RESEARCH: Issues Related to Greenhouse Effect,Productivity Modeling,and Nutrient Cycling: A Case Study of Indian Wetlands

/ Models available in the literature on nutrient uptake, lightavailability, and chlorophyll growth have been suitably modified andintegrated through the computer program CHLORF (written in "C"language), which has the advantage of being amenable to simulation undervarious combinations of input variables. The model has been used forsensitivity analysis in order to identify the most sensitive set ofparameters whose control can form an appropriate basis for evolving pragmaticmanagement strategies. In addition, greenhouse mitigation potential has beencomputed in terms of assimilation of carbon dioxide for a case study ofIndian wetlands.KEY WORDS: Wetland; Nutrient cycling; Modeling; Greenhouse effect     

Ghana: revival of the mineral sector

After almost two decades of decline, Ghana's mineral sector has rebounded significantly and is currently the main foreign exchange earner. Gold mining is the principal activity within the sector and accounted for 41 percent of total export earnings in 1996. This paper presents an overview of Ghana's mineral industry and covers mineral resources, production and reserves; mining investments; the role of mining in the economy; and the structure of the industry. An overview of the national mineral policy is also presented to depict the current regulatory and fiscal environment in which the industry operates. The spectacular reversal in mineral sector performance can be attributed to the adoption of World Bank recommendations in a new national mineral policy, the 1986 Minerals and Mining Law, aimed at revitalizing the sector.     

Influences of natural and anthropogenic processes on the nitrogen and phosphorus fluxes of the Yangtze Estuary, China

Nutrient flux to the sea through the estuary is important to the health of the sea. Combining natural processes with anthropogenic activities, we discuss the influence on the nitrogen and phosphorus fluxes to the Yangtze River basin, to the estuary and to the sea. The fluxes of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) to the estuary through the river/estuary interface are obviously higher than those to the sea through to the estuary/sea interface of the Yangtze estuary. The changes in nutrient fluxes through different interfaces are largely due to the estuarine hydrological and biogeochemical processes. Household, livestock and agricultural runoff are major sources of nitrogen from human activities, and household and livestock contribute to an increase in the anthropogenic phosphorus. The fluxes of DIN and DIP from economic activities account for about one-third of DIN and DIP fluxes to the sea through the Yangtze estuary.     

Assessment of the state of vegetation and prognosis of its anthropogenic dynamics in specially protected nature areas on the basis of Phytoecological mapping

Methodological approaches to the construction of phytoecological maps are described regarding specially protected nature areas and their specific features. Such maps offer new possibilities for the assessment and analysis of current and predicted states of vegetation.     

Evaluation of the impact of forest reserves on harvesting costs and provincial revenues in ontario

The establishment of forest reserves for the benefit of other resources and other land uses in areas where timber harvesting is taking place constitutes a significant withdrawal of wood fiber annually in Ontario.This article reports on a case study carried out on a representative forest area in northern Ontario where the primary land use is timber extraction. The results projected to the whole province show that the direct cost to the provincial economy of removing these forest lands from timber production is of the order of $2.5 million annually.     

Nutrient fluxes in a eutrophic coastal Louisiana freshwater lake

Nitrogen and phosphorus cycling in a eutrophic Louisiana freshwater lake system (Lac des Allemands) was studied. Nutrients from runoff entering the lake, as well as sediment-interstitial and lake water nitrogen and phosphorus fractions, were measured seasonally. Sedimentation rates in the lake were determined using¹³⁷Cs dating.Phosphorus levels in the lake were found to be largely dependent on concentrations in the incoming bayou water from upland drainage. Lake water concentrations appear to respond to fluctuations in incoming waters. Laboratory equilibrium studies showed bottom sediments in the lake are a major sink for the incoming dissolved orthophosphate phosphorus. Total nitrogen concentrations in the lake water generally exceeded incoming runoff concentrations, suggesting fixation by the large blue-green algae population in the lake as being the major source of nitrogen to the system.Sedimentation ranged from 0.44 cm/year to 0.81 cm/year, depending on the proximity to the inlet bayous. Even though the lake is eutrophic the sediment served as a buffer by removing large amounts of carbon, nitrogen, and phosphorus through sedimentation processes. Carbon, nitrogen, and phosphorus were accumulating in the sediment at rates of 60, 7.1, and 1.1 g/m²/year, respectively.The water quality of the lake is likely to continue to decline unless measures are taken to reduce municipal, industrial, and agricultural inputs of phosphorus into the lake.     

Pollen dispersal and intensity as criteria for the minimum viable population and species reserves

In small populations the lack of mating individuals may cause a reduction in reproductive potential which can restrict population expansion or cause further population declines. This is especially true in outcrossing monoecious and self-incompatible dioecious plant species. Principles of pollen dispersal suggest that many small to medium size population reserves of round shape will maximize the pollen interaction within and between island reserves. Diverse and low-density ecosystems require more total area in reserves than low-diversity and high-density ecosystems.