So where did all the Strontium go?

[dnjan]

I found it interesting that though the IO mix and natural seawater have similar levels of strontium, the tested tank waters generally had 1/3 to 1/2 that amount. Where is it going? I understand that in some cases strontium can substitute for calcium in the calcium carbonate matrix, but was a bit surprised by the "consistant" consumption of strontium in the majority of the samples.

 

[Randy Holmes-Farley]

dnjan:

You're right that it is incorporated in CaCO3 skeletons.

Remember that you are constantly replacing calcium as it is used up, but not strontium. Consequently, even a tiny incorporation over time can lead to a substantial depletion. This is especially noticeable since strontium has a far lower concentration than calcium to start with.