Such strong water movements greatly af-fect the pattern of salinity in an estuary. Another factor that affects circulationin estuaries is the
Coriolis effect.
Northof the Equator, the fresh water that flowsfrom rivers toward the sea is deflected to- ward the right. South of the Equator, theflow is to the left. This means that in es-tuaries located in the Northern Hemi-sphere marine organisms can penetratefarther upstream on the left side when onefaces seaward. In the Southern Hemi-sphere they extend up the right side.In regions of little freshwater runoff and high evaporation, the salinity of the water increases. An example is LagunaMadre, a shallow bar-built estuary withlimited access to the open ocean that par-allels the Texas coast for 185 km (115 mi).