Profile fitting data reduction

Data Reduction and Analysis For inhibition profiles, the means of triplicate data points (at individual inhibitor concentrations) were plotted. IC50 values were determined using either a log-logit or four parameter fit. (Correlation coefficients were determined from the best fit of these data.) Error bars representing standard deviations (SD) are only presented in selected inhibition profiles. Paraoxon equivalence (%), PE, was determined using the following relationship ... 

The coincidence of maxima in the methane oxidation rate and the sulfate reduction rate in Saanich Inlet strongly suggests that the methane oxidizing agent was sulfate, either via direct reaction, or coupled indirectly through reactions with other substrates (Devol, 1983). A methane-sulfate coupled reaction diffusion model was developed to describe the inverse relationship commonly observed between methane and sulfate concentrations in the pore waters of anoxic marine sediments. When fit to data from Saanich Inlet (B.C., Canada) and Skan Bay (Alaska), the model not only reproduces the observed methane and sulfate pore water concentration profiles but also accurately predicts the methane oxidation and sulfate reduction rates. In Saanich Inlet sediments, from 23 to 40% of the downward sulfate flux is consumed in methane oxidation while in Skan Bay this value is only about 12%. 

In general, the hollow cylinder or average microenvironment model fits the NH data extraordinarily well with only minor variation in rj, the effective density of animals. The required variation in r- presumably comes about because of the uneven distribution of animals within sediment (Jumars et al., 1977) and mobility. It may also be apparent variation due to the arbitrary requirement that r, remain fixed. The variation forced into r2 by this restriction could actually reflect changing boundary conditions at r, for example, inhibition to diffusion by burrow linings or a reduction in irrigation activity. A part of the discrepancy between the model and measured profiles could also reflect changes in the production rate of NH/ because of factors other than temperature. For example, fall profiles may show a smaller maximum than predicted, due to a lower reaction rate resulting from a depletion of substrate (see Nixon et al., 1980). 

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