Starvation's role in plankton metabolism

Abstract

Starvation at all scales of plankton from archaea to medusae is the prevailing condition in marine ecosystems. Such nutrient-limitation will shift the physiological state in these organisms with accompanying changes in their physiology and biochemistry. Here, we review our laboratory’s progress in documenting these changes associated with starvation in a range of marine organisms. Specifically, we focused on respiration, ammonium excretion, CO2 production, RQ, respiratory ETS activity, isocitrate dehydrogenase and glutamate dehydrogenase activity in the mysid, Leptomysis lingvura, a dinoflagellate, Oxyrrhis marina and two bacteria, Vibrio natriegens, and Pseudomonas nautica. In all cases, with starvation, the respiration and the ammonium excretion rates decreased, the RQ increased, respiratory ETS activity, IDH activity and glutamate dehydrogenase activity remained relatively constant, but the ratios of the enzyme activities to their associated physiological rates, increased. Incorporation of these new findings should improve the predictions of ecosystem models.