نتایج جستجو برای: free particulate organic matter and intra
تعداد نتایج: 16984102 فیلتر نتایج به سال:
Weathering of K-bearing minerals as the major source of potassium in soils is of special importance under K deficient conditions. Many studies have been carried out on the effect of plant types and microorganisms on the transformation of micaeous minerals and their potassium release. However, there is no information on the effect of organic matter on mineralogical changes in micaceous minerals....
Soil organic matter dynamics in a North America tallgrass prairie after 9 yr of experimental warming
The influence of global warming on soil organic matter (SOM) dynamics in terrestrial ecosystems remains unclear. In this study, we combined soil fractionation with isotope analyses to examine SOM dynamics after nine years of experimental warming in a North America tallgrass prairie. Soil samples from the control plots and the warmed plots were separated into four aggregate sizes (>2000 μm, 250–...
As part of the Western Arctic Shelf–Basin Interactions (SBI) project, the production and fate of organic carbon and nitrogen from the Chukchi and Beaufort Sea shelves were investigated during spring (5 May–15 June) and summer (15 July–25 August) cruises in 2002. Seasonal observations of suspended particulate organic carbon (POC) and nitrogen (PON) and large-particle (453mm) size class suggest t...
Biological degradation of terrestrially derived macromolecules including lignin and cellulose has been shown to produce a large number of environmentally relevant phenolic compounds. It has demonstrated that extracellular superoxide (O2 ) is produced by heterotrophic bacteria that are common in lakes, soil, hydrothermal vents, marine sediments, estuaries and oceans. Rates of superoxide producti...
Cold-water corals release organic matter, in particular mucus, but its role in the ecological functioning of reef ecosystems is still poorly understood. The present study investigates the planktonic microbial degradation of mucus released by Lophelia pertusa colonies from Tisler Reef, Skagerrak. Results are compared to the degradation of dissolved and particulate organic substrates, including t...
The Tibetan Plateau reacts particularly sensitively to possible effects of climate change. Approximately two thirds of the total area is affected by permafrost. To get a better understanding of the role of permafrost on soil organic carbon pools and stocks, investigations were carried out including both discontinuous (site Huashixia, HUA) and continuous permafrost (site Wudaoliang, WUD). Three ...
Phosphorus (P) regeneration and transformation in the oceanic water column and in marine sediments depends on the chemical nature of the sinking particulate P pool. For the first time, we have characterized the molecular composition of this pool, in various oceanic settings and water depths, using P nuclear magnetic resonance (NMR) spectroscopy. Both inorganic P (orthophosphate, pyrophosphate, ...
backgrounds and objectives: the dispersion of particulate matter has been known as the most serious environmental pollution of cement plants. in the present work, dispersion of the particulate matter from stack of kerman cement plant was investigated using computational fluid dynamics (cfd) modeling.materials and methods: in order to study the dispersion of particulate matter from the stack, a ...
The relationship of bronchitic symptoms to ambient particulate matter and to particulate elemental and organic carbon (OC), nitrogen dioxide (NO2), and other gaseous pollutants was examined in a cohort of children with asthma in 12 Southern California communities. Symptoms, assessed yearly by questionnaire from 1996 to 1999, were associated with the yearly variability of particulate matter with...
Indoor air pollution is an increasing health concern, especially in enclosed environments such as underground subway stations because of increased global usage by urban populations. This study measured the indoor air quality of underground platforms at 10 metro stations of the Taipei Rapid Transit system (TRTS) in Taiwan, including humidity, temperature, carbon monoxide (CO), carbon dioxide (CO...
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