[R-sig-eco] Q10

[Stephen Sefick]

linearize the model and fit.

I think it is
lny=lna+bx

make sure I did the conversion correctly

y=ae^bx

take the natural log of both sides

ln(y)=ln(ae^bx)

ln(y)=a+ln(e^1)*bx

ln(y)=a +bx

Hopefully I did this right,

Stephen


On 01/30/2012 10:01 AM, Alan Haynes wrote:
> Dear Ecology list,
>
> I'm trying to calculate the Q10 (temperature sensitivity) of decomposition
> in R. I have done so in excel straight forwardly enough but I want to check
> it in R.
> Does anyone have any ideas how to go about this?
>
> It is calculated as
>
> y_T ~ a * e^(bx_T)
> where y is the decomposition rate at temperature T, x_T is the temperature
> and "a" and "b" are constants. "e" is the magic number (exp(1) ; 2.7183)
>
> then
>
>   Q10 = exp(10*b)
>
> In excel I simply fit an exponential trend line, read off "b" from the
> formula and then calculate Q10 as above. In R it seems to be a bit harder.
>
> Ive attempted to use nls() to derive the exponent but I get a completely
> different number (when it doesnt give me a singularity error). nls() doesnt
> seem to like the "a" term either, as it seems to be this that generates the
> singularity issue.
>
> Does anyone know of a function, or suite of functions, for calculating Q10?
>
> Thanks in advance,
>
> Alan
>
>
>
> --------------------------------------------------
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-- 
Stephen Sefick
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