Respirable particulate matter organic

Only 1.2% of the carbon of 2,4-D added to stream water was converted to organic particulate matter, the solids fraction in water containing the microbial cells. This lack of significant carbon assimilation may be a result of the inability of the microorganisms to obtain carbon and energy for biosynthetic purposes at these low concentrations, the immediate use of the carbon for respiration in order for the cells to maintain their viability (i. e., for maintenance energy), or the rapid decomposition and mineralization of the cells and their constituents. 

The average ambient concentrations of the cyclohexane-, di-chloromethane- and acetone-soluble organic fractions from January, 1978 to August, 1979 were 2.9 yg/m, 1.0 yg/m and 4.4 yg/m. Respirable suspended particulate matter averaged 30.3 yg/m. ... 

Multivariate source. apportionment models have been developed for two fractions of respirable particulate organic matter which together constitute about 90% of the total organic solvent-extractable mass. The independent variables used for developing the models were trace metals, water-soluble sulfate and meteorological variables. Two of the three POM fractions extracted sequentially with cyclohexane (CYC), dlchloromethane (DCM) and acetone (ACE) were used as individual dependent variables. 

Chemical Gases and vapours Particulate matter Inorganic NO, SO Organic volatile organic compounds, CO, formaldehyde Asbestos, respirable particles with a diameter less than 10 pm, particulate matter which is smaller than 10 pm... 

Neutron activation analysis is one of the major techniques for the determination of many minor and trace elements in a large variety of solid environmental and pollution samples, such as atmospheric aerosols, particulate emissions, fly ash, coal, incineration ash, and sewage sludge. Instrumental neutron activation analysis of total, inhal-able, or respirable airborne particulate matter collected on a cellulose or membrane filter, or in a cascade impactor on some organic substrate, allows the determination of up to 45 elements by an irradiation - counting scheme similar to the one given in Figure 3. Radiochemical NAA is applied only when extremely low limits of determination are required. Instrumental photon activation analysis is also complementary to INAA. 

Stelzer, R. S., Heffeman, J. Likens, G. E. (2003). The influence of dissolved nutrients and particulate organic matter quality on microbial respiration and biomass in a forest stream. Freshwater Biology, 48, 1925-37. 

Gerber, R. P., and Gerber, M. B. (1979). Ingestion of natural particulate organic matter and subsequent assimilation, respiration and growth by tropical lagoon zooplankton. Mar. Biol. 52, 33—43. 

In these examples as well as for most aquatic sediments, the principal diagenetic reactions that occur in these sediments are aerobic respiration and the reduction of Mn and Fe oxides. Under the slower sedimentation conditions in natural lakes and estuaries, there is sufficient time (years) for particulate organic matter to decompose and create a diagenetic environment where metal oxides may not be stable. When faster sedimentation prevails, such as in reservoirs, there is less time (months) for bacteria to perform their metabohc functions due to the fact that the organisms do not occupy a sediment layer for any length of time before a new sediment is added (Callender, 2000). Also, sedimentary organic matter in reservoir sediments is considerably more recalcitrant than that in natural lacustrine and estuarine sediments as reservoirs receive more terrestrial organic matter (Callender, 2000). 

Coral reef communities have also demonstrated the ability to take up suspended planktonic organic matter as a source of new carbon (Glynn, 1973 Johannes Gerber, 1974 Ayukai, 1995 Sebens etal., 1997 Fabricius etal., 1998 Ribes etal, 1998 Yahel etal., 1998). Reported rates of particulate carbon uptake are low (<40 mmol Cm-2 day-1) compared to rates of gross primary production and community respiration (Table 2.2), and have been demonstrated to be an unimportant source of carbon for some hard and soft coral communities (Ribes, 1998 submitted). However, the uptake of particulate organic matter may be an important source of food for some specific reef communities (Fabricius etal., 1998). 

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