What's in your tank?

[ichthyoid]

While researching carbon dosing, I recently came across this text and was reminded of how much I have forgotten since school. It turns out that 50% of the dry weight of bacteria is carbon! Most bacteria cannot obtain carbon themselves, so require an organic source.

We don't add any in our salt, water or even food. The labels on my foods only mention protein, fats, fiber & moisture. No carbohydrate, which is a form of organic carbon.

As many of you know, carbon dosing using small amounts of vodka, sugar, vinegar, etc. is gaining in popularity, and the results on corals can be stunning!

Since bacteria are at the base of the food web in the ocean, I think it is important to not only understand their needs, but to provide for them as well. Carbon dosing does just that.

Without supplementing, carbon is a 'limiting factor' and most bacteria will not thrive in our systems. That effect trickles 'up' the food chain, IMO, causing us to exert great effort to sustain life in an aquarium.

Here is the link- http://www.textbookofbacteriology.net/nutgro.html">http://www.textbookofbacteriology.net/nutgro.html</a>
(there are also 5 additional pages, see bottom of the page)

Thoughts?

 

[stacy22]

Proteins, fiber and fats are also carbon rich. Fiber is a polysaccharide (complex carb). Proteins contain C, H, O, N, and S. Fats (lipids) are C, H, and O.

 

[ichthyoid]

stacy22;636080 wrote: Proteins, fiber and fats are also carbon rich. Fiber is a polysaccharide (complex carb). Proteins contain C, H, O, N, and S. Fats (lipids) are C, H, and O.

That is correct, there is carbon in the chains of these compounds. However after digestion by the fish, inverts, etc. it exists in a low energy (oxidized) form, such as CO2. That CO2 is unavailble to these heterotrphic bacteria. Also, the carbon in some fiber is unavailable to bacteria, as well. If it's been digested, there's not much organic carbon left.

The point here is that carbon is rate limiting in the marine environment. In nature phytoplankton supply considerable carbon via fixation in marine ecosystems. That source is essentially absent in the aquarium, as well.

 

[rbredding]

ichthyoid;636079 wrote:
As many of you know, carbon dosing using small amounts of vodka, sugar, vinegar, etc. is gaining in popularity

Biopellets... .

(I got my BRS order in the other day... we'll see.. )

 

[ichthyoid]

It has been suspected that different strains of bacteria can utilize different forms of carbohydrate. The link below is to a paper, apparently written some years ago, that shows this to not only be true, but that the concentration is critical as well (see table #1). Some strains use the carbon source better than others, and in a couple of cases cannot use certain types at all. This makes sense, since different strains certainly produce different enzymes and vary in their metabolisms.

Since this is the case, it could explain a lot in the way of the varying degree of success seen by different hobbyists that have tried carbon dosing. There are different forms of carbon including:
-methanol
-ethanol (vodka)
-glycerol
-sucrose (sugar)
-acetic acid (vinegar)
-lactose (milk sugar)
-polycraprolactone polymer beads (pellets)
and the list goes on............

It appears that we may need to consider a blend of carbon sources and that their actual concentrations are important as well.