before_sent:  The origin of currents is owed to physical differences between various water masses, the main parameter being the difference of density that varies in function of the temperature and the concentration of salt .
before_sent_with_intent: <clarity>  The origin of currents is owed to physical differences between various water masses, the main parameter being the difference of density that varies in function of the temperature and the concentration of salt .
after_sent:  The origin of currents is owed to physical differences between various water masses, the main parameter being the difference of density that varies in function of the temperature and salinity .