sample  cruise_id  season  mon_year  date        time  water_mass                     depth  technology  
841     AE1203     winter  Feb_2012  2012-02-23  1730  mixed_layer                    30     454         
842     AE1203     winter  Feb_2012  2012-02-24  0600  mesopelagic                    1000   454         
843     AE1203     winter  Feb_2012  2012-02-24  1400  mixed_layer                    80     454         
844     AE1203     winter  Feb_2012  2012-02-25  0800  mixed_layer;upper_mesopelagic  180    454         
883     AE1220     summer  Aug_2012  2012-08-08  1530  deep_chlorophyll_max           130    454         
884     AE1220     summer  Aug_2012  2013-08-09  0825  mixed_layer                    60     454         
885     AE1220     summer  Aug_2012  2013-08-09  1745  mixed_layer                    30     454         
886     AE1220     summer  Aug_2012  2013-08-10  0815  mesopelagic                    1000   454