Nicki Minaj -- AQUA-TWERK ... In a Bikini

She's twerked on land ... and now Nicki Minaj is twerking at sea -- and fortunately for the human race, she captured the entire aquatic adventure on tape.

A bikini-clad Minaj twerked off inside of a swimming pool -- wearing a skimpy little bikini that accentuated her legendary badonk.