WOODS, HA*; HOBBIE, SE; MAKINO, W; COTNER, J; HARRISON, JF; ELSER, JJ: Temperature shifts cause systematic changes in biochemical composition of poikilothermic organisms

We surveyed the literature to explore the extent to which acclimation temperature influences the nitrogen (N) and phosphorus (P) and of N-rich (protein) and P-rich (RNA) biochemicals in poikilothermic organisms, including bacteria, yeast, algae, animals, and terrestrial plants. We focused on N and P biochemistry because these elements are major constituents of key cellular structures and because they are important nutrients in ecological processes. The currencies of N and P thus provide a natural way to trace temperature’s effects across levels of biological organization. Organisms in the literature survey were exposed to a mean temperature difference of about 13 �C. On average, those exposed to cold showed ~27% higher protein or N content and ~48% higher RNA or P content than did conspecifics exposed to warm temperatures. Additional analyses revealed that this shift occurred in all broad taxonomic groupings, except possibly in bacteria. Altogether, these results identify biologically significant shifts in chemical composition induced by temperature and indicate that these shifts are a pervasive feature of poikilothermic biology. Although shifts in composition may stem from multiple causes, the simplest general explanation is that organisms in the cold increase the concentrations of enzymes and ribosomes to offset or exploit shifts in relative rates of diffusion and reaction of biochemicals. We suggest that changes in the composition of individual organisms may affect species interactions and contribute to ecosystem-level patterns in C:N:P stoichiometry across latitudinal and altitudinal temperature gradients.