Curious about cobalt

[Righteous]

I’m curious if anyone can report on experience with dosing cobalt or it’s levels within their tank, or perhaps any association with vitamin B12 (cobalamin, which contains cobalt)

I haven’t seen much in the way of cobalt showing up in peoples ICP tests, and based on an older article of Randy’s, my understanding is that the ICP LOD for cobalt is 0.4 µg/L which also happens to be about the upper limit of concentrations found in the ocean.

My curiosity stems from reading about cobalt as a limiting nutrient for phytoplankton, cyanobacteria and diatoms. Bacteria specifically require cobalt in order to produce B12 which is the source for B12 for the entire food chain. As an example of its importance, cattle and sheep’s only source of B12 is synthesized via bacteria in their gut, and it was found soil lacking cobalt resulted in “bush sickness” of the cattle as their B12 producing bacteria became deficient.

Given that we’ve found bacteria seem to play a profound role as a food source (and occasional pathogen) for coral, is there any evidence that cobalt might be lacking? Does anyone know if cobalt from B12 added with food can be scavenged and utilized by bacteria for their own B12 needs?

I’ve recently begun increasing my molybdenum dosing, which has always been very low on all my Triton tests. I’ve started dosing it daily, and my very anecdotal evidence is that cyanobacteria matting seems somewhat reduced and coral growth has improved. Molybdenum is used in numerous enzymes in bacteria, and clearly is used up at a considerable rate in my aquarium. (On another very interesting tangent is the theory that the limiting factor of molybdenum in earths early oceans may have played a role in eukaryotic evolution)

With that experience in mind, cobalt seems like a possible important element at the bottom of the food chain, but given it’s low concentrations and difficulty measuring it, clearly it’s not an easy thing to experiment with.

Please also note, I’m running a Triton method tank, meaning no water changes and maintaining natural sea water levels of elements via Triton element dosing. It’s certainly a healthy tank and doing well as is, so I consider this an advanced experimental topic.

 

[Anthony Scholfield]

This seems very interesting. This probably isnt the exact experience your looking for but i use a product called Aquavitro Fuel. This product contains cobalt and molybdenum, amongst other things. Their webpage gives a break down of it all.

So this is very ancedotel but i used this product for a period of time (approx. 6 months) and felt the results were good. It seemed the tank responded well. Like most of these liquid products, i often question their value. So i stopped using it for a time (approx. 6 months). During the non use i cant say the tank suffered but i often felt like it was missing some pop it had before. Coiuldnt put my finger on it.

So recently, approx. last 3 months, ive been using it again. I wont report at this time that my tanks magically have some wild pop but i will say i see interesting changes for the good. Such as color improvement and less dusty algae on the sand bed. Also, i have seen cyano disappear in one of the systems. There are likely some other factors in play but im believing its contents are beneficial to my reefs.

I dose it daily. 2ml on each system of approx. 50g, 40g, and 30g water volumes.

 

[taricha]

Given that we’ve found bacteria seem to play a profound role as a food source (and occasional pathogen) for coral, is there any evidence that cobalt might be lacking? Does anyone know if cobalt from B12 added with food can be scavenged and utilized by bacteria for their own B12 needs?

B12 is an essential nutrient for growth of algae which can't make their own and they don't eat foods containing it, so they must acquire it somehow. Most aquarium foods contain B12, so I'd guess it's difficult to run into a hard limitation of it.
B12 is synthesized by cyanobacteria (called "cyanocobalamin"). Is it possible that an absolute depletion of cobalt can halt the in-system synthesis of B12 by cyano? maybe? but as you mentioned, the amounts of cobalt are never going to be easily measurable.
Is stopping or encouraging synthesis of B12 desirable or undesirable? no idea.

 

[Righteous]

Is it possible that an absolute depletion of cobalt can halt the in-system synthesis of B12 by cyano? maybe? but as you mentioned, the amounts of cobalt are never going to be easily measurable.
Is stopping or encouraging synthesis of B12 desirable or undesirable? no idea.

Cobalt is definitely required for B12 production, as it forms the center of the molecule. So absolute depletion of cobalt would halt B12 production. We know that deficiency in cobalt does just that in ruminants. I think part of the issue would be, is a complete depletion even possible. I would assume in a tank like mine with no water changes it’d be more likely, but even with water changes it’s clear some micronutrients get taken up very rapidly. It’s also possible B12 might be scavenged by other organisms, releasing the cobalt for it to be taken back up. I don’t have any data on that though.

B12 is extremely important for all organisms as it plays a role in DNA synthesis. Also given that it is only created by bacteria and archaea most animals and plants have very specialized methods of obtaining it (humans require intrinsic factor in the gut to extract it). So it’s also not clear that direct B12 supplement can be utilized.

I managed to find this paper that seems to find that zooxanthellae won’t generate their own B12 and instead rely on bacteria to acquire it, and generally the importance of bacteria in coral

the coelenteric bacteria may play one of the main roles in the maintenance of the coral symbiotic complex as producers of vitamin B12, which is then used by the coral host and the zooxanthellae

and:

corals were thought to form an open system having a robust water exchange with the surrounding water. Our results lead to a fundamental reevaluation of the principles of the coral symbiotic complex which consists of (1) essential compounds such as vitamin B12 and nutrients for the symbiotic complex being produced through internal processes driven by bacteria,

https://www.jstage.jst.go.jp/article/galaxea/11/1/11_1_1/_pdf

I believe toxic levels of cobalt are much higher than the LOD of ICP-OES, so perhaps I might aim for 0.4 µg/L and just see what happens. I’m assuming toxic levels are more in the 10+ µg/L range, but if anyone has any more info on that I’d like to know.

 

[Righteous]

This seems very interesting. This probably isnt the exact experience your looking for but i use a product called Aquavitro Fuel. This product contains cobalt and molybdenum, amongst other things. Their webpage gives a break down of it all.

So this is very ancedotel but i used this product for a period of time (approx. 6 months) and felt the results were good. It seemed the tank responded well. Like most of these liquid products, i often question their value. So i stopped using it for a time (approx. 6 months). During the non use i cant say the tank suffered but i often felt like it was missing some pop it had before. Coiuldnt put my finger on it.

So recently, approx. last 3 months, ive been using it again. I wont report at this time that my tanks magically have some wild pop but i will say i see interesting changes for the good. Such as color improvement and less dusty algae on the sand bed. Also, i have seen cyano disappear in one of the systems. There are likely some other factors in play but im believing its contents are beneficial to my reefs.

I dose it daily. 2ml on each system of approx. 50g, 40g, and 30g water volumes.

Thanks for sharing. I’ve often wondered if some peoples success with supplements like these, and other people seeing no effect, comes down to whether it’s solving a deficiency or not. I’d also guess that many tanks have very different bacterial ecosystems which could change the balance in various directions for different tanks.