Biomass estimates indirect methods

A final optical application deals with the measurement of intracellular nicotinamide adenine dinucleotide (NADH) by fluorescence [77], giving information about the physiological status of wastewater treatment plant biomass. This indirect method could be envisaged for toxicity estimation. 

Measurement of soil activity there are a number of laboratory methods which are suitable for measuring the biological activity of the soil. In principle, a distinction is made between direct and indirect methods for the determination of soil activity. The biomass in the soil, for example, can be estimated by counting the individual organisms in the soil, or the measurement of respiration after the addition of a nutrient in excess can provide an indication of active biomass. Moreover, in determinations of activity, a distinction is made between actual and potential activity. Actual activity values are values measured at the time that the sample was taken. Determinations of potential activity, on the other hand, show the level of performance that microorganisms are capable of under optimum experimental conditions, after the addition of a nutrient substrate and prolonged incubation. 

Estimation methods for Amazonian forest biomass direct versus indirect methods... 

Forest biomass in the Amazon has been estimated through direct and indirect methods. Independent of the method used, one should take into consideration that all components of forest biomass must be quantified. Besides the trees that are the main component of the forest, other components to be included are vines Gianas), understory plants, litter, roots, palms, etc. 

Indirect methods, based on allometric inference, from measurements of the diameter at breast height (DBH) and the height of the trees to obtain wood volumes, is the main method adopted to estimate biomass in the Amazon. Forest biomass estimates are made through regression analysis, where several fitting curves are tested to obtain an ideal model that can be applied to the trees. These models are calibrated by direct weighing of the biomass from a subsample of trees (see for example, Jordan and Uhl 1978, Higuchi et al. 1994, Brown et al. 1995), and could also include other compartments besides trees, such as vines or understory. Indirect methods are broadly adopted in the forestry industry to evaluate the volume of commercial wood. 

Direct/indirect methods refers to the estimate of biomass by destructive harvest, supplemented for branches and trunks < 10 cm in diameter by indirect methods of line-intersect sampling. Used to estimate the biomass in areas of felled forest. 

Estimates through indirect methods should improve the regression equations to estimate the biomass of larger trees, which represent... 

To put the results of the stock assessments into the appropriate perspective and thus to help the interpretation, it is important to try to extend the knowledge on the state of the stocks further into the past, without the aid of fish stock assessments that provide the estimates. One source of data that reach further back than the assessments are the catches of the fishery from the official landings statistics. These have been compiled since the beginning of the twentieth century but have naturally some shortcomings. To circumvent this, the biomass of the fish in the Baltic was estimated back to the 1920s by using the available assessments and indirect methods (Thurow, 1997). 

Oxidative phosphorylation was also demonstrated by an indirect method, by estimating how much substrate was used for the synthesis of one unit of biomass (Ts) As shown in Table 3.10, the two species display maximal growth yield coefficients (Ys) under aerobic conditions of growth, therefore, in the presence of oxygen the substrate is utilized more effectively, especially by P. petersonii, which produces 2.5 times more ATP per unit substrate under aerobic conditions. In P. shermanii the difference is smaller, indicating that metabolic changes induced by the transition from anaerobic to aerobic conditions are less profound. 

The latter requirement and the concomitant improvement of comfort led to the exploitation of alternative methods to estimate the biomass concentration. All of them have in common (1) that they are indirect measures, and (2) that models are mandatory to relate these measures to biomass concentration. The models are of the descriptive rather than the mechanistic type which means... 

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