Learn Turkish: Penguenlerin ve fokların buzun üstünde uyuyor olması harika. - It is wonderful that the penguins and the seals are sleeping on the ice.

The form uyuması is a standard verbal noun meaning "their sleeping" in a general sense. By combining the continuous suffix -Iyor with the verbal noun olması (from olmak), you emphasize the ongoing aspect of the action. It translates specifically to the fact that they are currently sleeping right now.

The subjects are plural (penguenlerin ve fokların), so why does the verbal noun use the singular possessive olması instead of olmaları?

In Turkish, when a plural subject is non-human (such as animals, plants, or objects), the verb or verbal noun generally remains singular. Since penguins and seals are animals, olması is grammatically correct and sounds much more natural than olmaları.

Why do penguenler and foklar take the genitive endings (-in and -ın)?

They are the subjects of the nominal clause "that the penguins and seals are sleeping". In Turkish factive clauses like this one, the subject takes the genitive case, essentially acting like "the penguins' and seals' being sleeping". This links directly to the 3rd person possessive suffix -sı on olması.

Could we just say buzda instead of buzun üstünde?