I suspect that the water cycle dominates. Check with Texas.
Back of the envelope calculation using the numbers from the Wikipedia articles on water cycle and biomass (ecology)
The turnover time is the time to run all the water in the physical water cycle through the biological water cycle.
Notation as in Fortran: 1E6 = 106 = 1 million
Total volume of water on earth = 1386E6 km3 = 1.4E24 grams
Annual biomass production = 1E11 tonnes carbon/year = 1.5E17 grams water/year
assuming biomass is CH2O, that is, biomass is cellulose but ignoring the one water molecule released per glucose when glucose is polymerized to cellulose. This factor isn't important given how rough the estimate of annual biomass production is likely to be.
So the turnover time for water is (1.4E24 grams water)/(1.2E17 grams water/year) = 1E7 years = 10 million years
So 6 or 7 turnovers since the last dinosaur peed in the drinking water (K-T extinction 66 million years ago)
</nerd>