The musical Sea Organ (2005), by Nikola Bašić, is located on the shores of Zadar, Croatia, and is the world’s first second musical pipe organ played by the sea. Simple and elegant steps, carved in white stone, were built on the quayside. Underneath, there are 35 musically tuned tubes with whistle openings on the sidewalk. The movement of the sea pushes air through, and – depending on the size and velocity of the wave – musical chords are played. The waves create random harmonic sounds.

Each musical organ pipe is blown by a column of air, pushed in turn by a column of wave-moved water, through a plastic tube immersed into the water. The pipes’ musically tuned sounds emanate to the surroundings through apertures in the vertical planes of the uppermost stairs. The 7 successive groups of musical tubes are alternately tuned to two musically cognate chords of the diatonic major scale. The outcome of played tones and/or chords is a function of random time and space distribution of the wave energy to particular organ pipes. [via]

Read Acoustical and Musical Solution to Wave-Driven Sea Organ in Zadar [PDF] by Ivan Stamać.

The Wave Organ (1986) is a wave-activated acoustic sculpture located on a jetty in the San Francisco Bay. The concept was developed by Peter Richards and was installed in collaboration with sculptor and master stone mason George Gonzales. Inspiration for the piece came from artist Bill Fontana’s recordings made of sounds emanating from a vent pipe of a floating concrete dock in Sydney, Australia.

The installation includes 25 organ pipes made of PVC and concrete located at various elevations within the site, allowing for the rise and fall of the tides. Sound is created by the impact of waves against the pipe ends and the subsequent movement of the water in and out of the pipes. The sound heard at the site is subtle, requiring visitors to become sensitized to its music, and at the same time to the music of the environment. [via]

Richards believes the true beauty of the Wave Organ is the way nature’s many sounds mix together. “If I just sit here and listen, I will hear the sounds of the wave organs but hear other sounds as well. Blended together, it becomes [an] environmental symphony…” [via]