Temperature and the chemical composition of poikilothermic organisms

Abstract

Summary 1.Temperature strongly affects virtually all biological rate processes, including many central to organismal fitness such as growth rate. A second factor related to growth rate is organismal chemical composition, especially C : N : P stoichiometry. This association arises because high rates of growth require disproportionate investment in N-and P-rich biosynthetic cellular structures. Here the extent to which these factors interact is examined -does acclimation temperature systematically affect organismal chemical composition? 2. A literature survey indicates that cold-acclimated poikilotherms contain on average 30-50% more nitrogen [N], phosphorus [P], protein and RNA than warm-exposed conspecifics. The primary exception was bacteria, which showed increases in RNA content but no change in protein content at cold temperatures. 3. Two processes -changes in nutrient content (or concentration) and in organism size -contribute to the overall result. Although qualitatively distinct, both kinds of change lead to increased total catalytic capacity in cold-exposed organisms. 4. Temperature-driven shifts in nutrient content of organisms are likely to resonate in diverse ecological patterns and processes, including latitudinal and altitudinal patterns of nutrient content, foraging decisions by organisms living in strong temperature gradients, and patterns of biodiversity.

The functional role of planktonic mixotrophs in altering seston stoichiometry

“…With increasing temperature, algal C:nutrient ratios have been shown to increase, either due to enhanced carbon fixation per unit resource (e.g. Moorthi et al 2016) or due to decreasing intracellular N and P concentrations based on enhanced efficiency of RNA (requiring P) and proteins (requiring N) in biochemical reactions (Woods et al 2003). Also, the contribution of photosynthesis and phagotrophy varies with temperature in mixo trophs (Wilken et al 2013, Princiotta et al 2016, which presumably also alters intracellular nutrient stoichiometry.…”

Maximizing growth rate at low temperatures: RNA:DNA allocation strategies and life history traits of Arctic and temperate Daphnia

“…On the other hand, higher absolute levels of enzymes would increase reaction rates at all temperatures. In support of this, a literature survey found that cold-acclimated ectotherms contained higher cell-specific levels of phosphorus (P) and rRNA than warm-exposed conspecifics (Woods et al 2003). This is probably due to reduced efficiency of protein synthesis at low temperatures, i.e.…”

“…A crucial question is how animals cope with the need for high growth rates due to short seasons in cold areas, i.e. how can ectothermic animals maintain relatively high rates of growth and metabolism despite living at low temperatures (Woods et al 2003). Two hypotheses may explain thermal adaptations in cellular processes: structural changes of enzymes that increase the rate of reaction at low temperature (cold adaptation, Hochachka and Somero 1973), or higher absolute levels of enzymes in cells in support of overall reaction rates (Adamowicz et al 2002).…”

N–P stoichiometry in soil and leaves of Pinus massoniana forest at different stand ages in the subtropical soil erosion area of China

“…The elements carbon (C), nitrogen (N), and phosphorus (P) are the fundamental chemical elements of an organism. The stoichiometry of an organism is closely related to the important ecological processes such as ecosystem species composition and diversity, adaptation of organisms to environmental stress, and interspecific relationships (Venterink et al 2003;Woods et al 2003;Aerts et al 2003;Güsewell et al 2005).…”