RÉSUMÉ
Bioavailable dissolved organic carbon (BDOC), nitrogen (BDON) and their degradation rate constants were measured for the Chilika Lagoon, India. Long-term laboratory incubation experiments (90â¯days) were conducted at a constant temperature (25⯰C) to quantify the bioavailable dissolved organic matter (DOM) and the possible degradation rate coefficients. The results showed that 41⯱â¯12% of dissolved organic carbon (DOC) and 47⯱â¯17% of dissolved organic nitrogen (DON) were BDOC and BDON respectively, with their stoichiometry found to be higher than the Redfield ratio. A first order exponential non-linear fitting routine was used to estimate pool sizes. The degradation rate constant (k) for the BDOC varied from 0.127-0.329â¯d-1 and BDON from 0.043-0.306â¯d-1 during the study period. Half-lives of the BDOC and BDON ranged from 2.1-5.4 and 2.2-15.9â¯days, respectively. Overall, the results showed that a fraction of the labile DON was transported from the lagoon to the adjacent coastal sea.