The main air pollutants are represented by gases forms, particles in suspension, different ionizing radiation and noise. The gases forms are: oxidized and reduced forms of carbon (CO 2 , CO, CH 4 ), of nitrogen (NO 2 , NO, N 2 O 4 , NH 3 , NH 4+ ), SO 2 , O 3 , C 6 H 6 vapours, Hg, volatile phenols, Cl 2 , etc. The particulate forms are: PM10 and PM2.5 particulate matter, heavy metals with toxic effect (Pb, Ni, Cd, As), polycyclic aromatic hydrocarbons PAHs, etc. Atmospheric pollutants have a negative effect on the plants; they can have direct toxic effects, or indirectly by changing soil pH followed by solubilization of toxic salts of metals like aluminum. The particulate matters have a negative mechanical effect. They cover the leaf blade reducing light penetration and blocking the opening of stomata. These impediments influence strongly the process of photosynthesis which rate declines sharply. Also the leaves of the trees have an important role in retention of the particulate matters; they are mostly affected when the wet and dry atmospheric deposition increase. The vegetation plays an important positive role in atmospheric purification and air pollutants reduction. The primary producers represented by plants are an important component in biogeochemical cycles. The vegetation made exchanges with a part of the atmospheric gases by photosynthesis, respiration processes, and the final stage of litter decomposition which mineralization. The plants play an important role in reducing atmospheric CO 2 content, by photosynthesis. This reduction of atmospheric CO 2 content has an important role in reducing of greenhouse gases, participating in reducing greenhouse effect and its consequences on climatic changes. The carbon stored in plants is the result of balance between carbon fixed by photosynthesis and carbon released in the atmosphere by respiration. As the structure of vegetation is more complex, the carbon stock in plants biomass is higher and the period of storage is longer. The most efficient type of vegetation in storing carbon in terms of carbon stored in plants alive is the temperate-continental forest; and in terms of carbon stored in dead organic matter are peat lands.
Rivers and their watersheds have been subject to various changes, including biodiversity, caused by anthropogenic activities. The Danube River and Black Sea basin overlap the geographic range of six species of anadromous fish belonging to the family Acipenseridae. Nowadays, they are endangered or at risk of extinction in the wild due to fragmentation and destruction of natural habitats, blocking their migration to spawning grounds, water pollution, and poaching. This paper presents a review of the historical and current distribution and evolution of the sturgeon populations of sturgeon species in the Danube River basin. Conservation status and measures for species protection, conservation, and restoration at the national, regional, and global levels are presented.
International audiencePredicting N2O (nitrous oxide) and CH4 (methane) emissions from peatlands is challenging because of the complex coaction of biogeochemical factors. This study uses data from a global soil and gas sampling campaign. The objective is to analyse N2O and CH4 emissions in terms of peat physical and chemical conditions. Our study areas were evenly distributed across the A, C and D climates of the Köppen classification. Gas measurements using static chambers, groundwater analysis and gas and peat sampling for further laboratory analysis have been conducted in 13 regions evenly distributed across the globe. In each study area at least two study sites were established. Each site featured at least three sampling plots, three replicate chambers and corresponding soil pits and one observation well per plot. Gas emissions were measured during 2–3 days in at least three sessions. A log-log linear function limits N2O emissions in relation to soil TIN (total inorganic nitrogen). The boundary line of N2O in terms of soil temperature is semilog linear. The closest representation of the relationship between N2O and soil moisture is a local regression curve with its optimum at 60–70 %. Semilog linear upper boundaries describe the effects of soil moisture and soil temperature to CH4 best.The global N2O boundary lines revealed a striking similarity with the Southern German N2O boundary lines, as well as with analogous scattergrams for Europe (Couwenberg et al. 2011) and Southern Queensland (Wang and Dalal 2010). This suggests that local rather than global conditions determine land-use-based greenhouse gas emissions.Further work will analyse relationships between the environmental factors and the spatial distribution of the main functional genes nirS, nirK and nosZ regulating the denitrification process in the soil samples currently stored in fridge at −18°. An additional analysis will study the relationships between the intensity of CH4 emissions and methanogenesis-regulating functional genes mcrA, pmoA and dsrAB
In Romania there are many types of historical oil soil contamination the most important beingthe land ones in Prahova County. The damage caused by this pollution may be permanent and takes a long time to remedied, sometimes requiring the ecological reconstruction of the polluted area. A major role in the remediation of soils polluted with oil plays the vegetation, some plant communities having a higher capacity to adapt and accelerate the process of mineralization of oil, hurrying decontamination. The goal of this paper was to realize an inventory of the oil-contaminated zones in Prahova County (historical oil pollution areas), to study the vegetation cover structure in selected representative sites and to identify potentially useful indicator species in terms of the ability to grow in extreme conditions for ecological restoration and remediate contaminated soils. Inventory of oil contaminated areas and historical data collection related to polluted areas and type of pollution were recorded. The vegetation studies have also been carried out in these areas. The richness of species in areas contaminated with oil is low (44 plant species-Tintea respectively 49-Pisculești, forming two different plant communities structure (Jaccard similarity index of about 1%) with low biomass production and productivity (338 DW/sqm). The number of nitrogen fixing plants is higher at Pisculeşti (6) compared to Ţintea (4) which can be explained by the fact that the nitrogen soil content at Pisculeşti is much less than at Ţintea. The conclusion was that the plants recommended for use in the reconstruction of historically polluted areas with oil, must have a genetic structure that enables them to adapt a high plasticity in terms of metabolism and root absorption, availability of absorption at radicular level in relation with chemical nitrogen forms. The most important are the plant species that develop the nitrogen fixation formations with different bacterial species.
Forest vegetation is a key factor in the maintenance of global carbon cycle balance under the present climate change conditions. Forest ecosystems are both buffers against extreme climatic events accompanying climate change and carbon sinks diminishing the environmental impact of anthropogenic greenhouse gas emissions. We investigated the influence of stand structure and site characteristics on the productivity and carbon storage capacity of temperate forest types. Predictors of species productivity were parameters such as stand density, age, height, average diameter and wood density. Morus alba (L.) was more productive than average both in terms of annual volume increment and annual biomass gain, while Quercus sessiliflora (Matt.) Lieb. and Quercus frainetto (Ten.) were significantly less productive than average. Differences in stand productivity were explained by stand density, age, height, altitude, type of regeneration and species composition. Statistically significant differences were measured between the productivity of stands dominated by different woody species, with low productive stands dominated by slow growing species with high wood density like Quercus or Fagus, and highly productive stands rich in fast growing species with low wood density like Populus or Salix. Stands with different plant communities in the underlying herbaceous layer also tended to have different levels of productivity.
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