Particulate organic matter, POM

Particulate organic matter (POM) in the ocean originates largely from plankton in the euphotic zone and reflects living plankton populations. Between 40°N and 40°S... 

The samples were analyzed for trace metals and sulfate as well as for three fractions of particulate organic matter (POM) using sequential extraction with cyclohexane (CYC), dichloromethane (DCM) and acetone (ACE). Factor analysis was used to identify the principal types of emission sources and select source tracers. Using the selected source tracers, models were developed of the form POM = a(V) + b(Pb) + - - -, where a and b are regression coefficients determined from ambient data adjusted to constant dispersion conditions. The models for CYC and ACE together, which constitute 90% of the POM, indicate that 40% (3.0 pg/m ) of the mass was associated with oil-burning, 19% (1.4 pg/m ) was from automotive and related sources and 15% (1.1 pg/m ) was associated with soil-like particles. 

Although the ultimate source of much of particulate organic matter (POM) in the urban aerosol appears to be fossil fuel a specific knowledge of the amounts and classes of organic compounds contributed by various types of sources is lacking. Estimates of source contributions have been based on emission inventories which have been largely directed toward polycyclic aromatic hydrocarbons and/or benzo(a)pyrene. There has been very little work on the development of mathematical and statistical models for POM source identification and allocation (1). In view... 

The degree of 15N enrichment between particulate organic matter (POM) and consumers can be used to accurately estimate trophic level (47, 49). Thus isotopic studies permit identification of consumer groups that form nutritional guilds via 13C and analyses, while establishing trophic-level interactions within these groups via 15N analyses. To date, very few combined 13C and 15N analyses of trophic structure in freshwater systems have been published (47, 50-52). 

The bioreactive fraction of particulate organic matter (POM) in 13 major rivers was characterized based on hydrolyzable neutral sugar and amino acid yields (Ittekot, 1988), and the relationship between the yields of... 

Physical protection is exerted by occlusion of particulate organic matter (POM) inside aggregates. It is responsible for the physical separation of organisms active in decomposition and substrates, reduced oxygen availability in the substrate compartment, and reduced biomass turnover through protection from microbial grazers (Mamilov and Dilly, 2002). 

Formation of aggregates, which allows inclusion of particulate organic matter (POM), thereby making it inaccessible to decomposing microorganisms, is a fundamental process in C sequestration. Besides the action of the soil macrofauna (already mentioned in Section 5.2), which aids in aggregate formation by reducing the size... 

Sannigrahi et al. (2005) analyzed 11 DOM samples and five samples of particulate organic matter (POM 0.1-60 pm) that were isolated from seawater using tangential-... 

Figure 9.17 Distribution of major fatty acids ( xg fatty acids L-1 and xg fatty acid mg-1 OC) in particulate organic matter (POM), very high molecular mass dissolved organic matter (VHDOM) (30 kDa-0.02 xm), and high molecular mass DOM (HDOM) (1-30 xm) in Delaware Bay estuary. Bacterial fatty acids (FA) included branched and normal saturated acids and 15 1A4 and PUFA = polyunsaturated fatty acids. (Modified from Mannino and Harvey, 1999.)...

The presence of organic matter (especially particulate organic matter, POM, common in seawater) promotes the coagulation of colloids by serving as binding material that favors their aggregation. Nevertheless, tidal movements re-suspend these settled... 

Schneider, B., Schhtzer, R., Fischer, G., and Nothig, E. M. (2003). Depth-dependent elemental compositions of particulate organic matter (pom) in the ocean. Global Biogeochem. Cycles 17(2), 1032, doi 10.1029/2002GB001871. 

Unlike DOC, which can be easily differentiated from dissolved inorganic C (DIC), DON is calculated by subtracting the concentrations of nitrate, nitrite, and ammonia from total dissolved N (TDN). This technique introduces several errors to estimates of DON concentration, and robust marine DON concentrations are a relatively recent phenomenon (Sharp et al., 2004). Methods for quantifying each of these N pools are discussed in McCarthy and Bronk (this volume). Contemporary studies often omit the filtration step that differentiates dissolved organic matter (DOM) from particulate organic matter (POM) because DOM is far more abundant even in surface waters. Therefore, reported concentrations often represent total organic N (TON) rather than simply the dissolved species. 

A schematic illustration of the food chain in the ocean indicating pathways of particulate organic matter (POM) and dissolved organic matter (DOM). The latter, indicated by the bold arrows in the figure, is called the microbial loop. 

If mean values calculated for the whole water column are compared, especially if the water depth is highly variable between the stations and the number of samples taken from various water layers is different, care must be taken with the interpretation of the results. For instance, mean concentrations of particulate organic matter (POM) calculated for all depths show a gradient (Fig. 12.12) with higher concentrations in the shallow western areas of the... 

Very volatile organic compounds and volatile organic compounds are transitory and predominantly found in air pesticides and other organic compounds with a low volatility or high polarity are either semivolatile organic compounds (SVOCs) or particulate organic matter (POM). 

Figure 14. A representation of the addition of particulate organic matter (POM) to. sediments. The amount of POM added increases from top to bottom. The frequency of POM addition increases from left to right. The amount of POM hydrolysis per day is 6, J6 or 60 mmol/rrp /day. Infrequent addition of POM will not support macrofaunal development and will result in POM hydrolysis at the. sediment surface (TOP distribution). whereas more frequent additions will results in increasing macrofaunal populations (LINEAR and MIX distributions) and greater sediment mixing. Dark shading repre.sents the degree of bioturbation (Fenchel et al, I99H).

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