نتایج جستجو برای: particulate organic matter
تعداد نتایج: 403014 فیلتر نتایج به سال:
Secondary organic aerosol (SOA) constitutes a substantial fraction of fine particulate matter and has important impacts on climate and human health. The extent to which human activities alter SOA formation from biogenic emissions in the atmosphere is largely undetermined. Here, we present direct observational evidence on the magnitude of anthropogenic influence on biogenic SOA formation based o...
Although the principal source of marine organic matter is phytoplankton, experimental data on carbon and nitrogen mass balance during their growth cycle are lacking. Phytoplankton from diverse taxonomic groups (Synechococcus bacillaris, Phaeocystis sp., Emiliania huxleyi, Skeletonema costatum) were grown in synthetic seawater media, and changes in particulate and dissolved carbon, nitrogen, and...
Fine particles (PM2.5, i.e., particles with an aerodynamic diameter of ≤2.5μm) were collected from the air in August 2005, August–September 2006, and January– February 2007, in Beijing, China. The chemical compositions of particulate organic matter in the ambient samples were quantified by gas chromatography/mass spectrometry. The dominant compounds identified in summertime were n-alkanoic acid...
The ‘scope for growth’ (SFG) tool was used to study the growth performance of cultivated populations of Mytilus galloprovincialis (Lmk., 1819) in an oligotrophic area of the Southern Mediterranean Sea. The study was carried out between 1993 and 1996 by using data from four seasonal oceanographic cruises and from growth experiments. Water samples were collected and analysed for total suspended m...
We used 49,6-diamidino-2-phenylindole (DAPI) staining and fluorescent in situ hybridization to examine total bacterioplankton and archaeal distributions in surface waters and in deeper nepheloid layers and particle-poor waters across the Beaufort Shelf of the Canadian Arctic, including the Mackenzie River and Kugmallit Bay, as well as more distant Franklin Bay. Although the regional distributio...
Airborne particulate matter along with volatile organic compounds, heavy metals, and other compounds have raised many concerns to many countries including Iran. In this study, the concentrations of seven heavy metals (Cd, Cr, Co, Ni, Pb, Zn, and Al) associated with PM10 have been investigated during normal and dusty days from September to February 2012. The mean PM10 concentrations on the norma...
Port Curtis in central Queensland, Australia, is a large subtropical embayment with very extensive intertidal and shallow subtidal mudflats. Many economically important fish and crustacean species occur over mudflats lacking conspicuous vegetation. The autotrophic source(s) supporting food webs leading to animal production on the mudflats might be either in situ microalgae or material transport...
The riverine transport of particulate organic matter (POM) is a significant flux in the carbon cycle, and affects macronutrients and contaminants. We used radiocarbon to characterise POM at 9 riverine sites of four UK catchments (Avon, Conwy, Dee, Ribble) over a one-year period. High-discharge samples were collected on three or four occasions at each site. Suspended particulate matter (SPM) was...
The glaciations of the Neoproterozoic Era (1,000 to 542 MyBP) were preceded by dramatically light C isotopic excursions preserved in preglacial deposits. Standard explanations of these excursions involve remineralization of isotopically light organic matter and imply strong enhancement of atmospheric CO(2) greenhouse gas concentration, apparently inconsistent with the glaciations that followed....
Different hydrodynamic conditions can affect both the origin and the quality of organic matter available to bivalve molluscs. I chose 2 environments with very different hydrodynamics (a Mediterranean lagoon open to flow and a closed pond), but similar with regard to temperature, salinity, depth, wind exposure and algae coverage, to investigate this. The lagoon was characterised by active flow a...
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