Pistol shrimp make "cement"?

[TinCanHero]

Hey guys!

Just a little observation I made the other day while breaking down my tank to move house.
I have a pistol shrimp called clappy claws, I love the little guy. He has been in that tank for around 2-2.5 years. in that time he had obviously made a bunch of tunnels around the tank (RSR 200xl).

My sand is TMC eco sand, its a crushed shell rather than real sand with a medium particle size. I started to tare down the tank and my first thing was to remove the main rock. under that i found a ton of frags (little **** that he is), nothing out of the ordinary.

However where it gets interesting is some side tunnels i didn't know about, they branched off into bare sand. these tunnels where capped with what i could only describe as cement around 2-3mm thick totally solid and fused together. i could break it in half and it breaks in a clean way and the sand will not break apart nor "rub off", its a fused structure.
the largest of these was around 5-6" long and 4-5 wide. with all the sand missing below it, a true tunnel / cave celling.

There was 3? i think in total in the tank, two small ones and this large one along with a big cave under the main rock and another large one under a side rock.

So yeah, just a interesting thing i observed! i cannot find anything documented about this online? anyone have any information? id love to learn more about this!

And here i was all this time worrying that he didn't have the best substrate to tunnel in.. LOL!

-These are the only pics i took, i was a stressful day to say the least!

 

[shakacuz]

weirdly enough, this did not happen to me when i had to tear down my tank earlier this year(40B with a very happy pistol shrimp). could be another reaction that occurred. i vaguely remember it possibly being calcium. perhaps @Randy Holmes-Farley can provide some insight.

 

[TinCanHero]

weirdly enough, this did not happen to me when i had to tear down my tank earlier this year(40B with a very happy pistol shrimp). could be another reaction that occurred. i vaguely remember it possibly being calcium. perhaps @Randy Holmes-Farley can provide some insight.

Could be, it is however just local to where the shrimps tunnels / caves where so I just assumed it had something to do with the shrimp, maybe they produce some binding agent but i couldn't find any reference to it.

but thinking about it, it could also be some other reaction that's happening because of the tunnels allowing water more freely at that point, no idea..!

 

[twentyleagues]

I have heard of localized calcification not sure what exactly causes it I think heat can be one source. It is possible that the tunneling caused some kind of water flow something or other (not a scientist lol).