The low oxygenation of the harbour has been a characteristic
feature for a long time (Dorgham et al., 2004; Farag,
1982), but the present study showed that water was welloxygenated
all the year round and no anoxic phenomenon
was observed. Oxygen concentrations generally ranged
between 5.34 and 22.08 mg l
1
, corresponding to 71%
and 266% O2 saturation, respectively. Peak O2 saturation observed during spring (average: 205%) could be a direct
indication of high phytoplankton density. This is well known
from the strong positive correlation with phytoplankton
counts (r = 0.703, p < 0.001). Oxygen solubility
was strongly negatively influenced by water salinity and all
nutrient salt concentrations.