КОНЦЕПЦІЯ ЕНЕРГЕТИЧНОГО БАЛАНСУ В ДОДАТКУ ДО МІКРОБНОЇ ХАРЧОВОЇ МЕРЕЖІ ВОДНИХ ЕКОСИСТЕМ

A revision of the current paradigm of the energy flow in aquatic ecosystems (and, in particular, microplankton) is required as the latter is based on a few false assumptions, namely: (i) the energy flow is coupled exceptionally to trophic processes (“trophic energy flow”); (ii) aerobic respiration is the only catabolic process in the oxic water column; (iii) intracellular metabolism is the only source of heat energy dissipated by water sample. Almost no progress in developing the energy flow paradigm was observed for the last decades, likely owing to imperfections in the methodology for measuring the energy flow directly as heat dissipation. There is a considerable gap in the data on in situ physiological activity of planktonic microorganisms, which is filled with indirect estimates of their metabolic rates approximated from material flows (like production). This prevalent approach provides no valuable information on the real metabolic rate but produces its fallacious estimates as the net growth efficiency (K2) is not actually measured in the same experiment. In microplankton studies, an extensive approach prevails in which integral respiration mea-surements are favored over estimates of metabolic fluxes per cell, biovolume and biosurface. This limits our knowledge of physiological activity of planktonic microorganisms and, besides, deprives the researcher an opportunity to verify the results obtained. Doubt has been recently thrown on the validity of the respirometric estimates of the energy flows in aquatic ecosystems and, consequently, there exist a demand on alternative methodological approaches to solve the problem. Applying nanocalorimetry in the field of hydrobiology looks promising as a highly sensitive method for measuring directly the heat dissipation by native microplankton, without any cell pre-concentration. Modern knowledge of the viral loop, physiology of ultramicrobacteria, and bacteria-mediated extracellular hydrolysis of biopolymers have to be taken into account to calculate detailed energy budget of microplankton.