نتایج جستجو برای: organic carbon
تعداد نتایج: 452157 فیلتر نتایج به سال:
Soil sequesters large amounts of carbon derived from organic and inorganic sources. Soil organic carbon (SOC) has to be measured periodically for the study of climate change. Many methods are used to estimate SOC and those methods are relatively time consuming and costly, with carbon in soil samples converted to carbon dioxide which is then measured directly or indirectly by different methods. ...
To establish the influence of phytoplankton blooms on the cycling of dissolved and particulate species of organic carbon and nitrogen, we conducted a field study during a series of blooms in a coastal embayment on Shelter Island, NY. Using cross-flow filtration, we collected highand low-molecular-weight (HMW and LMW) dissolved organic matter (DOM), along with particulate organic matter (POM). T...
We report measurements of oceanic black carbon (BC) to determine the sources of BC to abyssal marine sediments in the northeast Pacific Ocean. We find that the average C age of BC is older (by 6200±2200 C years) than that of the concurrently deposited non-BC sedimentary organic carbon. We investigate sources of aged BC to sediments by measuring a sample of sinking particulate organic carbon (PO...
[1] Reconstructing the dissolved carbon dioxide of surface waters from the dC of organic carbon relies on accurate determination of the growth rate of phytoplankton contributing to sedimentary organic matter. We demonstrate that the Sr/Ca ratio in the coccoliths of Emiliania huxleyi is correlated with the rates of both organic carbon fixation and calcification. An investigation of biomineraliza...
Livestock grazing is one of the most important kinds of land usage that has a high potential to decrease or increase carbon storage in rangeland ecosystem. This research was investigated the effects of enclosure on soil carbon storage in a rangeland with dominant plants of Artemisia aucheri. Hence, two rangelands of enclosure (Shahtappeh-Chah Mahmood) and no enclosure (Chiro) were chosen in Sem...
Sequestration and diffusion of three polycyclic aromatic hydrocarbons (PAHs) in seven Chinese soils were investigated for up to 200 days in sterile soil microcosms as functions of soil property and aging time. The aging of the PAHs, assessed using a mild extractant that removes primarily the labile fraction, showed a biphasic behavior. The rapid diffusion from labile to nonlabile domains was ma...
A detailed understanding of the sources, transformations and fates of organic species in the environment is crucial because of the central roles that they play in human health, biogeochemical cycles and the Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at ...
Organic carbon is present in all natural waters and plays an important role in many geochemical processes. Total organic carbon (TOC), measured on unfiltered samples, has been analysed on more than 400 groundwater samples from 8 European Union countries, and the operationally defined dissolved organic carbon (DOC), measured on filtered samples, was analysed on approximately 250 groundwater samp...
Solubility and Leaching Risks of Organic Carbon in Paddy Soils as Affected by Irrigation Managements
Influence of nonflooding controlled irrigation (NFI) on solubility and leaching risk of soil organic carbon (SOC) were investigated. Compared with flooding irrigation (FI) paddies, soil water extractable organic carbon (WEOC) and dissolved organic carbon (DOC) in NFI paddies increased in surface soil but decreased in deep soil. The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 4...
The losses of benzoic acid and a homologous series of both mono- and dibasic aliphatic acids in oil shale retort water were monitored with time (21 days) in liquid culture (4% retort water, vol/vol) inoculated with soil. The organic acids constituted approximately 12% of the dissolved organic carbon in retort water, which served as the sole source of carbon and energy in these studies. The leve...
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