Dissolved organic carbon seasonality in the Northern Adriatic and its possible involvement in the aggregate formation

Dissolved organic carbon (DOC) concentrations in northern Adriatic coastal waters show seasonal variations with increasing values from winter (75-95 ?M in February) to spring-summer periods (120-190 in June 1996 and 85-123 ?M in June 1997). Riverine inputs of refractory organic matter and abiotic transformations of in situ produced biogenic matter contribute to the accumulation of DOC. Phosphorus limitation of bacteria, whose productivity varied widely with time and space (0.01 to 7 ?g Cl-1 h-1), probably concurs to this seasonal DOC behaviour making microbial community unable to contrast the enrichment in DOC concentrations. Possible involvement of DOC accumulation in the gel production in the Adriatic sea are discussed.