DOC varied from 53 μmol C l - 1 to 149 μmol C l - 1 among all the samples collected. In the 0-50 m layer DOC concentration was on average 1.2 times greater than in deep water. In the upper 50 m, annual variation was pronounced, with an increase in DOC concentration in spring and summer of variable timing and magnitude, and a less variable decrease in DOC concentration starting in August-September. During 1992 a pulse of DOC at depths between 400 and 800 m was measured; this change presumably was caused by advection. Within the resolution limit, changes in the deep water from 1000 to 2000 m were hardly detectable and not related to annual cycles.