Morphometric and rheological study of lunar domes of Marius Hills volcanic complex region using Chandrayaan-1 and recent datasets

Marius Hills volcanic complex is one of the most important regions on the lunar surface having an abundant number of volcanic features like domes and cones. Systematic mapping of 106 domes/cones in the Marius Hills region was carried out in this study using high-resolution orthoimage and digital elevation models of Chandrayaan-1 and Kaguya missions. Various morphometric parameters like diameter, height, volume, flank slope, circularity index and form factor are derived for all the mapped domes. The rheological parameters, such as viscosity and eruption rate are estimated for isolated domes and cones superimposed over low domes. The morphometric and rheological properties of these domes are comparable to those located in the area near to Hortensius crater and other mare regions. Surface ages derived for a selected region in NW portion of the Marius Hills volcanic complex using crater size-frequency distribution technique yields ages of 2.98 and 1.91 Ga. It suggests that the domes in this region formed at about 2.98 Ga ago, and then, the younger mare basalts likely embayed this region about 1.98 Ga ago. Stratigraphic sequence of rilles, wrinkle ridge and domes shows that wrinkle ridges are the oldest, while the rilles are younger than the domes.     

Integrative Analysis of AltiKa-SSHa,MODIS-SST,and OCM-Chlorophyll Signatures for Fisheries Applications

The study focused on integrative signature analysis of synchronous chlorophyll concentrations (CC), Sea Surface Temperature (SST), and Sea Surface Height anomaly (SSHa) for fisheries applications. CC and SST were derived from IRS-OCM and MODIS, respectively, and SSHa was derived from SARAL-AltiKa, AVISO Ssalto/Duacs, and TOPEX/Poseidon. Spatial profiles were generated to visualize patterns of variability in signatures, their distribution, persistence, and interrelationship. The patterns of SST and SSHa signatures are co-varying in many cases indicating linearly related and the correlation was r = 0.79, whereas chlorophyll and SST/SSHa profiles are inversely related and the correlation was r = ?0.82 and ?0.73, respectively. Time series analysis of these variables shows areas of negative SSHa consist of high CC and relatively low SST. This suggests that negative SSHa areas consist of dense nutrient rich water and can be used as an indicator of enhanced biological production sites. Fishing operations data were procured from Fishery Survey of India (FSI). Fish catch in terms of catch per unit efforts (CPUE) were related with signatures of variables. High CPUE locations/contours were found in the vicinity of low SSHa/SST and high CC consisting waters.     

Assessment of bacterial diversity associated with crude oil-contaminated soil samples from Assam

In this study, we are reporting bacterial diversity in crude oil-contaminated soil of Assam, India. Integration of physiological community profiling, culture-dependent and culture-independent (metagenome) approaches, was employed to obtain a complete picture of the total bacterial diversity. Samples collected from 10 sites contaminated with crude oil ranging from 0.22 to 89.36% were analysed, and altogether 160 culturable bacteria were isolated (117 Gram-positive and 43 Gram-negative bacteria). Molecular identification showed the predominance of genera Lysinibacillus, Alcaligenes, Bacillus, Clostridium, Enterobacter and Pseudomonas. Conversely, denaturing gradient gel electrophoresis (DGGE) profiles of 16S rDNA phylotypes showed the predominance of Sphingomonas, Ralstonia, Sphingobium, Massilia, Acinetobacter and Pseudomonas. Both culture-dependent and culture-independent approaches resulted in 11 genera of which Bacillus and Pseudomonas were the key inhabitants creating most favourable bacterial milieu in the presence of crude oil contaminants. Metabolic fingerprints data depicted in PCA plot demonstrated that sites CTF-D-1 and Core-10 were most diverged. It was further confirmed that variations of bacterial species dominance in different sites were due to origin of hydrocarbon contamination. We here claim that the present findings is a first-hand report on combined physiological community profiling, culture-based and culture-independent approaches in assessing total bacterial diversity in crude oil-contaminated soil of Assam.     

Systemic analysis of soil microbiome deciphers anthropogenic influence on soil ecology and ecosystem functioning

Soil is a complex ecosystem with defined microbial community signatures, modulated by the interaction between biotic and abiotic factors. Amidst biotic factors, land usage have significant impact onto the soil microbial structure and ecosystem functioning. In the current study, metagenomic approach was used to decipher effect of hospital settings on soil microbiome structure and physiological functions. Physico-chemical properties analysis revealed that key elements for maintenance of soil microflora, such as organic carbon, nitrogen, phosphorus and sulfur were relatively diminished within hospital soil, compared to garden soil. Comparative microbial diversity analysis with 97,315 SSU rRNA gene sequences generated from both the soil samples highlight relatively low microbial diversity, with an enrichment for Acidobacteria and Bacteroidetes and decreased Proteobacteria/Acidobacteria ratio. Comparative shotgun metagenome sequence analysis further revealed a shift in the physiological role of soil microbiomes with change in soil usage. Genes for carbohydrate, sulfur, potassium and nitrogen metabolism were significantly (q value <0.05) higher in the garden soil; while the genes for phage, plasmid DNA, transposon and aromatic compound metabolism were significantly enriched within hospital soil. Thus, the current study highlights a correlation between soil biochemistry and microbial ecology based on land usage.     

Influence of spatially random soil on lateral thrust and failure surface in earth retaining walls

The present study investigates the influence of spatial variability of soil properties on the lateral thrust and failure surface of a 6?m high frictionless rigid earth retaining wall in active condition. The drained friction angle of the soil is modelled as a log-normal anisotropic random field in two dimensions, using the Cholesky decomposition technique. The effect of horizontal and vertical scale of fluctuation is observed on the lateral thrust. The failure surface in the backfill is found to be more or less similar for different combinations of spatial variability in vertical and horizontal directions. Monte-Carlo simulation technique is used to compute the probability of failure and to obtain the worst-case spatial variability configuration.