Trophic state assessment of Bhindawas Lake,Haryana, India

Trophic state allows for identification of problems and pressures that an ecosystem faces as well as demarcation of remedial measures. This study focuses on spatial and temporal variations in the trophic state and detection of possible causes of its divergence in Bhindawas Lake, India. The trophic state of the lake undulated between eutrophic and hyper-eutrophic state throughout the study period. Higher phosphorus concentration within the lake ecosystem is the dominant causal factor for its eutrophic state. The influence of other water quality parameters has also been analyzed using Spearman’s coefficient of correlation. Deviations between trophic state index (TSI)-chlorophyll-a (Chl-a), TSI-total phosphorus (TP), and TSI-Secchi depth (SD) pointed out that the lake is principally phosphorus limited, and its trophic status is influenced by non-algal turbidity to a large extent. Spatial analysis of trophic levels in geographic information system (GIS) helped in identification of pollution sources and chemical attributes affecting the trophic state of the lake. This study provides a rationale for further investigation of nutrient and sediment loading into the lake system and development of sustainable management and conservation strategy identifying suitable measures ascertaining the ecosystem integrity.     

Macrophyte species composition and structure along littoral region in relation to limnological variables of a tropical wetland ecosystem

The composition and structure of macrophyte communities of the littoral region of Bhindawas wetland (India) was investigated. Two hypotheses were tested: (1) if limnological variables such as water chemistry and soil parameters are important determinants of species composition and abundance and (2) what is the variance in species richness and composition within the wetland. Twenty-eight macrophyte species belonging to 17 different families were identified with relatively low species diversity and richness (H′?=?2.09; Margalef index?=?1.12). Eichhornia crassipes, attained the highest relative frequency (22.69%), followed by Salvinia natans, Paspalum paspaloides, Phragmites karka, Cynodon dactylon and Cyperus alopecuroides. The first and second axis of CCA ordination explained 38.4% and 28.5% of the total variance of species–limnological variables relationship, respectively. Water-related variables (dissolved oxygen, pH and nitrate concentration) and soil nutrient factors (soil carbon and phosphorus levels) were significantly correlated to macrophyte distribution. Sampling sites formed two distinct groups based on cluster analysis, indicating varying ecological conditions. Generally, composition and abundance of macrophytes evince highly productive nature of the lake, while dominance of invasive species like E. crassipes and S. natans indicates high influence of increased nutrient levels and anthropogenic activities in the catchment on lake macrophyte composition.     

Molecular and functional characterisation of cadmium-resistant Proteus vulgaris strain KNP3 to unravel its resistance mechanistic

Cadmium-resistant Proteus vulgaris strain KNP3 was originally isolated from the soil of Panki Thermal Power Plant, Kanpur, India. The strain was effective under in situ conditions for improving the physiological parameters of soybean plants. Nevertheless, the concentration of cadmium was significantly decreased in both plants and soil in the presence of this bioinoculant. Moreover, to unravel the mechanism involved in cadmium resistance, plasmid DNA was isolated from the strain and subjected to amplification of the czc gene, which is responsible for the efflux of three metal cations, viz. Co, Zn and Cd, from the cell. Further, the amplicon was cloned into pDrive cloning vector and sequenced. When compared with the available database, the sequence homology of the cloned gene showed the presence of a partial czcA gene sequence, thereby indicating the presence of an efflux mechanism for resistance in the strain. These results were further confirmed by atomic absorption spectroscopy, scanning electron microscopy and EDAX analysis.