Coastal water pollution in two rivers of the Bengal delta

A thorough comprehension of relevant environmental parameters is a prerequisite to preventing coastal degradation and environmental balance in coastal zones. In this study, we correlate major physicochemical of two coastal rivers (Matla and Saptamukhi) in the Sunderban district, West Bengal. The parameters namely: pH, salinity, dissolved oxygen, suspended solids, nitrogen and phosphorus concentrations (inorganic and total) of these two rivers were studied in detail over the 90s decade. We hypothesized that both natural and anthropogenic activities during that time have contributed to the pollution and employed the above parameters to test our hypothesis. Our results reveal that the quality of waters in the rivers have been showed to be dependent on flood impacts, storm surge, eutrophication, domestic sewage, agricultural and industrial wastes. Thus, both natural and anthropogenic causes are the behind coastal pollution of river waters. We conclude that they have all contributed to pollution of these rivers in various ways and we calculate the differential effects of these parameters on coastal pollution.     

The Lower Jurassic of the Eastern Caspian region and the Middle Caspian Basin: Lithology,facies, taphonomy

Lithofacies of the productive Upper Triassic-Lower Jurassic deposits of the Eastern Caspian region, studied in wells on the Caspian coast and exposed in the outcrops of the Mountainous Mangyshlak, are described and analyzed. The similarity of the structure of the Mesozoic sedimentary beds of the Middle Caspian Basin and of those of the land adjacent to its eastern coast is confirmed. Comparative analysis of lithofacies allowed the reconstruction of the paleogeographic setting and depositional environments in the studied region during the Early Jurassic. A unique fossil plant occurrence is discovered in the upper part of the Lower Jurassic series (in the lower subformation of the Kokala Formation; Eastern Caspian region). Fossil plant taphonomy and the lithology of host rocks in the occurrence resulted from unusual paleogeographic settings that existed in the Middle Caspian Basin at the time of the Early-Middle Jurassic boundary.     

3-D GRACE gravity model for the 2011 Japan earthquake

The GRACE mission has contributed to the seismic characterization of major earthquakes in offshore regions of the world. Here, we isolate satellite gravity signal (μGal range) for the Japan Earthquake of 2011 using a difference method. Contrary to the existing gravity models, we propose a unit vertical pyramid based five-layer 3-D thrust fault model, which extends to the hypocenter and honors the ocean water layer and sea floor upheaval also. Our model partly uses existing seismological information (hypocenter depth of 32 km, rupture length of 300 km and vertical slip of 4 m), provides a snapshot of episodic subduction of the Pacific Plate below the Atlantic Plate and its gravity response closely matches the observed gravity (RMS error of 3.4012×10^?13μGal), fully accounting for co-seismic mass redistribution including sea surface deformation. Our inferred rupture length, rupture velocity, average seismic moment magnitude and momentum, respectively, are 300 km, 4.49 km/s, 1.152×10²¹?1.8816×10²¹ N m and 2.319×10⁶ GNs, which fairly agree with the literature. Further, our model inferred momentum at the sea floor corresponds to an area pulse that led to Tsunami generation.     

Zirconology of ultrabasic rocks of the Karabash massif (Southern Urals)

Dating of zircon (SHRIMP) from dunite and harzburgite of the Karabash massif was carried out for the first time. Relics of ancient crystals (1940 ± 30 Ma in harzburgite, 1860 ± 16 Ma in dunite) provide evidence for the Paleoproterozoic age of the protolith. The morphological peculiarities of zircon crystals allow us to assume differentiation of the magmatic source 1720 m. y. ago. The major variety of zircons indicates stages of metamorphic evolution in the Neoproterozoic (530–560 Ma) and Early–Late Ordovician (440–480 Ma).     

The Disruption Index (DI) as a tool to measure disaster mitigation strategies

Apart from the loss of lives, injuries and homeless resulting from an earthquake, not only the economy and physical landscape are altered, but also the lives of citizens and their places of work are dramatically altered. If critical services and functions are disrupted for more than a reasonable time period, consequences can be severe. All communities are at risk and face potential disaster, if unprepared. The Disruption Index (DI) is a tool that allows the representation of a complex and multidimensional situation in a concise and easier way, providing institutions and communities with a way to identify the global earthquake impact in a geographical area, the elements at risk, and the means to reduce it. In the present paper, after a short review of the concept of DI, its geographic (spatial) distribution is developed and an application to some cities in Algarve (Portugal) is made. Then, the use of DI in the context of measuring the risk reduction for alternative disaster mitigation strategies is introduced and illustrations are presented.     

Energy partitioning over a semi‐arid shrubland in northern China

During the last decade, the widely distributed shrublands in northern China have shown significant signs of recovery from desertification, the result of widespread conservation practices. However, to support the current efforts in conservation, more knowledge is needed on surface energy partitioning and its biophysical controls. Using eddy‐covariance measurements made over a semi‐arid shrubland in northwest China in 2012, we examined how surface energy‐balance components vary on diurnal and seasonal scales, and how biophysical factors control bulk surface parameters and energy exchange. Sensible heat flux (H) exceeded latent heat flux (λE) during most of the year, resulting in an annual Bowen ratio (β, i.e. H/λE) of 2.0. λE exceeded H only in mid‐summer when frequent rainfall co‐occurred with the seasonal peak in leaf area index (LAI). Evapotranspiration reached a daily maximum of 3.3 mm day^?1, and summed to 283 mm yr^?1. The evaporative fraction (EF, i.e. λE/R_n), Priestley–Taylor coefficient (α), surface conductance (g_s) and decoupling coefficient (Ω) were all positively correlated with soil water content (SWC) and LAI. The direct enhancement of λE by high vapour pressure deficit (VPD) was buffered by a concurrent suppression of g_s. The g_s played a direct role in controlling EF and α by mediating the effects of LAI, SWC and VPD. Our results highlight the importance of adaptive plant responses to water scarcity in regulating ecosystem energy partitioning, and suggest an important role for revegetation in the reversal of desertification in semi‐arid areas. Copyright © 2015 John Wiley & Sons, Ltd.     

Correction of inertial oscillations by assimilation of HF radar data in a model of the Ligurian Sea

This article aims at analyzing if high-frequency radar observations of surface currents allow to improve model forecasts in the Ligurian Sea, where inertial oscillations are a dominant feature. An ensemble of ROMS models covering the Ligurian Sea, and nested in the Mediterranean Forecasting System, is coupled with two WERA high-frequency radars. A sensitivity study allows to determine optimal parameters for the ensemble filter. By assimilating observations in a single point, the obtained correction shows that the forecast error covariance matrix represents the inertial oscillations, as well as large- and meso-scale processes. Furthermore, it is shown that the velocity observations can correct the phase and amplitude of the inertial oscillations. Observations are shown to have a strong effect during approximately half a day, which confirms the importance of using a high temporal observation frequency. In general, data assimilation of HF radar observations leads to a skill score of about 30% for the forecasts of surface velocity.     

Nutrient interleaving below the mixed layer of the Kuroshio Extension Front

Nitrate interleaving structures were observed below the mixed layer during a cruise to the Kuroshio Extension in October 2009. In this paper, we investigate the formation mechanisms for these vertical nitrate anomalies, which may be an important source of nitrate to the oligotrphoc surface waters south of the Kuroshio Extension Front. We found that nitrate concentrations below the main stream of the Kuroshio Extension were elevated compared to the ambient water of the same density (σ _?? = 23.5–25). This appears to be analogous to the “nutrient stream” below the mixed layer, associated with the Gulf Stream. Strong turbulence was observed above the vertical nitrate anomaly, and we found that this can drive a large vertical turbulent nitrate flux \(>\mathcal {O}\) (1 mmol N m^?2 day^?1). A realistic, high-resolution (2 km) numerical simulation reproduces the observed Kuroshio nutrient stream and nitrate interleaving structures, with similar lateral and vertical scales. The model results suggest that the nitrate interleaving structures are first generated at the western side of the meander crest on the south side of the Kuroshio Extension, where the southern tip of the mixed layer front is under frontogenesis. Lagrangian analyses reveal that the vertical shear of geostrophic and subinertial ageostrophic flow below the mixed layer tilts the existing along-isopycnal nitrate gradient of the Kuroshio nutrient stream to form nitrate interleaving structures. This study suggests that the multi-scale combination of (i) the lateral stirring of the Kuroshio nutrient stream by developed mixed layer fronts during fall to winter, (ii) the associated tilting of along-isopycnal nitrate gradient of the nutrient stream by subinertial shear, which forms vertical interleaving structures, and (iii) the strong turbulent diffusion above them, may provide a route to supply nutrients to oligotrophic surface waters on the south side of the Kuroshio Extension.     

A Nonlinear Model of Contaminant Transformations in an Aquatic Environment

A nonlinear model of the decomposition of a multicomponent contaminant is developed with allowance made for the distribution of components over their reactivity. Model application is illustrated by the analysis of published empirical data on organic matter biodegradation in water column and bottom sediments, in an activated-sludge bioreactor, and the biological absorption and enzymatic destruction of organic matter by macrophytes. Photodestruction, chemical destruction, and sedimentation are also considered. The nonlinear model is compared with a first-order reaction equation.__________Translated from Vodnye Resursy, Vol. 32, No. 3, 2005, pp. 322–336.Original Russian Text Copyright © 2005 by Dolgonosov, Gubernatorova.     

Trace elements in ocean ridge basalts

A correlary of sea floor spreading is that the production rate of ocean ridge basalts exceeds that of all other volcanic rocks on the earth combined. Basalts of the ocean ridges bring with them a continuous record in space and time of the chemical characteristics of the underlying mantle. The chemical record is once removed, due to chemical fractionation during partial melting. Chemical fractionations can be evaluated by assuming that peridotite melting has proceeded to an olivine-orthopyroxene stage, in which case the ratios of a number of magmaphile elements in the extracted melt closely match the ratios in the mantle. Comparison of ocean ridge basalts and chondritic meteorites reveals systematic patterns of element fractionation, and what is probably a double depletion in some elements. The first depletion is in volatile elements and is due to high accretion temperatures of a large percentage of the earth from the solar nebula. The second depletion is in the largest, most highly charged lithophile elements (“incompatible elements”), probably because the mantle source of the basalts was melted previously, and the melt, enriched in these elements, was removed. Migration of melt relative to solid under ocean ridges and oceanic plates, element fractionation at subduction zones, and fractional melting of amphibolite in the Precambrian are possible mechanisms for depleting the mantle in incompatible elements. Ratios of transition metals in the mantle source of ocean ridge basalts are close to chondritic, and contrast to the extreme depletion of refractory siderophile elements, the reason for which remains uncertain. Variation of ocean ridge basalt chemistry along the length of the ridge has been correlated with ridge elevation. Thus chemically anomalous ridge segments up to 1000 km long appear to broadly coincide with regions of high magma production (plumes, hot spots). Basalt heterogeneity at a single location indicates mantle heterogeneity on a smaller scale. Variation of ocean ridge basalt chemistry with time has not been established, in fact, criteria for recognizing old oceanic crust in ophiolite terrains are currently under debate. The similarity of rare earth element patterns in basalt from ocean ridges, back-arc basins, some young island arcs, and some continental flood basalts illustrates the dangers of tectonic labeling by rare earth element pattern.