I... I think you found the end of the Internet.
Isn't that the seawater pumping room?
Yes, and that's where they dump heat from the closed internal fresh-water loop into the bay-water loop. That's what the titanium hex grid is.
The Academy of Sciences has an equally, if not more, epic series of tubes supporting their various aquariums and atriums. I highly recommend that tour.
I can second this. They have tubes that go out to the ocean, despite being the most landlocked spot in the city.