Acoustic attenuation in Lake Tanganyika

THE Lake Tanganyika acoustic attenuation experiment of April 1970 (ref. 1) was the second of two lake experiments designed to help identify the cause of the low-frequency attenuation anomaly in seawater by providing comparative freshwater data. Although the Lake Tanganyika results showed no evidence of the anomaly, the attenuation was unaccountably large. Recent laboratory experiments have shown that the anomaly arises mainly from a chemical relaxation involving boric acid 2 . We have been investigating pertinent chemical equilibria using the acoustic resonator technique 3 and we have encountered another chemical relaxation–absorption in seawater 4 that is evidently also responsible for the Lake Tanganyika results.