نتایج جستجو برای: 11 geochemical tracers including oc organic carbon
تعداد نتایج: 1735166 فیلتر نتایج به سال:
Secondary organic carbon (SOC) formation and its effects on human health require better understanding in Chinese megacities characterized by a severe particulate OPEN ACCESS Atmosphere 2015, 6 362 pollution and robust economic reform. This study investigated organic carbon (OC) and elemental carbon (EC) in PM2.5 and PM0.25 collected 8–20 March 2012. Samples were collected inside and outside a c...
We examined variations in organic carbon (OC) pools and microplanktonic carbon fluxes at three stations in the Hudson River estuary during 12 cruises between Octobers of 1996 and 1998. Phytoplankton biomass and net primary production varied from 5 to 40 mmol C L21 and 0.3 to 318.3 mmol C m22 d21, respectively. Biomass and production of bacterioplankton in the surface layer commonly exceeded tho...
The Leg 104 organic geochemistry program consisted of monitoring (a) hydrocarbon gases, (b) organic and inorganic carbon, and (c) parameters resulting from Rock-Eval pyrolysis at three sites on the Vdring Plateau. The results amplify some of those obtained earlier on Deep Sea Drilling Project (DSDP) Leg 38. In a regional sense there is an inverse correlation between amounts of hydrocarbon gas a...
While several studies have investigated wintertime air pollution with a wide range of concentration levels, hardly any results are available for longer time periods covering several winter-smog episodes at various locations; e.g., often only a few weeks from a single winter are investigated. Here, we present source apportionment results of winter-smog episodes from 16 air pollution monitoring s...
Partitioning and source diagnostics of polycyclic aromatic hydrocarbons in rivers in Tianjin, China.
Water, suspended particulate matter (SPM), and sediment samples were collected from ten rivers in Tianjin and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), dissolved organic carbon (DOC), particulate organic carbon (POC) in SPM and total organic carbon (TOC) in sediment. The behavior and fate of PAHs influenced by these parameters were examined. Generally, organic carbon was the prim...
Air-starved combustion of biomass and fossil fuels releases aerosols, including airborne carbonaceous particles, causing negative climatic and health effects. Radiocarbon analysis of the elemental carbon (EC) fraction can help apportion sources of its emission, which is greatly constrained by the challenges in isolation of EC from organic compounds in atmospheric aerosols. The isolation of EC u...
Earth System Models increasingly include ocean biogeochemistry models in order to predict changes in ocean carbon storage, hypoxia, and biological productivity under climate change. However, state-of-the-art ocean biogeochemical models include many advected tracers, that significantly increase the computational resources required, forcing a trade-off with spatial resolution. Here, we compare a ...
Iron (Fe)-rich colloids in the environment have a high surface reactivity and facilitate transport of oxyanions trace metal cations soil. This study was set up to help identify soil properties that might affect concentrations colloidal Fe its size distribution pore waters soils. The water isolated by centrifugation from collection 97 topsoils with contrasting land use. total concentration range...
The bacteria and their phages are the most abundant constituents of the aquatic environment, and so represent an ideal model for studying carbon regulation in an aquatic system. The microbe-mediated interconversion of bioavailable organic carbon (OC) into dissolved organic carbon (DOC) by the microbial carbon pump (MCP) has been suggested to have the potential to revolutionize our view of carbo...
Total carbon (TC) is sometimes used to measure or characterize diesel particulate matter (DPM) in occupational settings such as underground mines. DPM samples are collected on quartz fiber filters. When using quartz fiber filters, adsorption of gas phase organic carbon (OC) has been reported, causing a positive bias in the particulate TC results (adsorption artifact). Most of the data on the sa...
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