Preparation of filter aids based on diatomites

Two major deposits of diatomaceous earth (diatomite) in the region of the Balkan Peninsula, the Kolubara basin (Serbia and Montenegro) and the Vesje deposit (Former Yugoslav Republic of Macedonia), were selected for detailed investigation of their possible application in preparation of beer filter aids. Chemical, mineralogical and structural properties of diatomite samples were analyzed with the aim of predicting the filtration efficiency. Results of beer filtering compounds preparation are presented in this paper. The parameters of crushing, drying, calcination and classification are also defined. Beer filtration tests proved diatomites to be satisfactory and not causing any degradation of filtration process or beer quality. Technological flow scheme for obtaining the beer filter aids is proposed in the paper.     

Modeled Sverdrup flow in the North Atlantic from 11 different wind stress climatologies

In studies of large-scale ocean dynamics, often quoted values of Sverdrup transport are computed using the Hellerman–Rosenstein wind stress climatology. The Sverdrup solution varies, however, depending on the wind set used. We examine the differences in the large-scale upper ocean response to different surface momentum forcing fields for the North Atlantic Ocean by comparing the different Sverdrup interior/Munk western boundary layer solutions produced by a 1/16° linear numerical ocean model forced by 11 different wind stress climatologies. Significant differences in the results underscore the importance of careful selection of a wind set for Sverdrup transport calculation and for driving nonlinear models. This high-resolution modeling approach to solving the linear wind-driven ocean circulation problem is a convenient way to discern details of the Sverdrup flow and Munk western boundary layers in areas of complicated geometry such as the Caribbean and Bahamas. In addition, the linear solutions from a large number of wind sets provide a well-understood baseline oceanic response to wind stress forcing and thus, (1) insight into the dynamics of observed circulation features, by themselves and in conjunction with nonlinear models, and (2) insight into nonlinear model sensitivity to the choice of wind-forcing product.The wind stress products are evaluated and insight into the linear dynamics of specific ocean features is obtained by examining wind stress curl patterns in relation to the corresponding high-resolution linear solutions in conjunction with observational knowledge of the ocean circulation. In the Sverdrup/Munk solutions, the Gulf Stream pathway consists of two branches. One separates from the coast at the observed separation point, but penetrates due east in an unrealistic manner. The other, which overshoots the separation point at Cape Hatteras and continues to flow northward along the continental boundary, is required to balance the Sverdrup interior transport. A similar depiction of the Gulf Stream is commonly seen in the mean flow of nonlinear, eddy-resolving basin-scale models of the North Atlantic Ocean. An O(1) change from linear dynamics is required for realistic simulation of the Gulf Stream pathway. Nine of the eleven Sverdrup solutions have a C-shaped subtropical gyre, similar to what is seen in dynamic height contours derived from observations. Three mechanisms are identified that can contribute to this pattern in the Sverdrup transport contours. Along 27°N, several wind sets drive realistic total western boundary current transport (within 10% of observed) when a 14 Sv global thermohaline contribution is added (COADS, ECMWF 10 m re-analysis and operational, Hellerman–Rosenstein and National Centers for Environmental Prediction (NCEP) surface stress re-analysis), a few drive transport that is substantially too high (ECMWF 1000 mb re-analysis and operational and Isemer–Hasse) and Fleet Numerical Meteorology and Oceanography Center (FNMOC) surface stresses give linear transport that is slightly weaker than observed. However, higher order dynamics are required to explain the partitioning of this transport between the Florida Straits and just east of the Bahamas (minimal in the linear solutions vs. 5 Sv observed east of the Bahamas). Part of the Azores Current transport is explained by Sverdrup dynamics. So are the basic path of the North Atlantic Current (NAC) and the circulation features within the Intra-Americas Sea (IAS), when a linear rendition of the northward upper ocean return flow of the global thermohaline circulation is added in the form of a Munk western boundary layer.     

Geochemical and microbiological characteristics of sediments near the Malenky mud volcano (Lake Baikal, Russia), with evidence of Archaea intermediate between the marine anaerobic methanotrophs ANME-2 and ANME-3

Detailed lithological, biogeochemical and molecular biological analyses of core sediments collected in 2002–2006 from the vicinity of the Malenky mud volcano, Lake Baikal, reveal considerable spatial variations in pore water chemical composition, with total concentrations of dissolved salts varying from 0.1 to 1.8‰. Values of methane δ¹³С in the sediments suggest a biogenic origin (δ¹³С_min. ?61.3‰, δ¹³С_max. ?72.9‰). Rates of sulphate reduction varied from 0.001 to 0.7 nmol cm^?3 day^?1, of autotrophic methanogenesis from 0.01 to 2.98 nmol CH₄ cm^?3 day^?1, and of anaerobic oxidation of methane from 0 to 12.3 nmol cm^?3 day^?1. These results indicate that methanogenic processes dominate in gas hydrate-bearing sediments of Lake Baikal. Based on clone libraries of 16S rRNA genes amplified with Bacteria- and Archaea-specific primers, investigation of microbial diversity in gas hydrate-bearing sediments revealed bacterial 16S rRNA clones classified as Deltaproteobacteria, Gammaproteobacteria, Chloroflexi and OP11. Archaeal clone sequences are related to the Crenarchaeota and Euryarchaeota. Baikal sequences of Archaea form a distinct cluster occupying an intermediate position between the marine groups ANME-2 and ANME-3 of anaerobic methanotrophs.     

Microplastics as contaminants in the marine environment: a review

Since the mass production of plastics began in the 1940s, microplastic contamination of the marine environment has been a growing problem. Here, a review of the literature has been conducted with the following objectives: (1) to summarise the properties, nomenclature and sources of microplastics; (2) to discuss the routes by which microplastics enter the marine environment; (3) to evaluate the methods by which microplastics are detected in the marine environment; (4) to assess spatial and temporal trends of microplastic abundance; and (5) to discuss the environmental impact of microplastics. Microplastics are both abundant and widespread within the marine environment, found in their highest concentrations along coastlines and within mid-ocean gyres. Ingestion of microplastics has been demonstrated in a range of marine organisms, a process which may facilitate the transfer of chemical additives or hydrophobic waterborne pollutants to biota. We conclude by highlighting key future research areas for scientists and policymakers.     

GC/MS Nontarget Analysis to Examine an Organic Groundwater Contamination. Part II: Graphical and Multivariate Methods for Searching Key Substances

GC/MS Nontarget Analysis to Examine an Organic Groundwater Contamination. Part II: Graphical and Multivariate Methods for Searching Key Substances In the nontarget analysis, a maximum of organic substances was extracted by a sequence which separates high polar, medium polar, and nonpolar compounds. This leads to the detection of 477 different organic substances in the example of the groundwater contamination investigated. To reduce the high expense for an exact identification of 477 compounds as a first step the individual compound is defined as a data set of retention time and the mass spectrum belonging to this retention time. The table of data contains now 477 individual compounds in groundwater samples collected at 10 different locations. The application of mathematical filters helps to reduce the size of the data set. Graphical methods enable large amounts of data to be visualized in a clear manner and enable to detect patterns in a data set. These patterns are the key to select typical compounds as indicator substances for the contamination source as well as the geogenic background. Similarities between the groundwater samples should not be changed by selection of the indicator compounds. Therefore, cluster analysis was applied as a controlling instrument for the final selection of the indicator compounds. The combination of graphical and multivariate data analysis is a useful tool to deduce indicator compounds for monitoring and control of complex environmental pollution states.     

The Glueckstadt Graben of the North-German Basin: new insights into the structure from 3D and 2D gravity analyses

The structure of the Glueckstadt Graben has been investigated by use of 3D gravity backstripping technique and by 2D gravity and magnetic modelling. Subtracting the gravity effects of the Meso-Cenozoic sediments together with Permian salt reveals a positive residual anomaly within the Glueckstadt Graben. This anomaly includes two local maxima over the Westholstein and Eastholstein Troughs. The 2D gravity models point to the presence of a high-density body within the lower crust of the Glueckstadt Graben. In addition, the results of 2D magnetic modelling indicate that the central part of the high-density body is overlain by an area with high susceptibility. Most probable, the formation of this high-density body is a result of complex poly-phase tectonic history of the study area. Finally, the results of gravity modelling indicate that Permian salt is not homogeneous. 3D gravity analysis and, especially, 2D gravity modelling have distinguished the differences in degree of salt saturation in salt-rich bodies, and elucidate the proportion of Rotliegend salt.     

Dynamics of the Kopački Rit (Croatia) wetland floodplain water regime

Kopa?ki Rit Nature Park is part of the Danube River natural floodplain and one of the last oases of wild life in the Danube River Basin. Due to its extraordinary value, it was inscribed on the list of Wetlands of International Importance in 1993. More than 2,000 species have been registered in this area, which consists of lakes, canals, grassland, marshland and forests. Even the number of investigations which have been performed on its biological and ecological features, hydrological and water resources characteristics, as a prerequisite for ecohydrological analyses, are still rather unknown in the scientific community. Mainly the Danube River and partly the River Drava cause flooding of Kopa?ki Rit and inundations enter the area from both the northern and southern parts. Results of hydrological and meteorological analysis show a decreasing trend of both mean and minimum, annual water levels in the Rivers Drava and Danube (respectively 1.8 and 1.38 cm/year). These reductions in water level can reduce the replenishment periods of Kopa?ki Rit Nature Park. In addition, a significant rise of mean annual air temperature and consequently water temperature (data 1988–2011) may be causing increasing evapotranspiration and loss of water within Kopa?ki Rit. But an encouraging counteracting finding is that, the results of frequency analysis show, even a discharge of 5-years’ return period on the River Danube inundates 70 % of the Danube floodplain and Kopa?ki Rit Nature Park.