The role of food chain balance and common nutritional environment in interspecific allometric scaling of unicellular organisms

One of the major characteristics of living organisms is metabolic rate the amount of energy produced per unit time. When the size of organisms increases, the metabolic rate increases slower than organisms' mass, which has important implications for the evolutionary and ontogenetic development. Here, we study the fundamental causes of this phenomenon on the basis of metabolic properties of unicellular organisms (Amoeba Proteus, fission yeast S. pombe, E. coli, B. subtilis, Staphylococcus). We use a new approach for finding metabolic characteristics of unicellular organisms. The study discovered that the metabolic properties and allometric scaling of unicellular organisms are defined by at least two primary factors. One is the acquisition of nutrients through the surface in a common nutritional environment, which forms the base part of 2/3 of an allometric exponent. The other factor is a regular increase of nutrient influx per unit surface when one ascends the food chain and organisms' mass increases. Accounting for the increase of nutrient influx and its variations, we obtained allometric exponents close to values obtained in experiments. We conjecture that the metabolic properties of living organisms are much influenced by the requirement of a balanced state of an entire food chain.