CO<Subscript>2</Subscript>-fertilization and potential future terrestrial carbon uptake in India

There is huge knowledge gap in our understanding of many terrestrial carbon cycle processes. In this paper, we investigate the bounds on terrestrial carbon uptake over India that arises solely due to CO ₂ -fertilization. For this purpose, we use a terrestrial carbon cycle model and consider two extreme scenarios: unlimited CO₂-fertilization is allowed for the terrestrial vegetation with CO₂ concentration level at 735 ppm in one case, and CO₂-fertilization is capped at year 1975 levels for another simulation. Our simulations show that, under equilibrium conditions, modeled carbon stocks in natural potential vegetation increase by 17 Gt-C with unlimited fertilization for CO₂ levels and climate change corresponding to the end of 21st century but they decline by 5.5 Gt-C if fertilization is limited at 1975 levels of CO₂ concentration. The carbon stock changes are dominated by forests. The area covered by natural potential forests increases by about 36% in the unlimited fertilization case but decreases by 15% in the fertilization-capped case. Thus, the assumption regarding CO₂-fertilization has the potential to alter the sign of terrestrial carbon uptake over India. Our model simulations also imply that the maximum potential terrestrial sequestration over India, under equilibrium conditions and best case scenario of unlimited CO₂-fertilization, is only 18% of the 21st century SRES A2 scenarios emissions from India. The limited uptake potential of the natural potential vegetation suggests that reduction of CO₂ emissions and afforestation programs should be top priorities.     

Impact of climate change on Indian forests: a dynamic vegetation modeling approach

We make an assessment of the impact of projected climate change on forest ecosystems in India. This assessment is based on climate projections of the Regional Climate Model of the Hadley Centre (HadRM3) and the dynamic global vegetation model IBIS for A2 and B2 scenarios. According to the model projections, 39% of forest grids are likely to undergo vegetation type change under the A2 scenario and 34% under the B2 scenario by the end of this century. However, in many forest dominant states such as Chattisgarh, Karnataka and Andhra Pradesh up to 73%, 67% and 62% of forested grids are projected to undergo change. Net Primary Productivity (NPP) is projected to increase by 68.8% and 51.2% under the A2 and B2 scenarios, respectively, and soil organic carbon (SOC) by 37.5% for A2 and 30.2% for B2 scenario. Based on the dynamic global vegetation modeling, we present a forest vulnerability index for India which is based on the observed datasets of forest density, forest biodiversity as well as model predicted vegetation type shift estimates for forested grids. The vulnerability index suggests that upper Himalayas, northern and central parts of Western Ghats and parts of central India are most vulnerable to projected impacts of climate change, while Northeastern forests are more resilient. Thus our study points to the need for developing and implementing adaptation strategies to reduce vulnerability of forests to projected climate change.     

Budget-Balancing Incentive Mechanisms

A. P. Xepapadeas [J. Environ. Econom. Management20, 113-26, 1991] developed a pollution abatement incentive mechanism that both reduces the information requirements of a regulator and is "budget-balancing," drawing only on the social gains from pollution abatement to encourage firm compliance. This paper demonstrates that, contrary to Xepapadeas, the budget-balancing system of random penalties cannot be used to induce compliance with the regulator′s objectives if firms are risk neutral. However, the mechanism can be successfully applied if firms are sufficiently risk averse [E. Rasmusen, RAND J. Econom.18, 428-435, 1987].     

Organopesticides and fertility: where does the link lead to?

Environmental Science and Pollution Research - Organopesticides (OPs) are a group of various synthetic chemicals prevalently used in agriculture and homestead plantations. OPs were originally...     

Threat of heavy metal pollution in halophytic and mangrove plants of Tamil Nadu, India

Mangrove and halophytic plants occur along the coastal areas of Tamil Nadu, south India and these plants have been used in traditional medicine for centuries. Heavy metals are known to pose a potential threat to terrestrial and aquatic biota. However, little is known on the toxic levels of heavy metals found in mangrove and halophytic plants that are used in traditional medicine in India. To understand heavy metal toxicity, we investigated the bioconcentration factors (BCF) of heavy metals in leaves collected from eight mangroves and five halophytes in the protected Pichavaram mangrove forest reserve in Tamil Nadu State, south India. Data presented in this paper describe the impact of essential (Cu, Fe, Mg, Mn and Zn) and non-essential/environmentally toxic trace metals (Hg, Pb and Sn) in mangrove and halophytic medicinal plants. The concentrations of Pb among 13 plant species were higher than the normal range of contamination reported for plants. The average concentration of Hg in the halophytic plants (0.43+/-0.37mug/g) was seven times higher than mangrove plants (0.06+/-0.03mug/g) and it indicated pollutants from industrial sources affecting halophytes more than mangroves.     

ECONOMIC IMPLICATIONS OF PHOSPHORUS LOADING POLICIES FOR PASTURE LAND APPLICATIONS OF POULTRY LITTER1

ABSTRACT: Non-point source pollution created by agriculture is one of the major issues of intensive production. Recent studies indicate that the eutrophication from agricultural non-point source pollution, especially from phosphorus, is of growing concern. The objectives of this paper are to measure the economic opportunity costs of a proposed phosphorus management policy that targets soils with elevated phosphorus levels and examine the impacts of alternative policies such as Pigouvian taxes on the optimal use of litter. The study focuses on land applications of poultry litter in the Muddy Fork watershed of the Illinois River in Northwest Arkansas. The analysis indicates that restriction of litter applications on soils with elevated phosphorus levels will significantly reduce the net returns generated from forage production, resulting in an environmental policy with a high opportunity cost for producers. An analysis of alternative Pigouvian tax policies shows that a smaller tax per ton of litter applied can achieve the same litter control as that of a larger tax on a per acre basis.     

Histopathological studies and oxidative stress of synthesized silver nanoparticles in Mozambique tilapia (Oreochromis mossambicus)

To evaluate the potential environmental effects of engineered nano metals, it is important to determine the adverse effects of various nanomaterials on aquatic species. Adult tilapia (Oreochromis mossambicus) were maintained in 10 L glass aquaria, and exposed to a graded series of synthesized silver nanoparticles (Ag-NPs) at 25, 50 and 75 mg/L for eight days. The LC₅₀ value was 12.6 mg/L. Reduced activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with Ag-NPs, which resulted in heavy accumulation of free radicals. Histopathological results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs exposure. The principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles.