I'll add to David spot on statements.
Coral head islands have large outcroppings of coral and the beach sand is coral. Parrot fish with beaks like parrots Chomp down on a living coral, crush it and have lunch. Then flakes of coral flow out the gills. They create massive coral 'sand' flows. I suppose this is a way to make the coral grow to reclaim area. I used to skin dive and drive down to 10 or more meters to collect shells in coral sand. I saw this on Kwajalein Atoll in the Marshall Islands in the 60's.
This is a massive CO2 bank stored in thousands of feet of coral
walls making the atoll.
Martin Eastburn
[log in to unmask]">Shallow water also tends to be more saturated with carbonate ions, which makes it easy for both biological and abiological processes to produce carbonate minerals. Many parts of the very deep ocean are undersaturated in carbonate to the point of making carbonates dissolve if they sit around long enough.
The carbonate saturation level relates to pH, so increasing CO2 makes it harder to make shells.
I was going to say the exact same thing.---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------
Susan Hewitt
On Nov 16, 2023, at 7:20 PM, Allen Aigen <[log in to unmask]> wrote:
---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------Probably the encrustations are from calcareous algae which grows best with lots of light, like in shallow water.Allen AigenStaten Island NY
On Thursday, November 16, 2023 at 05:02:16 PM EST, John Varner <[log in to unmask]> wrote:
---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------Is it my imagination, or are shells found in shallow water more likely to be encrusted with calcium deposits? And why is that?
--
---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------Dr. David CampbellAssociate Professor, GeologyDepartment of Natural Sciences110 S Main St, #7270Gardner-Webb UniversityBoiling Springs NC 28017