Growth of Plankton (Scenedesmus acutus (Chlorophyceae) and Moina macracopa (Cladocera)) on Domestic Wastewater

The population growth of the freshwater chlorophyte, Scenedesmus acutus and the cladoceran Moina macrocopa cultured in the laboratory and in microcosms of a wastewater treatment plant was studied. S. acutus was cultured in a defined algal medium and mixed with wastewater. On diets of S. acutus cultured using Bold medium or a mixture with wastewater, the peak densities of M. macrocopa were 6–7 ind. mL^?1, while on a diet of algae cultured on wastewater alone the cladoceran density fluctuated around 2 ind. mL^?1. Population growth rates of M. macrocopa, which ranged from 0.3 to 0.4 d^?1, were significantly lower on alga cultured in wastewater alone. The body size structure of M. macrocopa was larger on algae cultured in Bold medium than in wastewater. Peak densities of M. macrocopa were around 700 ind. L^?1 when the organic matter in the containers was supplemented with algae but it reached lower densities (400 ind. L^?1) when cultured on the organic matter in wastewater alone. Our study indicates that the nutrients in the final stages of wastewater treatment can support the growth of both phytoplankton and zooplankton.     

Application of drainage basin morphotectonic analysis for assessment of tectonic activities over two regional structures of the northeast India

The analysis of drainage basin morphotectonic indices is applied in assessment of the influence of tectonic activity on thirteen selected drainage basins of the streams having linear courses and flowing over two very prominent regional structures of northeast India, viz. the Belt of Schuppen and the Dauki fault. Such analysis has been made in order to assess the influence of tectonic activity of these structures on the morphology of the drainage basins of those streams.The different morphotectonic indices considered are: Basin elongation ratio, hypsometric integral, steepness index and profile concavity, drainage basin asymmetry, valley floor width to valley height ratio, longitudinal profiles, stream length gradient index and mountain front sinuosity. Results of the analysis of the morphotectonic indices of the drainage basins infer that morphology of both the streams and drainage basins have been influenced by the regional structures and the present tectonic status of these two structures varies from active to slightly active phase. No significant influence of lithology is seen in the distribution pattern of the anomalous knick points along the longitudinal profiles. The study also reveals that presently the state of tectonic activity is not uniform within the same regional structure and the Belt of Schuppen is relatively more active as compared to the Dauki fault.     

Hydrodynamic control of microphytoplankton bloom in a coastal sea

The influence of hydrodynamics on phytoplankton bloom occurrence/formation has not been adequately reported. Here, we document diurnal observations in the tropical Bay of Bengal’s mid-western shelf region which reveal microphytoplankton cell density maxima in association with neap tide many times more than what could be accounted for by solar insolation and nutrient levels. When in summer, phytoplankton cells were abundant and the cell density of Guinardia delicatula reached critical value by tide caused zonation, aggregation happened to an intense bloom. Mucilaginous exudates from the alga due to heat and silicate stress likely promoted and stable water column and weak winds left undisturbed, the transient bloom. The phytoplankton aggregates have implication as food resource in the benthic region implying higher fishery potential, in carbon dioxide sequestration (carbon burial) and in efforts towards improving remote sensing algorithms for chlorophyll in the coastal region.     

Estimating gross primary productivity of a tropical forest ecosystem over north-east India using LAI and meteorological variables

Tropical forests act as a major sink of atmospheric carbon dioxide, and store large amounts of carbon in biomass. India is a tropical country with regions of dense vegetation and high biodiversity. However due to the paucity of observations, the carbon sequestration potential of these forests could not be assessed in detail so far. To address this gap, several flux towers were erected over different ecosystems in India by Indian Institute of Tropical Meteorology as part of the MetFlux India project funded by MoES (Ministry of Earth Sciences, Government of India). A 50 m tall tower was set up over a semi-evergreen moist deciduous forest named Kaziranga National Park in north-eastern part of India which houses a significant stretch of local forest cover. Climatically this region is identified to be humid sub-tropical. Here we report first generation of the in situ meteorological observations and leaf area index (LAI) measurements from this site. LAI obtained from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) is compared with the in situ measured LAI. We use these in situ measurements to calculate the total gross photosynthesis (or gross primary productivity, GPP) of the forest using a calibrated model. LAI and GPP show prominent seasonal variation. LAI ranges between 0.75 in winter to 3.25 in summer. Annual GPP is estimated to be \(2.11\,\hbox {kg C m}^{-2} \, \hbox {year}^{-1}\).     

Developing a biosorbent from <Emphasis Type="Italic">Aegle Marmelos</Emphasis> leaves for removal of methylene blue from water

Dried, mature leaves of Aegle Marmelos tree were converted to a powder, which was used as a biosorbent for dyes in water with methylene blue as a case study. The biosorbent had a surface area of 52.63 mg/g, and FTIR spectra showed the presence of –COOH, –NH₂, –R–SC=O (thioester) and R1–S(=O, =O)-N(–R2, –R3) groups on the surface. The particles were found to be porous in nature from scanning electron micrographs, and EDX measurements showed the elements C, O, Na, Mg, K, Ca and Fe on the surface. Batch adsorption experiments showed that the adsorption of the dye was preferred at near-neutral conditions. Adsorption equilibrium was achieved in ~120 min with maximum dye uptake of 19.9 mg/g. Investigation into the kinetics of adsorption indicated that second-order kinetics gave the best fit to the experimental data, and a rate coefficient of 8.0 × 10^?2 to 32.3 × 10^?2 g mg^?1 min^?1 was obtained.     

Spatial homogeneity of extreme precipitation indices using fuzzy clustering over northeast India

Natural Hazards - Regionalization on the basis of the properties of hydro-meteorological data helps in identifying the regions reflecting the similar characteristics which could be useful in...     

Consolidation due to shear loads distributed over a rectangular area

The paper presents an analytical study of the consolidation of a semi-infinite clay layer subjected to a shear load distributed over a rectangular area. Biot's theory is made use of, along with the three displacement functions suggested by Verruijt. A complex Fourier and Laplace transformation technique enables the solution to be obtained in terms of non-dimensional parameters. Settlements and pore pressures under the loaded area are evaluated for two types of surface drainage conditions. Extension of the solutions to point loads is also suggested. The Mandel–Cryer effect is seen in the behaviour of the pore pressure.     

The deadliest stable continental region earthquake occurred near Bhuj on 26 January 2001

A large destructive earthquake occurred on 26 January 2001 in the region of Kutch, Gujarat, in Western India, with magnitude Mw 7.7. The earthquake caused very heavy damage and a large number of casualties with more than 20,000 deaths. A preliminary study of ground deformation, damage pattern and aftershock distribution is presented.     

Evaluation of irrigation management in a Canal Command area based on Agrometeorology and Remote Sensing

Efficacy of irrigation management of wheat and mustard crops grown in Western Yamuna Canal Command area was determined in the present study from agro-climatic data merged with Maximum Likelihood Classified (MXL) satellite image and from irrigation scheduling efficiencies obtained through FAO model CROPWAT. For computing irrigation scheduling efficiencies, amount of water supplied at different growth stages, soil water depletion and crop water need have been taken into account. Agro-meteorological data in combination with MXL classified crop map approximated the deficiency of applied irrigation amount compared to requirement. Irrigations at 35-80 Days After Sowing (DAS) for two times of applications, 30-60-90 DAS for three, 21-50-80-110 DAS in case of four and 20-45-70-90-120 DAS in case of five irrigations have yielded better scheduling efficiencies for wheat than other times of applications in all soil associations.     

Landuse/Landcover change detection through remote sensing and its climatic implications in the godavari delta region

Interpretation of multi-date satellite imagery has revealed changes in land use/land cover pattern in the Godavari deltaic region during the past 26 years. The area under intensive agriculture has increased from 1459 to 3500 km² and the extent of wetland from 368 to 648 km² during the period 1973-1999, while the seasonal fallow has decreased by 2321 km². Analysis of the climatic data of 1970-1998 from different stations covering the entire 5100 km² area of the delta indicated that the day time temperatures have decreased by 0.2° C to 0.7° C, while the night time temperatures have increased by 0.5° C to 0.6° C during the past three decades. At the same time the rainfall has increased by about 75 to 479 mm. These trends in the climatic parameters arc attributed to the increased vegetation cover and wetland extent in the Godavari deltaic region.