López-Urrutia Angel, Morán Xosé Anxelu G
Centro Oceanográfico de Gijón, Instituto Español de Oceanografía, Camín de L'Arbeyal, s/n, Xixón, Asturies, E-33212 Spain.
Ecology. 2007 Apr;88(4):817-22. doi: 10.1890/06-1641.
Our view of the effects of temperature on bacterial carbon fluxes in the ocean has been confounded by the interplay of resource availability. Using an extensive compilation of cell-specific bacterial respiration (BRi) and production (BPi), we show that both physiological rates respond to changing temperature in a similar manner and follow the predictions of the metabolic theory of ecology. Their apparently different temperature dependence under warm, oligotrophic conditions is due to strong resource limitation of BP, but not of BRi. Thus, and despite previous preconception, bacterial growth efficiency (BGE = BPi/[BPi + BRi]) is not directly regulated by temperature, but by the availability of substrates for growth. We develop simple equations that can be used for the estimation of bacterial community metabolism from temperature, chlorophyll concentration, and bacterial abundance. Since bacteria are the greatest living planktonic biomass, our results challenge current understanding of how warming and shifts in ecosystem trophic state will modify oceanic carbon cycle feedbacks to climate change.
我们对温度对海洋中细菌碳通量影响的看法一直因资源可用性的相互作用而混淆。通过广泛收集特定细胞的细菌呼吸（BRi）和生产（BPi）数据，我们表明这两种生理速率对温度变化的响应方式相似，并遵循生态代谢理论的预测。在温暖、贫营养条件下它们明显不同的温度依赖性是由于BP受到强烈的资源限制，而BRi则不受此限制。因此，尽管之前有先入之见，但细菌生长效率（BGE = BPi / [BPi + BRi]）并非直接受温度调节，而是受生长底物可用性的调节。我们开发了简单的方程，可用于根据温度、叶绿素浓度和细菌丰度估算细菌群落代谢。由于细菌是最大的活浮游生物量，我们的结果挑战了当前对变暖和生态系统营养状态变化将如何改变海洋碳循环对气候变化反馈的理解。
