The monograph generalizes multi-year investigations on the energy metabolism and motility of marine planktonic organisms, from flagellated algae to salps, from different regions of the World Ocean. The effect of various factors changing activity and metabolism during experiments has been considered. Common features and differences in the character and speed of movement of organisms with different ecology have been demonstrated. Data on basal, standard, and total metabolism have been compared; current approaches have been taken into account, and new approaches and methods for the estimation of metabolism when approaching ecological problems are suggested.