A couple questions

[Kungpaoshizi]

I'm following a tangent of thought, but am by no means an expert. Randy if you can answer it or anyone else has a thought, please share.

1. Has there ever been a coral analysis, that contained strontium-free aragonite?
2. Has there ever been a coral analysis, that did not contain Magnesium?

I guess I'll start there before I get too ahead of myself.. Tyvm!

 

[Randy Holmes-Farley Verified Community Expert]

I've not seen coral skeleton analysis in great numbers, but I would expect there would not be any calcium carbonate formed in the ocean that did not contain strontium, whether by a coral or simple precipitation. Strontium looks chemically like calcium and mangesium, and naturally gets into calcium carbonate in place of calcium to a degree which depends on the relative amounts of calcium and strontium in the water. The same is true to a greater degree for magnesium since there is so much more of it.

Consequently, to make a calcium carbonate skeleton without any strontium would imply the the organism went to efforts to exclude it from the area where formation was taking place. That seems to not be the case for many corals, and it gets in.

The same discussion relates to magnesium, except magnesium is present at far higher concentrations so gets in to a greater extent.

Finally, strontium and magnesium will get into the near surface regions of pure calcium carbonate that is put into seawater. It simply swaps out calcium for strontium or magnesium. So no matter what was originally synthesized, there will be strontium and magnesium in it if it is exposed to seawater.

 

[Kungpaoshizi]

The other part of that is I've been looking for even fossilized analysis, or more recent time periods after organism death.
Perhaps they're dumb questions since it's established? (or has there been exceptions maybe?)(https://en.wikipedia.org/wiki/Paleothermometer)

 

[Randy Holmes-Farley Verified Community Expert]

It is well studied, yes.

 

[Kungpaoshizi]

Any studies that you know of that found Mag being elevated increased growth/etc of a coral? Or other elements than calcium either? (I assume increasing carbonates are common studies)

 

[Randy Holmes-Farley Verified Community Expert]

I've not seen any studies of what happens to coral growth with elevated magnesium, but magnesium reduces abiotic preciditation by getting onto the crystal surfaces and poisoning it for further calcium carbonate precipitation. That is one of the main ways the ocean stays supersaturated with respect to calcium carbonate despite seed crystals of calcium carbonate all over the place.

 

[Kungpaoshizi]

You mentioned in another post that aragonite can form, strontium-free? Can the same be said about calcite and magnesium?
Is this referring to a natural source or man-made?