Adding Organic Carbon do reduce DOC. contradictory..!?

[Dan Reef]

Hello reefers!

Julian Sprung was recently in Brazil and did a nice speech about DOC.

In one of his slides, he suggest means to reduce it. One is dosing organic carbon.

It seems contraditory but so does algae refugium/ reactor as algae also release DOC.

What do you think?

 

[Randy Holmes-Farley Verified Community Expert]

I don’t know whether the effect is significant, but adding something like vinegar will increase heterotrophic bacteria (those that live by eating organics) and those increased numbers may drive a lowering of slower to be consumed organics in the water.

So it seems plausible to me.

 

[JonasRoman]

I think that's true because I believe this happens:
Organic carbon dosing will be consumed (oxidized) by heterotrofic bacteria, so at least theoretically so far its no change in DOC as added organics is consumed.
But now, when this added organics is consumed it has increased bacterial population with same extent as the added carbon. As long as we now do not increase the addition but keep it at same dose, the increased number of bacteria will need more than just the addition, so a total decrease of DOC will occur. Maybe though to a new equilibrium as now bacterial growth will decline, so we reach a new steady state. As long as,we do not increase the added carbon further no further nettovonsumption of DOC will occur.

I do not know for sure if this is what happens but just try to find a hypothesis that could explain what Sprung says occur.

Any other thoughts from you?

 

[jeremie]

This process is known as the "priming effect" and is quite well studied in soil research.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JG006201⁠
The outcome in aquatic environments does appear to be a bit more complicated, and the results may depend on factors such as the type of organic compounds involved or the availability of other nutrients.

 

[Dan_P]

This process is known as the "priming effect" and is quite well studied in soil research.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JG006201⁠
The outcome in aquatic environments does appear to be a bit more complicated, and the results may depend on factors such as the type of organic compounds involved or the availability of other nutrients.

Thanks for the reference. Complicated is right.

 

[Dan_P]

Hello reefers!

Julian Sprung was recently in Brazil and did a nice speech about DOC.

In one of his slides, he suggest means to reduce it. One is dosing organic carbon.

It seems contraditory but so does algae refugium/ reactor as algae also release DOC.

What do you think?

Did he suggest any organic carbon or type of chemical in particular? Did he provide data to demonstrate its effectiveness? Or did you feel he was conjecturing? If I recall correctly, @Lasse thinks it can happen.

 

[Dan Reef]

Did he suggest any organic carbon or type of chemical in particular? Did he provide data to demonstrate its effectiveness? Or did you feel he was conjecturing? If I recall correctly, @Lasse thinks it can happen.

No, but it is in his presentation named Husbandry Techniques that control DOC and may influence these states

The carbon dosing was one of the techniques among others such as: algae filtration, skimmer, bio pellets, etc

 

[Dan Reef]

Did he suggest any organic carbon or type of chemical in particular? Did he provide data to demonstrate its effectiveness? Or did you feel he was conjecturing? If I recall correctly, @Lasse thinks it can happen.

No, but it is in his presentation named Husbandry Techniques that control DOC and may influence these states

The carbon dosing was one of the techniques among others such as: algae filtration, skimmer, bio pellets, etc

 

[Subsea]

Exudates from photosynthesis are DOC. The DOC from coral are mostly proteins & amino acids. The DOC from algae are mostly carbohydrates.

Sounds like DOC are necessary building blocks for coral.

https://pmc.ncbi.nlm.nih.gov/articles/PMC3635233/

“Dissolved organic carbon (DOC) released by corals and algae shapes very different bacterioplankton communities in reef ecosystems. Coral exudates support stable, diverse, and beneficial bacteria, while labile macroalgal DOC triggers fast growth of opportunistic, potentially harmful microbes linked to the DDAM (DOC, Disease, Algae, Microorganisms) feedback loop. [1, 2]”


Overview

“Corals and algae release dissolved organic carbon (DOC) with distinctly different chemical compositions and quantities, which uniquely shape surrounding reef microbial communities. Corals tend to exude complex, proteinaceous molecules and aromatic amino acid-like compounds, whereas algae release large amounts of labile simple sugars and humic-like substances. [1, 2, 3, 4, 5]”

 

[Dan_P]

No, but it is in his presentation named Husbandry Techniques that control DOC and may influence these states

The carbon dosing was one of the techniques among others such as: algae filtration, skimmer, bio pellets, etc

Thank you for the information. DOC was recently a hot topic for coral enthusiasts. Sounds like it is still being discussed.