Temperature differentially affects feeding, metabolism, and biosynthesis in larval forms

At the level of a whole organism, thermal stress is known to elicit biological responses that are energetically costly. Less understood, however, are how specific processes respond to temperature. Information on the latter is required to predict physiological limits, based on an understanding of biological uncoupling of essential processes that may have different sensitivities to temperature. We studied larval forms of echinoderms (Lytechinus pictus; Strongylocentrotus purpuratus) reared under different temperatures to measure thermal sensitivities of feeding, respiration, biosynthesis, and excretion within and across species. Protein synthesis is more sensitive to temperature increase than respiration and other processes measured. At the level of the whole-organism, this decoupling of ATP demand to support protein synthesis, versus ATP production from respiration, results in a substantial change in the proportional allocation of ATP to protein synthesis with temperature. Understanding these biochemical strategies provide insights into predictions of whole-organism tolerances to a warming ocean.