CaCo3 + chitin help make up the horseshoe crab’s shell.
(See earlier post for information on chitin.)
People complain that it is tough and hard if they step on one. These two elements are the reason why.
One question I always ask the students who come is: what are your bones made out of? The sad fact is that the majority do not know. They know about the TV commercials telling them to drink milk for strong bones but they don’t know WHAT makes their bones strong.
Calcium is the link between all living creatures that have bones and shells. Calcium is the fifth most abundant element on earth and has many variations (I’m not getting into more than basic chemistry here). One of the variations that link us to the horseshoe crabs and all of the other shelled animals like oysters and lobsters is CaCO3, or calcium carbonate.
Calcium carbonate is a calcium compound. We use it all the time and use products that contain it all the time like toothpaste, vitamins, almond milk, as a calcium supplement, and when we eat dark green vegetables like kale.
Calcium carbonate may have the ability to neutralize acid rain in river water and river ecosystems even though it is not soluble, or dissolves, in water.
CaCO3 is the reason we have fossils of horseshoe crabs going back 450 million years. It is also the reason their shells are so strong and tough. It is their home, their refuge, their protection. CaCO3 is the reason they can travel hundreds of miles through the water and then make it to the shores to lay their eggs.
Calcium carbonate is the reason we get to see them now.