This activity shows you how seasonal differences bring about changes in stratification of water bodies. In each pane you will find a description of typical water conditions that occur during spring, summer, and fall.  Choose the conditions you think best describe the temperature and the salinity at the surface and at the bottom. Remember that river water has very low salinity (0-5), while marine water has a high salinity as it is entering the bay (32-35), and that the two water masses will mix to some degree. After you have filled in all the boxes, click the “Check It!” button to discover how close you were!