This is a broad-snouted caiman underwater video.
They are eggs of the broad-snouted caiman. This species has never before laid any eggs in a Dutch zoo. At the moment, the only other Dutch zoo with these caimans is Burgers’ in Arnhem; but there, they are still too young to reproduce. Only five European zoos have broad-snouted caimans.
Effects of climatic conditions on sex ratios in nests of broad-snouted caiman: here.