gtrestoration said:
Everyone else seems to be drinking something... maybe I do to.
I've read the thread but just see reference to being C limited. What if the C is dosed and maybe only N OR P, but not both are available. Would this C dosing still be effective in reducing the P OR N that IS available?
SteveU
Steve,
for heterotrophic aerobic bacteria C, N and O should be available following a certain ratio, which would be equivalent to the atomic ratio of these elements in the biomass.
Bacteria living in anoxic environemtns gain much less energy through anaerobic metabolism compared to aerobic bacteria. Thus, they grow/multiply much slower. Here, e.g. nitrate is majorily used as an electron acceptor in anaerobic metabolism. In aerobic bacteria, nitrogen is dominately used for nitrogen metabolism.
So, off course all these three major nutrients must be available, but you question cannot be answered that easy since we have both aerobic and anaerobic bacteria living in our tanks.
C-sources: I don't like sugars as C-sources as they are utilized by corals as well. The reason why e.g. Randy's corals turned brown after supplementing sugar is that coral metabolism is enhanced and this is coupled to both nitrogen ad phosphorus metabolism in these organism. So, increasing the nitrogen and phosphorus turnover in corals usually leads to an increase in zooxanthellae density, Same with host feeding.
If one adds sugars or better organic acids to the tank as coral organic nutrients the concentration of these compounds should be very low, otherwise it potentially leads to browing of corals.
Thus, as carbon sources for heterotrophic bacteria I'd prefer ethanol or methanol as these have been demonstrated to be easily utilized by bacteria but not by corals. In contrast, acetate as a carbon source for bacteria is also utilized by corals for fatty acid metabolism, so different organism are competing for this organic.
Concerning bacteria community structure:
In every ecosystem, so in reef tanks, the most competitive species will be dominating the organismal community in the ecosystem if the ecosystem's balance doesn't become disturbed. This is happening whether you dose a carbon source or not. So, while adding e.g. ethanol to reef tanks, one enhances the growth of those specimen which are most competitive under the given environmental conditions.
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