Biotic phase

It should be noted that even though concentration terms are expressed based on the total culture volume, kinetic parameters still remain on a biotic phase basis in the formulation. 

The cyclical movement of elements between living organisms (the biotic phase) and their nonliving (abiotic) surroundings (e.g. rocks, water, air). Examples of biogeochemical cycles are the carbon cycle, nitrogen cycle, oxygen cycle, phosphorus cycle, and sul-phur cycle. 

During the second biotic phase, smaller fragments are dissolved in extracellular fluids, where they are destroyed by phagocytes or metabolized by the cells. 

Most of the stirred-tank fermentations are aerobic and use oxygen, which is supplied as air. This presents a complex, multiphase setting, with gas, liquid, and solids (i.e., the biotic phase, and in some cases also solid substrates and products) existing together in the same space. Non-gassed stirred tanks are a minority. 

One important further extension will be to consider the biotic phase not as a continuum but as a community of segregated individual cells that all can have different phenotypes depending on their accumulated interactions with the environment. The cells can also be further structured based on their individual metabolic state. This will provide more realistic descriptions of the biotic phase,... 

Microwave extraction realized at 120 °C for 30 min with Hexane -Acetone (3 2 V/V) as the extraction solvent was identified as the most effective extraction procedure for isolation of TPH from biotic matrices. The aim of this research is to develop a silica gel and alumina fractionation procedure for plant sample extraction. Column chromatography with two solvents (chloroform and hexane dichloromethane) as a mobile phase were used for clean-up of extract. In this research the efficiency of recovery received from chloroform as a mobile phase. 

To which phase is the substance likely to migrate will a pesticide applied to soil leach or be volatile will a chemical accumulate in the biotic compartment and so on. 

It influences the distribution of substances between the aqueous phase and particulate matter, which, in turn, affects their transport through the various reservoirs of the earth. The affinity of the solutes to the surfaces of the "conveyor belt" of the settling inorganic and biotic particles in the ocean (and in lakes) regulate their (relative) residence time, their residual concentrations and their... 

This chapter is organized as follows We first attempt to discuss, in terms of simplified models, how particles carrying functional groups behave in solutions whose variables are known or controlled. This is followed by observations and interpretations on the concentration of trace elements in rivers and how these trace elements are distributed between particulate and dissolved phase. Then, we will consider the regulation of metal ions and of other reactive elements in lakes above all, it will be shown that the interaction of these trace elements with biotic and non-biotic particles and the subsequent settling of these particles will be of utmost importance for their removal from the water/column. Finally considerations will be given to inquire to what extent similar interpretations can be given to oceans. 

Sorption/desorption is the key property for estimating the mobility of organic pollutants in solid phases. There is a real need to predict such mobility at different aqueous-solid phase interfaces. Solid phase sorption influences the extent of pollutant volatilization from the solid phase surface, its lateral or vertical transport, and biotic or abiotic processes (e.g., biodegradation, bioavailability, hydrolysis, and photolysis). For instance, transport through a soil phase includes several processes such as bulk flow, dispersive flow, diffusion through macropores, and molecular diffusion. The transport rate of an organic pollutant depends mainly on the partitioning between the vapor, liquid, and solid phase of an aqueous-solid phase system. 

The abiotic characteristics of aqueous-solid phase interfaces strongly influence chemical/biochemical reactions in the interface microenvironment of aqueous-solid phases. These reactions at interfaces are controlled mainly by biotic activity. Specifically, all aqueous-solid phase microenvironments contain living microorganisms that mediate biochemical transformations. Solid phases (e.g., soil and sediment particles) usually contain billions of microorganisms, with the aqueous phase containing smaller, but still significant, populations [22,33-39]. 

The major groups of microorganisms at aqueous-solid phase interfaces include viruses, bacteria, fungi, algae, and macro fauna (e. g., protozoa and arthropods). All of these microorganisms have specific ecological niches and functions, and each contributes to the overall biotic activity of this microenvironment. 

In order to understand the factors that limit microbial activity in the microenvironments of aqueous-solid phase interfaces, it is necessary that biotic and abiotic factors be discussed. These factors include the following. 

The dynamics of oil-in-water dispersion (OWD) are complex and have relevance related to potential toxicity or hazard. In comparing the toxicides to marine animals of oil-in-water dispersions prepared from different oils, not only the amount of oil added but also the concentrations of oil in the aqueous phase and the composition and dispersion-forming characteristics of the parent oil must be taken into consideration. In comparing the potential impacts of spills of different oils on the marine biotic community, the amount of oil per unit water volume required to cause mortality is of greater importance than any other aspect of the crude oil behavior. 

Genuine hysteresis is considered when contaminant release results only from desorption. Experimental data can be interpreted in terms of genuine desorption only when the system is at equilibrium and released molecules are those adsorbed onto the solid phase surface. Molecules brought back into the solution as result of dissolution, diffusion out of the solid matrix, or biotic/abiotic transformation cannot be considered desorbed molecules. In the subsurface, it is almost impossible to distinguish between desorbed molecules and molecules that were not subjected to adsorption and desorption. 

The rate of methylation of mercury in anaerobically incubated estuarine sediments proved to be inversely related to salinity (267) this is consistent with results reported in Section II,A. Methylmercuric ion forms in sediments upon addition of HgCl2, with a lag phase of 1 month (268). Biomethylation by lake water columns and by sediments coincided, apparently being related to overall microbial activity, and showed periodic fluctuations (269). Topping and Davies have demonstrated that mercury can be methylated in the water column of a sea loch (270). As has previously been noted, tin compounds can be methylated by sediments (121-124), and this is also true for lead (134-136, 271). The relative proportions of biotic and abiotic methylation processes for such systems still remain to be determined. 

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