scholarly journals The influence of fluids on the species composition and preservation of microfossils in biogenic carbonate sediments by hydrothermal cluster “Pobeda” (Mid-Atlantic ridge)

Author(s):  
I. F. Gablina ◽  
O. B. Dmitrenko ◽  
T. A. Khusid ◽  
N. V. Libina

The species composition, distribution and preservation of carbonate shells of nanno and microfossils of biogenic bottom sediments within the hydrothermal cluster Pobeda (1707.451708.7 n) were studied on the basis of materials obtained in flight No. 37 of NIS Professor Logachev in the Russian exploration area (Mid-Atlantic ridge). Physical-chemical parameters and the total carbonate content of sediments were measured, their changes in column sections were revealed. For complexes of coccoliths studied precipitation is attributed to the top (acme) biostratigraphic zone of Emiliania huxleyi. It is established that within the zone of hydrothermal activity (ore cluster Pobeda) the total number of microorganisms decreases and their species diversity decreases, as a rule, in the lower part of the columns. Down the column section also decreases the Eh, pH and carbonate precipitation. These changes are explained by the influence of diffuse hydrothermal fluids.

2020 ◽  
Author(s):  
◽  
Julija Pauraitė-Dudek

The impact of submicron aerosol source and physical-chemical parameters on atmospheric radiative balance


1995 ◽  
Vol 31 (7) ◽  
pp. 311-320 ◽  
Author(s):  
R. M. Ashley ◽  
W. Dabrowski

Combined sewage coliform bacteria are important as indicators of pathogenic microorganisms and of their possible discharge into the environment. Whilst specifying limits for viruses, most legislation recognises the difficulty of enumerating such organisms and also prescribes limits for coliforms. Despite the importance of these organisms, little is known about their numbers and behaviour in sewerage systems. A data collection programme is described which has monitored dry and wet weather sewage coliform bacteria and also sediment bacteria. These data are used to review recent UK recommendations for assessing bacteria numbers in storm discharges. It is concluded that relationships between bacteria numbers and other physical/chemical parameters may be developed during DWF, but are seasonally and catchment dependent. Extension of DWF measurements to predict storm bacteria may be possible with more data.


1999 ◽  
Vol 40 (3) ◽  
pp. 57-65 ◽  
Author(s):  
Martin M. Karpiscak ◽  
Robert J. Freitas ◽  
Charles P. Gerba ◽  
Luis R. Sanchez ◽  
Eylon Shamir

An integrated wastewater treatment facility, consisting of upper (solids separators, anaerobic lagoons, and aerobic ponds) and lower (wetland cells) subsystems, has been built to replace the lagoon at a dairy in Arizona, USA. The collection sump of the new waste treatment facility collects all dairy wastewater outflow. Wastewater is then pumped to solids separators, and flows by gravity to anaerobic ponds and aerobic ponds. The upper subsystem is expected to treat the water sufficiently so that the wetland cells may achieve further pollutant reductions. The lower subsystem, comprised of 8 surface wetland cells with an approximate surface area of 5,000 m2, receives outflow from the ponds. The cells are planted with cattail (Typha domingensis), soft-stem bulrush (Scirpus validus), and reed (Phragmites australis). After treatment is completed via the lagoons and ponds followed by the wetland cells, the wastewater can be reused to flush barns or to irrigate crops. Performance of the overall system is evaluated by measuring physical, chemical and biological parameters in water samples taken from selected locations along the treatment system. Chemical parameters studied include biochemical oxygen demand, pH, total suspended solids, nitrogen species. Biological monitoring included coliforms (total and fecal) and Listeria monocytogenes.


2021 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
Liudmila Demina ◽  
Irina Gablina ◽  
Olga Dara ◽  
Dmitry Budko ◽  
Nina Gorkova ◽  
...  

We examined the distribution of Fe, Mn, Cu, Zn, and Pb in one core of metalliferous, and one core of non-mineralized (background) carbonate sediments (located 69 km northwards), from the Pobeda hydrothermal field. Mechanisms of metal accumulation in sediments (12 samples) were evaluated based on sequential extraction of geochemical fractions, including mobile (exchangeable complex, authigenic Fe-Mn hydroxides, and sulfides), and lithogenic (fixed in crystalline lattices) forms. Maps of element distribution in sediment components were obtained using a scanning electron microscope equipped with an energy-dispersive spectrometry detector. In metalliferous sediments, according to X-ray diffraction data, the main Fe mineral phase was goethite FeOOH (37–44% on a carbonate-free basis). The contents of Fe and Mn reached 31.6 and 0.18%, respectively, whereas concentrations of Cu, Zn and Pb were 0.98, 0.36, and 0.059%. The coefficient of metal enrichment relative to background values varied from 16 to 125 times. The exception was Mn, for which no increased accumulation was recorded. Essential mass of Fe (up to 70% of total content) was represented by the residual fraction composed of crystallized goethite, aluminosilicates, the minerals derived from bedrock destruction processes. Among geochemically mobile fractions, 90–97% of total Fe was found in the form of authigenic oxyhydroxides. The same fraction was the predominant host for Mn in both metalliferous and background sediments (55–85%). A total of 40–96 % of Cd, Cu, Zn, and Pb were associated with these Fe and Mn fractions. The sulfide fraction amounted to roughly 10% of each metal. In metalliferous sediment core, the maximum concentrations of metals and their geochemically mobile fractions were recorded in deeper core intercepts, an observation that might be attributed to influence of hydrothermal diffused fluids. Our data suggested that metals are mostly accumulated in carbonate sediments in their contact zone with the underlying serpentinized basalts.


2009 ◽  
Vol 266 (1-4) ◽  
pp. 52-64 ◽  
Author(s):  
K.M. Haase ◽  
A. Koschinsky ◽  
S. Petersen ◽  
C.W. Devey ◽  
C. German ◽  
...  

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