What makes Aqualung special is not their unusual instrumentation—which includes saxophones, marimba, congas, and vocals. Neither is it the group's eclectic diversity of compositions, which span Latin, bop, and free jazz styles. Nor is it the obscure origin of these accomplished musicians, who all hail from a tiny island called Congee in the South China Sea. It's the mere fact that Tsunami was exclusively recorded underwater.

Such a feat requires incredible resources at all levels. The engineering, according to conga player Simon Yedun, was actually the hardest part. Yedun has a doctorate in fluid dynamics, and he puts that advanced knowledge to great practical use here. It turns out that sound waves travel very differently in an aqueous environment, so extreme close-miking is required to capture submarine timbres. Yedun records his congas using several small units arrayed around the body of the drum. He mikes the marimba with one unit per tone, using computer-enhanced processing to synthesize a complete range over the instrument's entire spectrum.

The instrumentalists here have spent many long hours perfecting their skills, practicing near the coral reefs off the North shore of Congee. Yedun has quick hands on the conga, riding Afro-Cuban styles like a fresh ocean breeze. Marimba player Alison Beate seems equally comfortable with the music of the islands as she is with more challenging material—such as the free jazz tone poem "100-yard freestyle," a turbulent one-minute exercise in spontaneous invention. (That's mere seconds off the record.)

Perhaps the most amazing performer on this record is saxophonist Tim Dongee. Dongee has developed a method for combining the usual sounds of his instrument with strategically placed bubbles, in much the same way that modern saxophonists employ overtones. Water and air. It's hard to be subtle with such powerful tools at his disposal, but Dongee gets it right. Amazingly, he has also developed a method for underwater circular breathing on his instrument. He won't give up his secret other than to say that he employs a specialized scuba apparatus, but Dongee can play continuous solos for up to five minutes long, as on the swinging hard bop tune "Lone Shark."

Having already released three records on their private Congee label, Aqualung hopes to finally reach an international audience with Tsunami. Based on these tunes, it seems likely the quartet will draw attention. Their sound is completely unique. Who knows, they might even inspire a whole new school of jazz!