Can Coral take up CACO3 directly

[steven4200]

The title says it all, but here is my question in more detail as well as my own grasp of the concept. I understand that coral take up carbonate or bicarbonate along with calcium (CA++ in seawater), if they take up bicarbonate, they convert it into carbonate along with calcium to create a calcium carbonate skeleton. I also understand that the PH determines what form carbonate or bicarbonate will take along with its effect on the solubility of calcium carbonate in the water. So, my question is this. Can coral take calcium carbonate directly from the water column and incorporate it into their skeleton? If so, does calcium carbonate undergo any changes in this process or is it directly assimilated into the skeleton? Please do not be shy with complex answers here. A detailed explanation would be appreciated. I don't hold any formal degrees in Biology or Chemistry so please keep that in mind, but I love this aspect of the hobby! I would appreciate a detailed answer or any input if my understanding is incorrect from someone who really knows what they are talking about.

 

[Phildago]

I'm not an expert either on this, but from my understanding calcium carbonate is relatively insoluble in water. So, even if the could potentially, it would be difficult.

Are you asking it they can eat it and incorporate it that way?

 

[FranklinDattein]

No, they can't.
Their skeleton building process consists of combining Calcium ions (Ca2) with Carbonate ions(Co3), to form CaCo3. Providing CaCo3 directly won't make into any part of the biological process responsible for building skeleton.

A simple way to think about it, is that if they could, they would be able to incorporate their own skeleton, in an infinite loop.

 

[Randy Holmes-Farley Verified Community Expert]

Calcium carbonate is not something present in the water except perhaps as particulates, what are not usable.

 

[Randy Holmes-Farley Verified Community Expert]

This article of mine is getting old now, but I think it is still essentially correct in its summary of calcification mechanisms by corals:

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification - Reefs.com

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification - All reef aquarists are versed in the fact that such organisms remove calcium and carbonate from the water column in order to provide materials for calcification. Exactly how calcification takes place, however, is...

www.advancedaquarist.com

 

[Cory]

Amorphous calcium carbonate particles form coral skeletons

Whether coral skeleton crystals grow by attachment of ions from solution or particles from tissue determines ( i ) corals’ growth rate, ( ii ) how they survive acidifying oceans, and ( iii ) the isotopes in the crystals used for reconstructing ancient temperatures. Our data show that two...

www.pnas.org

What are they saying here? Something about 400nm particles of calcium carbonate.

 

[steven4200]

This article of mine is getting old now, but I think it is still essentially correct in its summary of calcification mechanisms by corals:

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification - Reefs.com

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification - All reef aquarists are versed in the fact that such organisms remove calcium and carbonate from the water column in order to provide materials for calcification. Exactly how calcification takes place, however, is...

www.advancedaquarist.com

Thank you I will be sure to give it a read. I have read most of your articles they are the primary reason I know as much as I do. Thanks for taking the time to write them! Do you know of any good articles that explain PH in depth. I feel that I have a good understanding of it and how it effects solubility and ions in general, but I would like to know more.

 

[Randy Holmes-Farley Verified Community Expert]

Amorphous calcium carbonate particles form coral skeletons

Whether coral skeleton crystals grow by attachment of ions from solution or particles from tissue determines ( i ) corals’ growth rate, ( ii ) how they survive acidifying oceans, and ( iii ) the isotopes in the crystals used for reconstructing ancient temperatures. Our data show that two...

www.pnas.org

What are they saying here? Something about 400nm particles of calcium carbonate.

the article is talking about a detail in the mechanism of skeleton formation within the coral, not how the coral gets the calcium and carbonate to begin with.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you I will be sure to give it a read. I have read most of your articles they are the primary reason I know as much as I do. Thanks for taking the time to write them! Do you know of any good articles that explain PH in depth. I feel that I have a good understanding of it and how it effects solubility and ions in general, but I would like to know more.

Sure: http://www.reefedition.com/ph-and-the-reef-aquarium/