And quality of organic matter

Schnitzer, M., McArthur, D. F. E., Schulten, FI.-R., Kozak, L. M., and Fluang, P. M. (2005). Long-term cultivation effects on the quantity and quality of organic matter in selected Canadian prairie soils. Geoderma 130,141-156. 

The quantity of litter input provides the second critical link between NPP and decomposition because NPP governs the quantity of organic matter inputs to decomposers. When biomes are compared at steady state, heterotrophic respiration (i.e., the carbon released by processing of dead plant material by decomposer organisms and animals) is approximately equal to NPP. In other words, net ecosystem production (NEP), the rate of net carbon sequestration, is approximately zero at steady state, regardless of climate or ecosystem type. This indicates that the quantity and quality of organic matter inputs to soils, as determined by... 

The quantity and quality of organic matter preserved during diagenesis of sediment determines the generative potential of the source rock and whether it will be prone to expel oil or gas. Quantity is determined by amount of organic input, the degree to which it is preserved (either as primary or... 

A variety of molecular indicators of the freshness (and perhaps nutritional quality) of organic matter exists. For example, certain labile phytoplankton constituents, such as polyunsaturated fatty acids, are readily degraded in the environment or in herbivore guts, and are thus depleted in more degraded particles (de Baar et ak, 1983 Wakeham and Canuel, 1988). Preferential loss of labile algal fatty acids resulting in the enrichment of more stable components in the products of heterotrophic metabolism has been observed in both field studies and laboratory feeding experiments (Prahl et ak, 1985 Wakeham and Canuel, 1988 Harvey et ak,... 

Sulfate reduction occurs mainly in sediments, with rates controlled by the quality and quantity of organic matter, S042- availability, bioturbation, abundance of dissolved O2 in overlying waters, rates of sulfide reoxidation, and availability of iron-sulfide minerals. 

The amount and quahty of the organic matter dehvered to the sediment surface will determine the amount and form of the N remineralized from the sediment (e.g., Lomstein et al., 1989). A number of studies have shown a positive correlation between increases in OM dehvery to the sediment and N regeneration (Enoksson, 1993 Jensen et al., 1990 Sloth et al., 1995 Therkildsen et al., 1996 Tyler et al., 2001). The quality of organic matter is also important. For example, phytoplankton detritus would be expected to have a much lower C N ratio than seagrass detritus or organic matter transported from the terrestrial environment (e.g., Enriquez et al., 1993), such that more N regeneration would hkely occur as a result of phytoplankton detrital deposition relative to deposition of seagrass detritus. 

Lapping critical water quality indices in real time is necessary for the development and verification of realistic mathematical models of the ocean. The advent of automated chemical analyses and computer mapping (1-4) has made real-time mapping of static chemical properties a reality. But these static properties, for example, nutrient salts, chlorophyll, and salinity, are not sufficient to describe the state of a system, nor can they be used to predict the recovery of a perturbed system. The dynamic properties, especially those that control the remineralization and oxidation of organic matter to CO2 and NO3, namely oxygen consumption, denitrification, and nitrification, must be measured (5-8). These processes are... 

Not only the quantity but also the quality of organic matter has been shown to influence bioavailability (Karickhoff et al., 1979). Sediment organic carbon provides a primary food source for benthic organisms. DeWitt et al. (1992) found that sediment pore water partitioning and toxicity of fluoranthene to the amphipod, Rheopyxinius abronius, were affected by sediment organic matter quality. 

The quality and quantity of organic matter inputs interact to drive soil metabolic activity (Zak et ai, 1994). Hence, annual soil... 

Inthorn, M., Wagner, T., Scheeder, G. and Zabel, M., subm. b. Lateral transport controls distribution, quality and burial of organic matter along continental slopes in high-productivity areas.- subm. to Geology. 

The amount of biogenic methane is essentially controlled by both the availability and reactivity of organic matter in the upper hundreds of meters of the sedimentary sequence. Davie and Buffett (2001, 2003) demonstrated the critical need for quantitative models of biogenic methane production to describe the distribution of gas hydrate in the top few hundred meters of sediment. Key parameters are rates of sedimentation, quality and quantity of the organic matter and biological activity rates. They show that hydrate accumulation from in situ production in sediment with a TOC of 1.5%, will be less than 7% of the pore volume... 

Crop rotation bears a close relationship to the title of this book since the crops grown, and the disposal made of them, affect the quality and quantity of organic matter in soils, and the extent of disease control. Nevertheless, the subject is in a sense a side issue and involves such a mass of research that no attempt will be made here to discuss it at length. Fortunately, Curl (1963), in a 67-page paper with 479 references has done an excellent job of assembling and analyzing the data. In addition, Kincaid (1960) has reviewed the information on the diseases of tobacco and states that some of those caused by nematodes, fungi, bacteria and viruses are amenable to control by crop rotation. 

Soil organic matter — humus — is a major determinant in soil health. A living system, soil is in continuous change, as new organic matter breaks down from the action of bioactivity, the insects, worms and micro-organisms that live in healthy soil. The amount of this activity and the quality of organic matter in soil depends upon the biomass added — food for the soil — a natural process. 

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