Photosynthesis or planktonic respiration?

Scientists Paul A. del Giorgio et al believe that planktonic bacteria living in the euphotic zone of the oligotrophic sea undergo respiration more than photosynthesis. They calculate the level of bacterial respiration using a respiratory quotient of 1.0 carbon dioxide per oxygen consumed. However, scientist Richard J. Geider believes that a net heterotrophic environment does not exist in the ocean although it may very well exist in lakes.