Very interesting, I had thought they were sustainable for much longer than that. I suppose even the most tightly controlled starting conditions will lead to unpredictable results when you have organisms reproducing.
I think these are more about the incredible toughness of the shrimp involved. Their native habitat consists of rainwater puddles held in volcanic rock, so the shrimposphere is probably fairly luxurious.
Pretty much; this guy[1] claims that basically, the shrimp slowly starve over the course of a couple years, shrinking after each molt.
Your shrimp are new shrimp made out of the same molecules as their ancestor shrimp.