•Heterogeneity in microbial degradation response reflected ecosystem stress.•Optimum but highand faster enzyme activity was specific for high stress condition.•Final stress categorized as severely stress, moderately stress and poorly stress.•Molecular biomarkers for ecological resilience.

Winter reduction of fish growth is one of the major concerns in aquaculture. Using the principle of greenhouse mediated raised temperature, the issue has been addressed by examining the growth responses of some tropical fishes in polyculture (rohu, mrigal, bata, Japanese punti, grass carp, common carp, magur, freshwater prawn) and two stocking ratios (80: 20 and 20: 80) with surface and column feeder (catla, silver carp, rohu, Japanese punti and bata) and bottom feeder (mrigal and common carp). Advanced fry of these fishes were introduced separately in solar heated greenhouse and in open polyhouse (13 x 1.5 x 2m(3)) placed in triplicate in a pond and reared for 120 or 98 days during the winter for two consecutive years. The rate of survival (20-83%) and net weight gained by different species of fish were distinctly higher in closed set up (0.22-2.95 g/day) than in open (4-66%; 0.11-1.80 g/day) ones in both trials. Among the species, warmth induced net weight gain was maximal for Japanese punti (196 g), followed by rohu (159 g), mrigal (115 g), grass carp (104 g), bata (36 g) and freshwater prawn (28 g) in polyculture. The frequency distribution of harvested fishes was skewed towards large fishes in solar heated greenhouse and smaller ones in open units. Water temperature ranged from 21.6-28.1 degrees C and 17.2-23.7 degrees C in the closed and open units, whereas mean temperature remained 4.5-5 degrees C higher in the former than in latter. There was no marked differences in total alkalinity (219-231 mg/l), inorganic carbon (289-417 mg/l), organic carbon (4.27-4.52 mg/l), dissolved oxygen (6.61-6.75 mg/l), total dissolved solids (420.48-423.74 mg/l) and conductivity (549.83-563.29 mu s/cm) between the closed and open enclosures, and remained within the range for fish culture. The score values of the sum total of the integrated ecological conditions revealed that similar to 5 degrees C rise in water temperature during winter enhanced as high as 36% increased yield of fish (2546 kg/ha) over open units mediated through microbial driven augmented manure mineralization leading to increased primary productivity, zooplankton abundance and ecological integrity. In essence, the solar heated greenhouse would be of considerable use for circumventing the retarded growth during winter in tropical fishes.

Anthropogenic and natural hazards put aquatic ecosystem under severe stress due to organic and inorganic pollutants and calls for remediation. Eco-remediation, an ecological blessing for ecosystem stabilization refers to the restoration of the perturbing ecosystem to its original balanced state with a multi-purpose approaches for removing pollutants by vast array of biological components. Aquatic habitats and biodiversity are adversely affected by indiscriminate pollution along with rising levels of carbon dioxide. To overcome the aquatic stress of various pollutants, microorganisms significantly imparting crucial roles in environmentally sustainable bioremediation approaches by adapting themselves in order to survive in perturbed ecosystems resulting in the environmental remediation. This chapter attempts to deal with eco-remediation of ecosystems perturbed by various hazardous pollutants by focusing the degrading and transforming of contaminants into less toxic forms by microbes and carbon sequestration through heterotrophic pathway applying different ex situ or in situ detoxifying mechanisms. Considering the high eco-remedial efficiencies, microbial eco-remediation technologies could be applied as an emerging approach in restoring perturbed aquatic ecosystems in ecological engineering systems.

Two new dicyanamide-interlaced tetranuclear Zn(II)-Schiff-base complexes [Zn-2(L-OMe)(mu_dca-kappa N-1 kappa N-5)(mu-dca-kappa N-1)](2) (1) and [Zn-2(L-OEt)(mu_dca-kappa N-1 kappa N-5)(mu-dca-kappa N-1)](2) (2) were synthesized by using salicylaldimino type Schiff bases (H2LOMe) and (H2LOEt) respectively. Schiff base ligands and the complexes were characterized by elemental analyses, powder X-ray diffraction, FT-IR, FT-Raman, H-1 NMR, C-13 NMR, UV-Vis, TGA and fluorescence spectroscopy. Dicyanamide modulated complexes were structurally characterized by single crystal X-ray diffraction studies. X-ray crystal structure divulges that the two complexes are isostructural. In both the complexes, the Zn1 metal centers fulfill 5-coordinated distorted square pyramidal geometry having ZnN(3)O(2 )chromospheres where Schiff bases are mainly trapped in their complete deprotonated dianionic forms [L](2-), whereas Zn2 metal center attained distorted octahedral geometry. In both complexes two asymmetric units are connected by double mu(1,5)-dicyanamide ion thus forming Zn-4-nuclear metal complex. B3LYP/def2-TZVP level of theory (DFT) successfully applied in both complexes. The complexes (1-2) exhibit intraligand (pi -> pi *) fluorescence in DMSO solvent with lifetimes in the range 0.66-0.82 ns. In vitro antibacterial, membrane damage assay and anti-biofilm properties of both complexes are evaluated against some important Gram-positive and Gram-negative bacterial strains. Finally, the UV-Vis experimental spectral findings are well rationalized with the electronic distribution of HOMO-LUMO through TD-DFT level of calculations.

Spatial and seasonal variability of diversity, abundance and carbon sequestration potential of net-phytoplankton were examined across the sewage effluent of six wetlands in waste stabilization ponds used for the treatment of municipal wastewater cum fish culture. The values of the Shannon-Weiner diversity index for Myxophycaeae, Euglenophyceae, and Chrysophyceae were higher in the facultative pond compared to maturation ponds, whereas that of Bacillariophyceae was higher in later than in former. The gross and net primary productivity of phytoplankton ranged from 3.594 g C m(-2) d(-1) to 32.858 g C m(-2) d(-1) and 2.34 C m(-2) d(-1) to 15.227 C m(-2) d(-1), respectively. The P/R ratio varied from 1.365 to 5.729 in different ponds investigated. Two clear-cut zones were well recognized. The facultative pond with the supremacy of blue-green algae favoured immense carbon sequestration potential. The total phytocarbon biomass in the facultative pond (60,491 mg C m(-3)) was 2.5-4 folds higher than in subsequent maturation ponds. The carbon sequestration potential of the entire wastewater stabilization pond system was calculated to be 133,279 mg C m(-3). Further research is needed to prepare carbon budget by quantifying the carbon capture from atmosphere and emission into the atmosphere, if any through mud-water interactions of the bottom sediment. (C) 2018 Published by Elsevier B.V. on behalf of European Regional Centre for Ecohydrology of the Polish Academy of Sciences.

The responses of cellulase enzymes of three bacterial isolates and their impacts on cattle manure decomposition were assessed in a greenhouse model in vivo pond ecosystem. Fifty grams of fresh cattle manure was placed in a fastened nylon bag (mesh size ~ 50 μm dia.) and placed in triplicate in a plastic bucket with 10 l of pond water which was hung inside the enclosed polyhouse, semi-closed and open systems for 4 weeks. Samples of manure residue directly from nylon bag and water from manure leached bucket water, water, and soil from the enclosed polyhouse were collected for enzymatic assays, enumeration of aerobic cellulose decomposing and heterotrophic bacteria, and determination of water and soil quality parameters. Responses of cellulases to different temperatures in situ were also elucidated. The values of test bacteria, endoglucanase, exoglucanase and β-glucosidase, and organic carbon were significantly (P ˂ 0.05) higher in the closed system compared to semi-closed or open system. Priming of all the enzymes coupled with the peak of aerobic cellulose decomposing bacteria and heterotrophic bacterial populations occurred on the day 14 or 21 in vivo. Since the peaks of three cellulases of bacterial isolates (KUPH1, KUPH6, and KUPH8) were demonstrated between 35 and 40 °C, and that temperature coincided with temperature of the greenhouse model, this temperature range appeared to favor the growth of cellulose decomposing bacterial populations and involved cellulase enzymes.

Background and Objective: In view of scarcity of water resources due to huge amount of wastewater generated from population increase and industrialization, it has become a challenge to protect and conserve these water resources through proper treatment driven reuse.The present study was aimed at assessing the effectiveness of some natural and synthetic-adsorbent for eutrophication control by phosphate-P and nitrate-N removal from wastewater so that the resulting water can be safely reused for various economic-drivenactivities. Materials and Methods: Phosphate-P and nitrate-N removal potentials from municipal-wastewater of some natural (fly-ash, coarse-sand and cattle-dung-cake-ash and their mixture-combination) and synthetic (Ferrosorp, ferric-hydroxide, activated -alumina and their mixture-combination) adsorbents were tested in batch-experiment for 10 days at room temperature (30EC).Ten gram of each adsorbent was added to 500 mL of wastewater in battery jar.Different parameters (pH, phosphate-P, nitrate-N and available-P) were monitored using the standard protocol.Desorption of saturated Ferrosorp was also examined using different extractants.The fertilizer value of spent adsorbent (Ferrosorp) was tested for the growth of Bengal gram (Cicer arietinum) in pot.Results: Synthetic-adsorbents (activated-alumina, Ferrosorp and ferric-hydroxide) removed 92-93% phosphate-P, whereas both synthetic and natural (fly-ash, coarse-sand and cattle-dung-cake-ash) removed 100% NO 3 -N from wastewater within 10 days of contact time.The nutrient removal capacity of the test adsorbents was correlated with their porosity and surface area.Cattle-dung-cake-ash and fly-ash were also good adsorbents for removal of NO 3 -N.Though the amount of phosphate-P adsorbed by water with saturated Ferrosorp was relatively less (47.58%) than other extractants (75.50%), the spent Ferrosorp with soil revealed a pronounced effect on growth of Cicer arietinum. Conclusion:It is reasonable to conclude that Ferrosorp would be a low-cost and environmentally-sound sorbent for the treatment of phosphorous contaminated effluents and generated spent Ferrosorp could be used as potential fertilizer for enhancing crop-production.

The present study was carried out to assess the ecosystem of the Chhariganga, an oxbow lake in eastern India to assess the pollution due to jute retting and trophic status on broader aspects for its sustainable management.The physicochemical analyses of the studied oxbow lake showed the range with annual mean values of surface water temperature in ºC (11-37, 27.64±6.56),water transparency in cm (16-106, 45.82±23.39),water pH (7.4-8.8,8.17±0.34),DO (2.60-7.85,4.65±1.52ppm), BOD (1.10-6.40,2.98±1.59ppm),COD (70-90, 79±7.38ppm),NH 4 -N (0.026-0.093, 0.05±0.02ppm),NO 2 -N (0.008-0.08, 0.03±0.02ppm),NO 3 -N (0-2.459,0.81±0.69ppm),OP (0.067-0.62, 0.26±0.18ppm),total alkalinity (82-165, 120±24.03ppm),total hardness (70-138, 102.62±19.60ppm),GPP (0.30-1.80, 1.25± 0.47mgC/l/day), NPP (0.15-1.38, 0.95± 0.40mgC/l/day); sediment pH (6.8-7.9, 7.53±0.34)and sediment organic carbon in % (1.87-2.89,2.17±0.28).The highest mean values of BOD (4.59ppm), COD (86.67ppm),OP (0.50ppm), sediment organic carbon (2.29%) were observed during monsoon whereas the lowest values of oxbow lake water's transparency (27.00cm), pH (7.84), DO (3.63ppm) and NO 2 -N(0.01 ppm) contents were found during monsoon when jute retting process intensified in the oxbow lake.Compared to their values in pre-monsoon, mean values in monsoon showed an increase in BOD (182.57%) and OP content (167.64%)unlike reduction in water transparency (62.54%),GPP and NPP (both reduced by about 50%); The highest concentration of NH 4 -N and NO 3 -N were noticed during post-monsoon and OP during monsoon.The water transparency mean values showed sharp fall during monsoon from pre-monsoon.Physico-chemical analyses revealed that almost all parameters in oxbow lake did not show significant changes throughout the year unlike water transparency, BOD , NO 2 and especially OP content of water which otherwise showed significant changes throughout the year.The present semi-closed oxbow lake water was of poor to moderate quality and it was classified as oligo-mesotrophic in nutrient status with high to moderate organic pollution due to jute retting process which needs to be controlled and regulated for sustainable aquaculture in oxbow lake ecosystem.

A new pyrazole containing ligand, 5-methyl-3-formylpyrazole-N(4)-dihexylthiosemicarbazone (HMP(z)NHex(2)), and a host of its cobalt(III) and nickel(II) complexes, [Co(MP(z)NHex(2))(2)]X-2 center dot mH(2)O and [Ni(HMP(z)NHex(2))(2)]X-2 center dot nH(2)O (X = Cl, Br, ClO4, BF4 and NO3; m = 0 for Cl, Br, BF4 & NO3 and 1.5 for ClO4; n = 0 for Br, ClO4, BF4 & NO3 and 2 for Cl), respectively, have been synthesized and characterized by elemental analyses, magnetic measurements (polycrystalline state), H-1 NMR (for the ligand and its Co(III) complexes), electronic and IR spectral parameters. All the reported Co(III) and Ni(II) complexes are cationic in nature and behaving as 1:1 and 1:2 electrolytes, respectively, in MeOH. Electronic spectral data of the complexes categorize them as having distorted octahedral coordination geometry. IR spectral features (4000-450 cm(-1)) specify a monodeprotonated/neutral tridentate (NNS) function of the ligand, HMP(z)NHex(2) coordinating to the Co(III)/Ni(II) via the pyrazolyl (tertiary) ring nitrogen, azomethine nitrogen and thiolato/thioketo sulfur atom. H-1 NMR spectral data (in CDCl3 at 400 MHz) for the primary ligand and those of its Co(III) complexes are in agreement with the proposition of bonding sites evidenced from IR data. The single crystal X-ray data of I (C2/c (#15); monoclinic) and II (P-1 (#2); triclinic) have confirmed a CoN4S2 and a NiN4S2 octahedral coordination, respectively. The pair of monoprotic/neutral coordinating ligands is more or less orthogonal to each other in the complex species. The data obtained from DFT calculations are reasonably in agreement with the UV-Vis spectral assignment and the structures of the complex species. Although the ligand and the tested metal ion complexes are capable of inhibiting microbial growth, the cobalt complexes can be promoted as better antimicrobial agents.

Fish diversity in Oxbow lake is adversely impacted due to diverse anthropogenic activities like over-exploitation, indiscriminate use of fine meshed fishing gears, jute retting etc. To quantify the impact of such anthropogenic activities on fish diversity and aquatic health, a survey with seasonal analysis of diversity indices, relative frequencies and abundance status of native fish populations was conducted from April 2013 to March 2014 in a semi closed Oxbow lake in Nadia district in eastern India. The level of p<0.05 was accepted as statistical significance. Of the 33 native fish species recorded 33% belonging to 8 orders and 17 families fell under vulnerable or endangered categories. Native species like Amblypharyngodon mola, Chanda nama, Pethia ticto and Notopterus notopterus, Colisa fasciata, P. ticto, were the most dominant and frequent fishes. Shannon-Weiner diversity index was decreased by 41% by precipitating impact of monsoonal anthropogenic activities during post-monsoon. Low native fish diversity indices are pointers to poor ecosystem health status owing to intense adverse activities like jute retting, indiscriminate fishing aggravated by influx of turbid water from the river Ganga following episodic flood events during monsoon. Regulation and prevention of such anthropogenic activities are urgently warranted for sustainable conservation and management of the Oxbow lake.