Why do aquatic animals typically have a faster rate of breathing compared to terrestrial animals?

Aquatic animals generally exhibit a faster breathing rate than terrestrial animals due to the lower oxygen concentration in water and slower diffusion of gases. Dissolved oxygen in water is less abundant than in air, necessitating aquatic animals to ventilate their respiratory organs at a higher rate. To compensate for the lower diffusion coefficient of gases in water, these animals actively move water over their respiratory surfaces, such as gills, requiring a faster breathing pace. Additionally, the energetic cost of buoyancy in water may contribute to increased oxygen demands. Physiological adaptations, like specialized respiratory structures, further emphasize the need for a rapid exchange of gases. While variations exist among aquatic species based on environmental conditions, these factors collectively underline the trend of faster breathing rates in aquatic animals compared to their terrestrial counterparts.