This is a limacina or a sea butterfly. Its shell was exposed to CO2 and dissolved in water over 45 days.
The level of CO2 was increased to show the effect of climate changes on Earth: emissions of carbon dioxide into the atmosphere increase its concentration in water and lead to ocean acidification forcing some marine species into extinction.
A mysterious pond with blue water
This pond is surrounded by legends. It’s said that people who swim in it, die soon afterward. If you pour this water in a glass, it loses its unusual color. According to one of the theories, it’s all about the minerals at the bottom of the pond.