presence of heavy metals.     

Change in biochemical and morphological characteristics of Lonicera caerulea in tectonically active zone of the Dzhazator River Valley (Altai Mountains)

Local geophysical and geochemical anomalies affect the polymorphism of taste variations, berry shape, and content of some biologically active substances in Lonicera caerulea leaves in the tectonically active Altai Mountains (Dzhazator River basin).     

Studies of the European Arctic on Cruise 80 of the R/V Akademik Mstislav Keldysh

Oceanology - The multidisciplinary expedition “European Arctic-2020” on board the R/V Akademik Mstislav Keldysh took place from July 31 to August 26, 2020. The investigations were...     

Caspian Sea Level Fluctuations in the Neopleistocene (Was There an Atelian Regression?)

The article deals with deposits exposed in sections along the rivers of the Caspian lowland and on the eastern slope of the Ergenei. The conclusion is made about the lagoonal origin of chocolate clays lying on high-capacity subaerial and alluvial–deltaic deposits. The impact of the Caspian Sea level rise on coastal processes is examined. Taking into account the regularities in the behavior of the coastal zone during sea level rise, subaerial deposits with such thickness in the outcrops could not have been preserved during the early Khvalynian transgression from –100 m. Another curve of Caspian Sea level fluctuations is proposed, where there is no deep Atelian regression between the Khazarian and Khvalynian transgressions. It is concluded that the Khazarian transgression was one of the largest in the history of the Caspian Sea. Its level was slightly less than that of the Khvalynian transgression. The rise of the level of the latter began not from –100 m, but from about 5–15 m; i.e., this transgression was in fact an oscillation of the Caspian Sea against its gradual regression after the Khazarian transgression. Sea level oscillations contributed to the formation of lagoonal-transgressive terraces, in which chocolate clays accumulated.

     

Two Modes of Atmosphere–Ocean Interaction in the Atlantic Sector of the Arctic Basin

Oceanology - The paper examines the influence of the main mode of interannual variability of the North Atlantic climate system—the North Atlantic Oscillation (NAO)—on the hydrophysical...     

Role of the Radiation Factor in Global Climatic Events of the Late Holocene

Izvestiya, Atmospheric and Oceanic Physics - On the basis of calculations of insolation and insolation characteristics, taking into account changes in solar activity, the causes of global climatic...     

Experience of Studying the Turbulent Structure of the Atmospheric Boundary Layer Using an Unmanned Aerial Vehicle

Izvestiya, Atmospheric and Oceanic Physics - The growing relevance of the use of unmanned aerial vehicles (UAVs) for studying turbulence in the atmospheric boundary layer (ABL) is associated with...     

Comparative Analysis of Arctic Sea Ice Area Derived from Satellite Microwave Radiometry Data (VASIA2 Algorithm) with Ice Charts of the Arctic and Antarctic Research Institute

Izvestiya, Atmospheric and Oceanic Physics - The Arctic Sea ice area, calculated by the VASIA2 algorithm using the SSMIS data during the most intensive melting of the ice cover in 2019, is compared...