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This paper conceptualises the factors responsible for water quality change in the aquifer on the basis of a study of flow dynamics, hydro-chemical, and bacteriological processes in a gypsum, lignite, oil, and gas-rich Barmer sedimentary basin in India. The change in colouration, odour, and presence of gases in flowing wells has been analysed. The study revealed that such a change in the quality of the water is mainly occurring in those wells that are located in the transition zone between unconfined and confined parts of the same aquifer. The field and lab analyses have further revealed the presence of pyrites, other iron-rich minerals, hydrogen sulphide (H2S), carbon dioxide (CO2), and methane (CH4) gases in the aquifer. The study suggests that changes in flow dynamics, hydro-chemical equilibrium, and microbiological processes like sulphate reduction, methanogenesis, and reverse methanogenesis are responsible for such changes in groundwater quality. The change in water quality in the unconfined parts of the aquifer is mainly due to in situ pyrite dissolution, bacteria-mediated sulphate reduction, or reverse methanogenesis taking place in the nearby confined parts of the aquifer. The presence of CH4 in non-flowing wells or while drilling new wells appears to be biogenic in nature and has migrated from deeper, confined parts of the same aquifer. The overexploitation of the aquifer has changed the flow dynamics and hydro-chemical equilibrium within the aquifer, and it has prompted the migration of gases from deeper, confined parts of the same aquifer. The water quality change is more prominent in the transitional zone between unconfined and confined parts of the aquifer. [ABSTRACT FROM AUTHOR]

Quantification of greenhouse gas emissions is a critical research gap for space cooling and refrigeration applications in Indian commercial buildings. This is especially relevant as these services are expected to grow rapidly in future driven by economic growth and urbanisation. This paper focuses on these two applications which are highly energy and emission intensive, and quantifies their carbon dioxide (CO) and hydrofluorocarbon (HFC) emissions through soft-linking a top-down model with a bottom-up approach. An integrated assessment modelling framework Global Change Assessment Model (GCAM)-IIM is used for modelling energy-related emissions under a business-as-usual scenario. In addition to CO emissions occurring from electricity use, cooling and refrigeration in commercial buildings emit another set of highly potent greenhouse gases, emanating from application of HFCs as coolant. HFCs substitute their ozone-depleting precursors in these applications. Countries across the world have agreed to phase down HFCs under the Montreal Protocol. Before we can analyse cost-effective options to bring down these emissions, it is important to quantify and assess the amount of emissions that could be avoided in the future. Our research sets up a baseline for carbon dioxide and HFC emissions from India for the commercial air-conditioning and refrigeration sectors and finds the potential HFC emission mitigation due to the Kigali Amendment. A detailed bottom-up modelling of these emissions is undertaken and it is found that, if unabated, the HFC emissions from commercial sector will surge from mere 1.8 million tonne (Mt) COe in 2015 to 211 Mt COe in 2050, whereas energy-related CO emissions from commercial air-conditioning and refrigeration will rise from 37 to 297 Mt COe in the same period. We also highlight the role of management practices and regulation for curbing HFC emissions which is especially relevant for the commercial building sector. [ABSTRACT FROM AUTHOR]

Energy and energy services are the backbone of growth and development in India and is increasingly dependent upon the use of fossil based fuels that lead to greenhouse gases (GHG) emissions and related concerns. Algal biofuels are being evolved as carbon (C) -neutral alternative biofuels. Algae are photosynthetic microorganisms that convert sunlight, water and carbon dioxide (CO) to various sugars and lipids Tri-Acyl-Glycols (TAG) and show promise as an alternative, renewable and green fuel source for India. Compared to land based oilseed crops algae have potentially higher yields (5-12 g/m/d) and can use locations and water resources not suited for agriculture. Within India, there is little additional land area for algal cultivation and therefore needs to be carried out in places that are already used for agriculture, e.g. flooded paddy lands (20 Mha) with village level technologies and on saline wastelands (3 Mha). Cultivating algae under such conditions requires novel multi-tier, multi-cyclic approaches of sharing land area without causing threats to food and water security as well as demand for additional fertilizer resources by adopting multi-tier cropping (algae-paddy) in decentralized open pond systems. A large part of the algal biofuel production is possible in flooded paddy crop land before the crop reaches dense canopies, in wastewaters (40 billion litres per day), in salt affected lands and in nutrient/diversity impoverished shallow coastline fishery. Mitigation will be achieved through avoidance of GHG, C-capture options and substitution of fossil fuels. Estimates made in this paper suggest that nearly half of the current transportation petro-fuels could be produced at such locations without disruption of food security, water security or overall sustainability. This shift can also provide significant mitigation avenues. The major adaptation needs are related to socio-technical acceptance for reuse of various wastelands, wastewaters and waste-derived energy and by-products through policy and attitude change efforts. [ABSTRACT FROM AUTHOR]

The micrometeorological technique of eddy covariance is a powerful tool for characterizing the carbon (C) budget of terrestrial ecosystems. Eddy covariance method was used for estimating Net Ecosystem Exchange (NEE) of carbon dioxide between atmosphere and revegetated manganese mine spoil dump at Gumgaon, India. In this paper, we analyzed the diel CO flux pattern and its response to various physical environmental conditions. The carbon balance of terrestrial ecosystems is particularly sensitive to climatic changes. Study of diel pattern of CO flux showed that carbon uptake was dependent on sunlight. Effect of temperature and latent heat on the CO flux showed that rate of CO uptake increased proportionally, but later declined due to various factors like stomatal response, high evaporative demand, circadian rhythm and/or a combination of all three. Net ecosystem production of revegetated land was found to be 28.196 KgC/ha/day whereas average net carbon release by the ecosystem, through respiration was observed to be 5.433 KgC/ha/day. Thus, quantifying net carbon (C) storage in degraded land is a necessary step in the validation of carbon sequestration estimates and in assessing the possible role of these ecosystems in offsetting adverse impacts of fossil fuel emissions. [ABSTRACT FROM AUTHOR]

Fuelwood plays an important role in the rural economy of the developing countries of Asia and Africa. Optimizing energy fixation in forest trees through high density energy plantations (HDEP), gasification of wood, and conversion of forest tree biomass, are some of the potential areas whereby additional research and development input for efficient management of atmospheric carbon in our energy system can be incorporated. For example, the photosynthetic efficiency of forest trees is rarely above 0.5%, which on the basis of theoretical considerations can be increased by up to 6.6%. Thus there is an ample scope to improve the efficiency up to 1%, which amounts to doubling of the productivity of the forests. Recent policy changes and experiences with wood-based bio-energy programmes in several countries indicate that woodfuels may become increasingly attractive as industrial energy sources. Use of biodiesel and the formulation of a project for undertaking 13.4 million ha of Jatropha plantations in India highlight the seriousness with which the Government of India is promoting carbon neutral energy plantations. The cost of establishment of plantations primarily for fuel production and its conversion to energy are major deterrents in this pursuit. Some of the issues in developing countries, like low productivity on marginal lands, degraded forest lands, and unorganized units for biomass energy conversion, result in cost escalation as compared to other energy sources. This paper revisits the scope for raising energy plantations, a comparison of the direct and indirect mitigation potential uses of plantations as an adaptation strategy through reforestation and afforestation projects for climate change mitigation and socio-economic issues to make this venture feasible in developing countries. [ABSTRACT FROM AUTHOR]

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India has the largest dairy industry in the world and accounts for a significant share of the global emission of livestock methane ( CH 4 ), a potent greenhouse gas (GHG). While previous works have examined the large-scale livestock CH 4 emissions in India, bottom-up studies are essential to account for the diverse farm conditions and practices across the subcontinent. We developed a Methane Calculator for Indian livestock sector using the Intergovernmental Panel on Climate Change (IPCC) Tier 2 methodology for estimating methane emissions from enteric fermentation and manure management. Using this calculator, we undertook a study of emissions from four dairy farms in the tropical coastal district of Thiruvananthapuram, Kerala, in June 2019. Livestock population and milk production data were collected from the four farms, to compute a mean CH 4 emission of 0.7183 kg CO 2 equivalents/kg of fat and protein corrected milk (kg CO 2 e/kg FPCM), with a notable farm-to-farm variability (63.3%). Having implemented the latest available guidelines outlined by the IPCC, our results are a valuable new addition to the existing body of knowledge in the measurement of dairy farm GHG emissions. We present this as a pilot study, demonstrating a simple method to perform bottom-up investigations of dairy GHG emissions and further formulate policy interventions and mitigation strategies at the farm level. [ABSTRACT FROM AUTHOR]

Carbon capture and storage is a necessary action for the reduction of CO2 emissions, and thereby mitigation of climate change and its impacts. Especially, in India, with its growing fuel needs and very little attention paid towards carbon capture and storage, mineral carbonation technology is a suitable option as it is cost-effective and could be retrofitted to existing plants that emit CO2. Given the development of carbon capture and storage technology, this study attempts direct mineral carbonation of steelmaking slag with flue gas. Response surface methodology was employed to design gas-solid and slurry phase aqueous carbonation experiments. A maximum reduction of about 36.1% was achieved through aqueous carbonation at 61.1 °C, 46.24 bar, and a liquid-to-solid ratio of 14.5, corresponding to a sequestration capacity of 127.4 g of CO2/kg of slag. The temperature was found to be the most vital parameter in both the aqueous and gas-solid carbonation processes. Regression models used to study the carbonation process were found to be statistically significant. The carbonated slag consisted of mineral phases, namely, calcite and dolomite. The results demonstrated the sequestration potential of Indian steelmaking slag with flue gas. Carbonation of steelmaking slag with flue gas poses to be a promising option for the development of carbon capture and storage technology in the country. [ABSTRACT FROM AUTHOR]

The reported incidence of shoulder tip pain after laparoscopic cholecystectomy was 30%–50%. The aim of the present randomized controlled study was to compare the effects of low-pressure (08–10 mm Hg) vs. standard-pressure (13–15 mm Hg) pneumoperitoneum in patients undergoing laparoscopic cholecystectomy. One hundred patients between 18 and 70 years undergoing laparoscopic cholecystectomy were included. Group A and group B patients underwent low-pressure and standard-pressure pneumoperitoneum laparoscopic cholecystectomy respectively. Post-operative shoulder tip pain and post-operative abdominal pain were measured using visual analogue scale score at 2 h, 8 h, 24 h and 48 h after surgery. The primary outcome measures were the incidence and severity of post-operative shoulder tip pain, whereas secondary outcome measures were the incidence and severity of abdominal pain. Intergroup comparison of categorical and continuous variables was done using the chi-square test/Fisher's exact test and unpaired 't' test respectively. The incidence and severity of post-operative shoulder tip pain at 2 h, 8 h, 24 h and 48 h was significantly higher in group B as compared to group A. The incidence of post-operative abdominal pain at 48 h was significantly higher in group B as compared to group A. The severity of post-operative abdominal pain at 24 h and 48 h was significantly higher in group B as compared to group A. Low-pressure laparoscopic cholecystectomy significantly decreases the incidence and severity of post-operative shoulder tip and abdominal pain. Routine use of low-pressure pneumoperitoneum for the alleviation of post-operative pain following laparoscopic cholecystectomy is recommended. [ABSTRACT FROM AUTHOR]

Termites are dominant soil macro-fauna in tropical forests, yet remain an uncertain component of the carbon budget in many regions. We investigated CH4 and CO2 flux patterns from termite mounds and background soils of moist tropical deciduous forests in Indian lower Himalaya from April 2015 till March 2016 using static closed chamber technique. The relation between gas fluxes and soil moisture as well as temperature were examined. Termite (Odontotermes obesus) mounds were significant localized source of CH4 (0.38 ± 0.01 mg m−2 h−1) and CO2 (1837 ± 40 mg m−2 h−1) amidst CH4 consuming (– 0.028 ± 0.001 mg m−2 h−1) or lower CO2 emitting (1120 ± 19 mg m−2 h−1) background forest soils. Gas fluxes from termite mounds were seasonally bimodal (monsoon flux being highest followed by a second mild peak in winter) and diurnally variable. Soil moisture was a significant determinant of CH4 and CO2 fluxes from termite mounds, explaining more than 50% variability. In the case of background forest soils, the combined effect of soil moisture and temperature best explained CO2 and CH4 flux variation. On scaling up, termite mounds contributed negligibly (0.3%) to total soil CO2 emission while mound-mediated CH4 emission offset net soil CH4 uptake by 2.0%. Our results suggest considerable role of termite mounds in influencing source–sink capacity of forest soils. Present data are crucial in reducing error and uncertainty due to spatiotemporal variations in case of large-scale predictions. We suggest careful future land use decisions to minimize the contribution of mound-building termites to net soil CO2 and CH4 flux from this region. [ABSTRACT FROM AUTHOR]

We estimate carbon mitigation cost (CMC) and the factors determining change in CMC using environmental production function. The CMC index is defined as the ratio of maximum production of electricity under unregulated and regulated production technology. Change in CMC index is decomposed into technical change, scale change and change in the level of CO2 emissions. The production function is estimated for 45 coal-fired thermal power plants over the period of 2008–2012 using data envelopment analysis. Decomposition of CMC change reveals that impacts of changes in scale of operation and CO2 emissions were more than the reduced costs realized due to technical changes. We find that the sample plants in Indian coal-fired thermal power sector had to sacrifice about 3.5% of electricity production amounting to 2005US$ 1702 million of revenue loss over the 5 years due to regulation of CO2 emissions. [ABSTRACT FROM AUTHOR]

Amongst all the anthropogenically produced greenhouse gases (GHGs), carbon dioxide (CO2) and methane (CH4) are the most important, owing to their maximum contribution to the net radiative forcing of the Earth. India is undergoing rapid economic development, where fossil fuel emissions have increased drastically in the last three decades. Apart from the anthropogenic activities, the GHGs dynamics in India are governed by the biospheric process and monsoon circulation; however, these aspects are not well addressed yet. Towards this, we have measured CO2 and CH4 concentration at Sinhagad, located on the Western Ghats in peninsular India. The average concentrations of CO2 and CH4 observed during the study period are 406.05 ± 6.36 and 1.97 ± 0.07 ppm (µ ± 1σ), respectively. They also exhibit significant seasonal variabilities at this site. CH4 (CO2) attains its minimum concentration during monsoon (post-monsoon), whereas CO2 (CH4) reaches its maximum concentration during pre-monsoon (post-monsoon). CO2 poses significant diurnal variations in monsoon and post-monsoon. However, CH4 exhibits a dual-peak like pattern in pre-monsoon. The study suggests that the GHG dynamics in the western region of India are significantly influenced by monsoon circulation, especially during the summer season. [ABSTRACT FROM AUTHOR]

Urbanization, industrialization and human population explosion not only increased the global power demand, but also led to global warming, pollution and climate change. This encouraged production of power from renewable sources, and thus, hydropower development has been focused. Today, there is more than 1300 GW of installed hydropower across the world, and most of the hydroelectric projects (HEPs) are multi-purpose which includes irrigation, flood and drought mitigation and tourism. Although credited as cheap, clean and green, recent studies demonstrate that the reservoirs of HEPs produce enormous quantities of greenhouse gases (GHGs), including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). A large number of estimates on the amount of GHGs from HEPs are available from across the globe. India is next only to USA and China in terms of number of large dams, and thousands of new dams are being planned or constructed, especially in the northeastern part. However, none of these projects have been analyzed in terms of production of GHGs, which is an essential prerequisite for developing such projects and to determine whether carbon emission reduction credits can be accorded or not. The present study was conducted to determine greenness of some of the HEPs of Northeast India in terms of emission of GHGs, and eligibility of the projects for carbon emission reduction credits. Further, the emission of different GHGs through various processes from the Tipaimukh HEP (Manipur) was estimated. In view of the findings, we have provided recommendations, which may be helpful in decision-making process. [ABSTRACT FROM AUTHOR]

The correspondence among energy use, carbon dioxide emissions, and growth is a matter of discussion among policymakers, economists, and researchers. It is not possible to deny that the concept of sustainable development inspires their enquiry into this arena. The primary aspiration of this work is to use machine learning techniques in the prediction of carbon dioxide emissions and growth by taking energy use as the input variable. Our findings suggest that the prediction accuracy of the relation between CO2 emission and growth can improve by using machine learning techniques. In this case, prediction using Adam optimization is better than stochastic gradient descent (SGD) in the context of carbon dioxide emissions and growth. Furthermore, the result highlights that the change from fossil fuel use to renewable energy use is a possible way to reduce carbon dioxide emissions without sacrificing economic growth. Hence, the policy has to be articulated in such way as to reduce fossil fuel use or increase energy efficiency, and at the same time, new investment has to be initiated in the renewable energy sector to promote economic growth in India. [ABSTRACT FROM AUTHOR]

Pink Stem Borer, Sesamia inferens Walker (Lepidoptera: Noctuidae) incidence has increased on graminaceous crops in the north-western plains of India during recent years. To understand the effect of climate change on the northward spread of the pest, studies on the growth and development of S. inferens on maize (Zea mays L.) were planned with combinations of temperature and CO2. The combinations were 27: 22 °C and 375 ppm of CO2, 32: 26 °C and 375 ppm of CO2, 27: 22 °C and 450 ppm of CO2 and 32: 26 °C and 450 ppm of CO2. Various developmental parameters of S. inferens were analyzed using analysis of variance for the main effects of temperature and CO2 and their interactions. At elevated temperature, the growth of egg, larval and pupal stages were faster and the developmental period decreased by 30.9%. At elevated CO2, the larval and pupal development delayed and there was 5.7% increase in developmental period. Both temperature and CO2 individually and in combination significantly influenced adult longevity. Adult longevity reduced 24.9% and 21.7% in male and female, respectively at elevated temperature. Whereas, at elevated CO2, adult longevity increased 7.6% in male and 6.8% in female, respectively. The fecundity was positively influenced (+10.8%) by elevated temperature and negatively (−14.4%) by elevated CO2. The effects of temperature and CO2 on the development of pink stem borer were opposite, with temperature being positive and predominant in influencing the biology of S. inferens. So, it is probable that the faster development of S. inferens on maize in the warm climate might slightly get mitigated by the adverse effect of elevated CO2. The overall effect of rapid development of pest population and damage on maize on large area basis needs to be further investigated. [ABSTRACT FROM AUTHOR]

Surface water partial pressure of carbon dioxide [pCO2 (water)], total alkalinity (TA), dissolved inorganic carbon (DIC), and air–water CO2 flux were measured in two estuaries of the Bay of Bengal namely Mahanadi and Dhamra. Though the annual average air–water CO2 fluxes at the Mahanadi and the Dhamra Estuaries were − 3.9 ± 21.4 (mean ± standard deviation) µmol m−2 h−1 and − 2.9 ± 11.6 µmol m−2 h−1, respectively, the intra-annual variation of air–water CO2 fluxes in the two estuaries was contrasting. Nonetheless, from the perspective of net primary productivity, the surface water of both the estuaries were found autotrophic throughout the study period with varying rates at different seasons and highest during summer months. Mahanadi Estuary acted as a CO2 source toward atmosphere during monsoon months, whereas, Dhamra Estuary acted as a source during pre-monsoon months. On the contrary, Mahanadi and Dhamra Estuaries acted as CO2 sink during pre-monsoon months and monsoon months, respectively. The salinity in Mahanadi Estuary was much lower compared to Dhamra, which indicated significant freshwater discharge rich in organic carbon, and the remineralization of this carbon to DIC during summer and monsoon months explained the CO2 source character. Whereas, in Dhamra, reduced freshwater flow and high turbidity were held accountable for net heterotrophic character of the water column during the post-monsoon months. The annual data set of air–water CO2 fluxes from these two estuaries produced from this study could be utilized in future to fill the data gap and upscale the Indian estuaries scenario from the perspective of blue carbon budgeting. [ABSTRACT FROM AUTHOR]

Active solar distillation system integrated with solar pond is the green energy system for desalination without negative environmental impact. This clean technology has potential to contribute a lot to water security, sustainable development, and world stability. In this article, results of the energy as well as exergy analysis performed on this novel system integrated with solar pond are presented. This theoretical analysis is carried out in the climatic conditions of New Delhi (India) during a typical summer day. The model and procedures can be helpful in the design, and performance investigation of the actual system anywhere in the world. The daily productivity, energy, and exergy efficiency of the passive solar still are found to be 5 L/m, 38.63 %, and 2.71 %, respectively, corresponding to a sum total of 24.436 MJ/m day solar energy input in passive mode. With the integration of solar pond in the active solar still, the daily productivity, energy, and exergy efficiency rises to about 9.5 L/m, 46 %, and 14.81 % respectively, for thermal energy input from 100 to 500 W/m during off-sunshine hours. The further improvement in the performance of the same system is observed if the thermal energy is supplied continuously (24 h) to the solar still in addition to incident solar radiation. The proposed system will meet the demand of freshwater in both rural and urban areas and help in reducing the load of CO emission on the environment, saving high grade energy consumed for desalination through conventional devices and technologies. [ABSTRACT FROM AUTHOR]

The above canopy carbon dioxide and water vapour fluxes were measured by micrometeorological gradient technique at three distant stations, within the world's largest mangrove ecosystem of Sundarban (Indian part), between April 2011 and March 2012. Quadrat analysis revealed that all the three study sites are characterized by a strong heterogeneity in the mangrove vegetation cover. At day time the forest was a sink for CO, but its magnitude varied significantly from −0.39 to −1.33 mg m s. The station named Jharkhali showed maximum annual fluxes followed by Henry Island and Bonnie Camp. Day time fluxes were higher during March and October, while in August and January the magnitudes were comparatively lower. The seasonal variation followed the same trend in all the sites. The spatial variation of CO flux above the canopy was mainly explained by the canopy density and photosynthetic efficiency of the mangrove species. The CO sink strength of the mangrove cover in different stations varied in the same way with the CO uptake potential of the species diversity in the respective sites. The relationship between the magnitude of day time CO uptake by the canopy and photosynthetic photon flux was defined by a non-linear exponential curve (R ranging from 0.51 to 0.60). Water vapour fluxes varied between 1.4 and 69.5 mg m s. There were significant differences in magnitude between day and night time water vapour fluxes, but no spatial variation was observed. [ABSTRACT FROM AUTHOR]

Cities across the globe are considered as major anthropogenic sources of greenhouse gases (GHG), yet very few efforts has been made to monitor ambient concentration of GHG in cities, especially in a developing country like India. Here, variations in the ambient concentrations of carbon dioxide (CO) and methane (CH) in residential, commercial, and industrial areas of Delhi are determined from fortnightly daytime observations from July, 2008 to March, 2009. Results indicate that the average daytime ambient concentration of CO varied from 495 to 554 ppm in authorized residential areas, 503 to 621 ppm in the slums or jhuggies in the unauthorized residential areas, 489 to 582 ppm in commercial areas, and 512 to 568 ppm in industrial areas with an average of 541 ± 27 ppm. CH concentration varied from 652 to 5,356 ppbv in authorized residential areas, 500 to15,220 ppbv in the unauthorized residential areas, 921 to 11,000 ppbv in the commercial areas, and 250 to 2,550 ppbv in the industrial areas with an average of 3,226 ± 1,090 ppbv. A low mid-afternoon CO concentration was observed at most of the sites, primarily due to strong biospheric photosynthesis coupled with strong vertical mixing. [ABSTRACT FROM AUTHOR]

Carbon dioxide, water vapour, air temperature and wind measurements at 10 Hz sampling rate were carried out over the coast of Arabian Sea, Goa (15°21′N, 73°51′E) in India. These observations were collected, in association with the surface layer turbulent parameters for the Arabian Sea Monsoon Experiment (ARMEX). In the summer monsoon period, concentration of CO was in the range of 550-790 mg m whereas the water vapour was in the range of 17.5-24.5 g m. The Fast Fourier Transform (FFT) analysis has been performed on these observations to investigate the spectral behaviour of CO and water vapour. The relation between CO and water vapour on various atmospheric scales has been proposed. CO and water vapour observations confirmed the existence of periodicities of large (11, 8 days), meso (5 days) and micrometeorological (20 min) scales. [ABSTRACT FROM AUTHOR]

Enteric fermentation in livestock is an important source of anthropogenic methane emission. India, with its large livestock population, is estimated to contribute 10.8 Tg of methane annually from this source. An evaluation of various methane mitigation options indicate that some of the available technologies like, diet supplementation with feed additive and molasses urea product are highly cost effective in reducing enteric methane emissions. The gross cost of methane abatement from use of feed additive monensin premix ranges from 0.6 to 1.8/ton CO2 equivalent, for buffaloes and indigenous cows, respectively. The gross cost of enteric methane mitigation from supplementing molasses urea products and dietary manipulation through increased concentrate feeding is much higher. But, as the monetary value of the increased milk production on application of these technologies was higher than the annual cost of reduction strategy for buffaloes and crossbred cows, the net costs of the former mitigation option was negative for buffaloes ( -28.1/ton CO2) and of the latter for crossbred cows ( -7.0/ton CO2,). The availability of cost-effective technologies suggest that the methane mitigation projects under CDM can be planned in the Indian dairy sector to the mutual benefit of countries with emission targets and India. The vast dairy animal population of India and resulting methane emissions provide good opportunity for these countries to buy reasonable quantum of emission credits from projects in India. Such projects will work to benefit India by providing a tool for technology transfer to increase animal productivity and attract capital that assists in more prosperous and environmental friendly milk production in the country. [ABSTRACT FROM AUTHOR]

In this study, we attempt to prospect potential bacterial isolates from mangrove sediments of Mangalavanam, Kerala, India, with positive carbonic anhydrase (CA) activity to sequester carbon dioxide by calcium precipitation process. Fifteen bacterial colonies (M1–M15) isolated were screened for their carbonic anhydrase enzyme production potential based on p-nitro phenol acetate assay. Based on the secondary screening, M3 and M8 were identified as the most potential for carbonic anhydrase production. The specific activity of the partially purified CA enzyme from M3 and M8 were 44 U mg−1 and 76 U mg−1 respectively. The enzyme activity increased by 1.6-fold upon precipitation by acetone (80%). The potential isolate which higher CA production, M8 was identified as Bacillus altitudinis based on 16S rDNA sequencing. Soil microcosm was established to study carbonic anhydrase production and CO2 sequestration ability of B. altitudinis M8 strain. B. altitudinis M8 strain could reduce CO2 by 75 ± 0.12% in microcosm composed of sterilized soil with bacteria (SSB) and by 97 ± 0.34% in microcosm with sterile soil with enzyme (SSE). Hence, the application of enzyme was found to be more effective in removing CO2 when compared to bacterial inoculum. To further understand the bio-mineralization ability of this microbial isolate, calcium precipitation assay was conducted. There was a reduction of 42.22 ± 0.23% of free calcium in the medium through calcite precipitation. The carbonic anhydrase-mediated calcium precipitation by B. altitudinis M8 strain could be effectively employed in the process of carbon dioxide sequestration. [ABSTRACT FROM AUTHOR]

A very severe cyclonic storm, Hudhud, made landfall at Visakhapatnam city, the central east coast of India, on 12 October 2014 and it is the most destructive cyclone to ever hit the Indian subcontinent since the past two decades. In order to examine its impact on the flux of trace gases into the atmosphere, a study was made in the coastal Bay of Bengal, off Visakhapatnam, after the cyclone and compared with the pre-cyclone conditions. Hudhud suppressed the vertical mixing of the water column due to the occurrence of strong salinity stratification associated with torrential rainfall. The land run-off and precipitation brought significant amount of ammonium to the coastal waters, resulting in increased pH. The increased pH shifted the inorganic carbon equilibrium towards the formation of bicarbonate, resulting in decreased partial pressure of carbon dioxide ( p CO 2) after the cyclone Hudhud. The undersaturation of carbon dioxide ( CO 2) and nitrous oxide ( N 2 O ) with respect to atmospheric equilibrium was observed during the post-cyclone period compared to the pre-cyclone period. About 80% of the post-cyclone decrease in N 2 O ( > 2 nM ) and p CO 2 (150– 200 μ atm ) was contributed by the dilution of coastal waters with the precipitated waters. In contrast, methane ( CH 4) concentrations were increased by 0.5–2.8 nM during the post-cyclone period than in the pre-cyclone period, and were attributed to the input of domestic sewage through land run-off. Dimethyl sulphide (DMS) and the total dimethyl sulphonio-propionate ( DMSP t) concentrations decreased by 0.4–3.9 and 0.2–6.0 nM, respectively, during the post-cyclone period in comparison with the pre-cyclone period and it was consistent with lower phytoplankton biomass during the former than the latter. The sea-to-air flux of CO 2 , N 2 O and DMS were 1.3 ± 0.5 mmol C m - 2 d - 1 , 0.9 ± 0.3 μ mol m - 2 d - 1 and 5.8 ± 3 μ mol m - 2 d - 1 during the pre-cyclone period, respectively. The corresponding values during the post-cyclone period were lower at - 2.0 ± 1 mmol C m - 2 d - 1 , - 0.4 ± 0.1 μ mol m - 2 d - 1 and 2.8 ± 2 μ mol m - 2 d - 1 , respectively. In contrast, the sea-to-air flux of CH 4 increased from 0.6 to 1.5 μ mol C m - 2 d - 1 from the pre- to the post-cyclone period. This study suggested that the cyclone Hudhud modified the magnitude of the biogenic gas flux to the atmosphere from the coastal Bay of Bengal than hitherto hypothesised. [ABSTRACT FROM AUTHOR]

The present study shows spatio-temporal variability in carbon dioxide (CO 2) in the mid-tropospheric region over India (0–32 o N , 60–100 o E ) during 2003–2011. The CO 2 data used in the study is retrieved from Atmospheric Infra-Red Sounder (AIRS). Analysis of 9 yrs of data shows that the CO 2 exhibits a linear increasing trend of 2.01 ppm/year. Besides displaying the linear increasing trend, data show strong seasonal and annual variability. Concentration of CO 2 is observed to be highest around April–May (summer months), which decreases by 4–5 ppm during the monsoon months. Seasonal decrease in CO 2 concentration appeared to be influenced by the monsoonal activity. Low OLR (proxy of convection) associated with high rainfall during summer monsoon via increasing vegetation index (NDVI) appears to be the primary cause for the seasonal decrease in CO 2 through photosynthesis. Correlation coefficient between CO 2 and NDVI is of the order of –0.90 suggesting vegetation as a seasonal sink of CO 2 . Decrease in CO 2 concentration takes place at a delay of 2–3 months of rainfall. However, convection seems to be another component, which causes uplifting of CO 2 during dry summer (April and May) making high concentration in the mid-troposphere as shown by increase in the planetary boundary layer (PBL) height in this period. Eastward propagating intra-seasonal oscillations with period 30–40 days in OLR anomalies are found to modulate (with a fluctuation of 1–2 ppm) mid-tropospheric CO 2 . Analysis of seasonal anomalies in CO 2 over four different regions (northern, southern, western and eastern) of India is also being investigated. The regional variability of CO 2 in northern region show marginal larger values suggesting more anthropogenic activities especially during late winter. [ABSTRACT FROM AUTHOR]

The diurnal and seasonal variation of soil carbon dioxide (CO2) flux was measured in the Pichavaram mangrove forest, the Southeast coast of India from February 2016 to October 2016 using an automated soil CO2 flux chamber system. Maximum soil CO2 efflux reached at 14:00 h and minimum at 00:00 h. The surface soil CO2 concentration ranged from 375 to 532 ppm with the mean 405 ± 18 ppm. The daily soil CO2 flux varied from near zero to about 7 μmol m−2 s−1 with a mean value of 2.4 ± 1.3 μmol m−2 s−1. The highest seasonal CO2 efflux from soil was during the summer and premonsoon seasons, whereas low flux values were recorded during the monsoon season. Soil CO2 efflux values were highly correlated with soil temperature. Tidal inundation during monsoon season, extreme drought condition in summer, and unusual precipitation are the major factors controlling the soil CO2 flux. [ABSTRACT FROM AUTHOR]