Compared with likelihood, Bayesian phylogenetic inference can be as or more robust to relative branch-length differences for datasets of this size, particularly when among-sites rate variation is modeled using a gamma distribution.
We applied lumped parameter models using a gamma distribution to calculate the Mean Transit Time (MTT) of water over the entire period of record and to evaluate how inter-annual differences in transit times relate to hydroclimatic variability.
In the second case, the histogram is modelled using a Gamma distribution function where the 90% cumulative interval provides the threshold.
Trees were reconstructed by maximum likelihood using a gamma distribution with four rate categories and coefficients of variation (base frequencies, transition/transversion ratio, rates of change and gamma distribution shape parameter) estimated from the data using the DNAML programme.
NJ was performed in Mega 4 [29] using a gamma distribution of among site substitution rates (0.66, as estimated by PhyML), the Poisson correction model and 5000 bootstrap replicates.
Rate variation across sites was modeled using a gamma distribution.
A generalized linear model using a gamma distribution was used to control for these differences.
Rate variation across sites was modelled using a gamma distribution (rates = "gamma").
Therefore, a generalised linear model was fitted using a gamma distribution and log-link function.
Rate variation across sites was modelled using a gamma distribution (rates = "invgamma").
