Residence Times in a Hypersaline Creek: Using Salinity as a Tracer

Spatial measurements of conductivity, temperature and depth were used to study salinity variations along the principal channels of the tidal hypersaline creek network in the vicinity of Bushehr Port, Persian Gulf during three 25- tidal cycles in both warm and cold months. Salinity variations and tidal fluctuations were out of phase throughout the short inverse estuary. The salinity values inside the creek were higher during the warm month (August 2014) than the corresponding values during the cold month (December 2014) due to the change in evaporation rates. The salinity values, also, were linearly increased longitudinally from the inlet to the head especially during warm season. Observed evaporation rates in August and December periods and the corresponding salinity differences between hypersaline water of the creek and the incoming seawater were used to determine the Residence Time (RT). The longitudinal variation of RT showed almost linear increase from the inlet to the head. The maximum temporal distribution of RT represented an increase from ~10 days in winter to ~30 days in summer due to the change in the longitudinal salinity gradient.