ABSTRACT
Freshwater and dissolved nutrient inputs that entered the lower Seybouse River estuary were assessed in 2012 through a fortnightly surface water sampling both at a lower river station and at the estuary outlet. The Seybouse estuary delivered annually 950 × 106 m3 of freshwater yielding 83 kg N km-2 yr-1 of N-NH4 and 12 kg P km-2 yr-1 of P-PO4. More than 2/3 of the annual inputs of freshwater, Si(OH)4 and NO3 entered the sea during the flooding event of late February 2012. Si-Si(OH)4 and N-NO3 yields in the Seybouse estuary represented <1/3 those of the Mediterranean rivers. Annaba Bay is subjected to highly polluted waters from the Seybouse estuary, with significant NH4 (72 ± 37 µmol L-1) and PO4 (7 ± 4 µmol L-1) amounts. However it is characterized by low Si(OH)4 (104 ± 43 µmol L-1) amounts. Alteration of Si:N:P ratios at this bay suggest potential risk of eutrophication, except during and weeks after flood episodes.