First evidence of altered vitellogenin-like protein levels in clam Tapes philippinarum and in cockle Cerastoderma glaucum from the Lagoon of Venice

Possible xenoestrogenic effects were investigated, for the first time, in two bivalve species from the Lagoon of Venice (Italy): the clam Tapes philippinarum and the cockle Cerastoderma glaucum. Bivalves were collected far from their reproductive phase at the very early stage of gametogenesis (January), and in the pre-spawning period (June) in six sites. Vitellogenin (Vg)-like proteins (a biomarker of exposure to estrogenic compounds) were measured by the alkali-labile phosphate method (ALP), in both haemolymph and digestive gland from males and females (when it was possible to distinguish sex by microscopic observation of gonadal tissue). Haemolymph calcium concentrations (a parameter considered closely related to the presence of Vg-like proteins) and the bivalve condition index (CI) were also measured. In both seasons, bivalves collected at Campalto (near a sewage treatment plant) and Marghera (a highly contaminated area) had higher Vg-like protein levels, particularly in haemolymph, than animals from the other sampling sites. Interestingly, CI had high values in these polluted sites. In June only, Vg-like proteins and Ca²⁺ levels in haemolymph exhibited similar trends in both bivalve species at most sampling sites. The responsiveness of bivalves to environmental xenoestrogens was higher in June, allowing better discrimination among sites. The present study demonstrates that animals from highly polluted areas have increased Vg-like protein levels. As endocrine disruption due to exposure to estrogenic compounds may cause fertility reduction, alterations in the sex ratio, and a decrease in reproductive rate, a condition of potential risk for bivalve populations in estuarine areas is highlighted.     

Seasonal variability of the equatorial undercurrent termination and associated salinity maximum in the Gulf of Guinea

The termination of the Equatorial Undercurrent (EUC) in the eastern equatorial Atlantic during boreal summer and fall, and the fate of the associated saline water masses, are analyzed from in situ hydrological and currents data collected during 19 hydrographic cruises between 2000 and 2007, complemented by observations from Argo profiling floats and PIRATA moorings, and from a numerical simulation of the Tropical Atlantic Ocean for the period 1993–2007. An intense variability of the circulation and hydrological properties is evidenced from observations in the upper thermocline (24.5–26.2 isopycnal layer) between June and November. During early boreal summer, saline water masses are transported eastward in the upper thermocline to the African coast within the EUC, and recirculate westward on both sides of the EUC. In mid-boreal summer, the EUC weakens in the upper thermocline and the equatorial salinity maximum disappears due to intense mixing with the surface waters during the upwelling season. The extra-equatorial salinity maxima are also partially eroded during the boreal summer, with a slight poleward migration of the southern hemisphere maximum until late boreal summer. The upper EUC reappears in September, feeding again the eastern equatorial Atlantic with saline waters until boreal spring. During December–January, numerical results suggest a second seasonal weakening of the EUC in the Gulf of Guinea, with a partial erosion of the associated equatorial salinity maximum.     

Structural and chemical heterogeneity of natural crystals and microgeochemical line of research in ontogeny of minerals

A review of the current state of genetic mineralogy in the field of the chemical heterogeneity of mineral individuals is presented. Due to advances in the local analysis of matter, the ontogenetic approach is now being focused on the chemical anatomy of minerals. A new line of research, microgeochemistry, deals with the migration of chemical elements in natural crystals caused by defects in the crystal lattice. It becomes evident that structural and chemical heterogeneity is an intrinsic property of mineral individuals. Phenomenological laws of this heterogeneity and the interaction of atoms with lattice defects are stated.     

Tungsten accessory minerals in lithium-fluoric granites of the Russian Far East

By means of the technique of local analysis, the presence of a wide variety of tungsten and tungsten-containing accessories was first revealed in the composition of lithium-fluoric granites of the Far East, which represents a substantial similarity and regional peculiarity of these rocks. It was concluded that the tungsten accessory mineralization might be considered as an indication of the genetic relationship of the mineralization of the East Asian tin-tungsten zone to the Pacific rare-metal granites.     

Ocean wave attenuation due to soft seafloor sediments

Abstract

Ocean waves traveling over soft bottoms attenuate as a result of energy being absorbed by the soft bottom. This wave attenuation is important in the design of offshore facilities. The magnitude of wave attenuation can be predicted with an analytical model that couples wave and seabottom motions and realistically models the nonlinear stress‐strain behavior of soft sediments. An extensive parameter study was performed to develop wave attenuation behavior. Soil and wave characteristics typical of the Mississippi Delta were used for these analysis. Predicted results are compared with field observations, and good agreement is found.     

Hydrogen and Carbon Groups in the Structures of Rock-Forming Minerals of Rocks of the Lithospheric Mantle: FTIR and STA + QMS Data

Using IR–Fourier spectrometry (FTIR) and simultaneous thermal analysis combined with quadrupole mass spectrometry of thermal decomposition products (STA + QMS), olivines and clinopyroxene from xenolites of spinel and garnet lherzolites contained in kimberlites and alkaline basalts were studied to confirm the occurrence of hydrogen and carbon within the structure of the minerals, as well as to specify the forms of H and C. The presence of hydroxyl ions (OH–) and molecules of crystal hydrate water (H₂Ocryst) along with CO₂, CH, CH₂, and CH₃ groups was detected, which remained within the structures of mantle minerals up to 1300°C (by the data of both techniques). The total water (OH–and H2Ocryst) was the prevailing component of the C–O–H system.