That part struck me the most. Thinking of consciousness from another perspective is an entirely new/interesting concept for me. Considering the length of time bacteria has been around, bacteria might interpret humans as we interpret other Earth cycles, like the Ice Age.How easy would it be for an intelligent bacteria to notice people as integral entities? We might appear more as slow storms moving into the bacterial environment. If we are relying solely on the human perspective to validate machine consciousness, we're really only putting human-ness on an even higher pedestal than it might have been at the start of our thought experiment.
This book is for you:
And, now that I think about it, also check out Solaris (the Stanislaw Lem book), the short story "Mimsy were the Borogoves" (not the horrible movie THE LAST MIMSY which pretends to be based on it but isn't) and the Silverberg Sophocles adaptation "The Man in the Maze":