Organisms heterotrophic

Carbon dioxide is produced as a result of metabolism of all heterotrophic organisms. The concentrations of CO2 in pore water of reduced sediments are therefore high. Autotrophic microorganisms consume CO2 in the oxidized part of the sediment, which can vary in depth from a meter in deep sea sediments to a few mm... 

This is not a reversible reaction in the strict sense and does not spontaneously seek equilibrium between products and reactants. The exothermic reverse reaction, respiration, occurs in a different part of phytoplankton cells or is mediated by heterotrophic organisms. 

Oceanic surface waters are efficiently stripped of nutrients by phytoplankton. If phytoplankton biomass was not reconverted into simple dissolved nutrients, the entire marine water column would be depleted in nutrients and growth would stop. But as we saw from the carbon balance presented earlier, more than 90% of the primary productivity is released back to the water column as a reverse RKR equation. This reverse reaction is called remineralization and is due to respiration. An important point is that while production via photosynthesis can only occur in surface waters, the remineralization by heterotrophic organisms can occur over the entire water column and in the underlying sediments. 

For the majority of redox enzymes, nicotinamide adenine dinucleotide [NAD(H)j and its respective phosphate [NADP(H)] are required. These cofactors are prohibitively expensive if used in stoichiometric amounts. Since it is only the oxidation state of the cofactor that changes during the reaction, it may be regenerated in situ by using a second redox reaction to allow it to re-enter the reaction cycle. Usually in the heterotrophic organism-catalyzed reduction, formate, glucose, and simple alcohols such as ethanol and 2-propanol are used to transform the... 

It is important to underscore the fact that carbon dioxide is required not only for the growth of strictly phototrophic and lithotrophic organisms. Many heterotrophic organisms that are heterotrophic have an obligate requirement for carbon dioxide for their growth. Illustrative examples include the following ... 

Kuzyakov Y, Larionova AA (2005) Root and rhizomicrobial respiration a review of approaches to estimate respiration by autotrophic and heterotrophic organisms in soil. J Plant Nutr Soil Sci 168 503-520... 

Heterotrophs Organisms that require organic matter as their carbon source. 

The term metabolism comprises the entire physical and chemical processes involved in the maintenance and reproduction of life in which nutrients are broken down to generate energy and to give simpler molecules (catabolism) which by themselves may be used to form more complex molecules (anabolism). In case of heterotrophic organisms, the energy evolving from catabolic processes is made available for use by the organism (IUPAC). 

Entropy is a state not only of energy but of matter. Aerobic (heterotrophic) organisms extract free en-... 

The factors that limit the formation of organic N from inorganic N are likely somewhat different for autotrophic and heterotrophic organisms (Fig. 1). Light can be an important limitation to most aquatic autotrophs (Sverdrup, 1953 Maclsaac and Dugdale, 1972 Cole and Cloern, 1984). On... 

In this chapter, we develop a simple model that predicts the maximum possible heterotrophic organic N formation as a function of the importance of allochthonous carbon inputs. We then review data from the literature on the relative importance of heterotrophic organic N formation in aquatic systems. This material is presented in a landscape context, following a flow path of organic matter from streams to the open ocean. We consider a variety of evidence to look at heterotrophic organic N formation, including enhancement of decomposition by N additions and ecosystem budgets. We rely, however, primarily on data from 15N addition studies to quantify the... 

TABLE I Importance of Heterotrophic Organic N (HON) Formation in Aquatic Systems... 

Where primary production is the sole source of organic matter for heterotrophic N formation, the maximum ratio of heterotrophic organic N (HON) formation to autotrophic organic N (AON) formation can be calculated from autotrophic production (AP), microbial heterotrophic production (MHP), and the C N ratios of autotrophs (C Naut) and microbial heterotrophs (C N ), such that... 

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