UPMC, UMR 7618 Bioemco, 46 Rue d'Ulm, F-75230 Paris Cedex 05, France.
Ecology. 2010 Oct;91(10):2850-61. doi: 10.1890/09-1968.1.
Understanding how ecosystems store or release carbon is one of ecology's greatest challenges in the 21st century. Organic matter covers a large range of chemical structures and qualities, and it is classically represented by pools of different recalcitrance to degradation. The interaction effects of these pools on carbon cycling are still poorly understood and are most often ignored in global-change models. Soil scientists have shown that inputs of labile organic matter frequently tend to increase, and often double, the mineralization of the more recalcitrant organic matter. The recent revival of interest for this phenomenon, named the priming effect, did not cross the frontiers of the disciplines. In particular, the priming effect phenomenon has been almost totally ignored by the scientific communities studying marine and continental aquatic ecosystems. Here we gather several arguments, experimental results, and field observations that strongly support the hypothesis that the priming effect is a general phenomenon that occurs in various terrestrial, freshwater, and marine ecosystems. For example, the increase in recalcitrant organic matter mineralization rate in the presence of labile organic matter ranged from 10% to 500% in six studies on organic matter degradation in aquatid ecosystems. Consequently, the recalcitrant organic matter mineralization rate may largely depend on labile organic matter availability, influencing the CO2 emissions of both aquatic and terrestrial ecosystems. We suggest that (1) recalcitrant organic matter may largely contribute to the CO2 emissions of aquatic ecosystems through the priming effect, and (2) priming effect intensity may be modified by global changes, interacting with eutrophication processes and atmospheric CO2 increases. Finally, we argue that the priming effect acts substantially in the carbon and nutrient cycles in all ecosystems. We outline exciting avenues for research, which could provide new insights on the responses of ecosystems to anthropogenic perturbations and their feedbacks to climatic changes.
理解生态系统如何储存或释放碳是 21 世纪生态学面临的最大挑战之一。有机物质涵盖了广泛的化学结构和性质，通常以不同抗降解能力的库来表示。这些库对碳循环的相互作用效应仍未被充分理解，并且在全球变化模型中通常被忽略。土壤科学家已经表明，易降解有机物质的输入往往会增加，并且经常使更难降解的有机物质的矿化作用增加一倍。这种现象被称为激发效应，最近重新引起了人们的兴趣，但并未跨越学科的界限。特别是，研究海洋和大陆水生生态系统的科学界几乎完全忽略了激发效应现象。在这里，我们收集了一些论据、实验结果和野外观察结果，这些结果强烈支持这样一种假设，即激发效应是一种普遍现象，发生在各种陆地、淡水和海洋生态系统中。例如，在存在易降解有机物质的情况下，水生生态系统中难降解有机物质矿化率的增加幅度在六项有机物质降解研究中从 10%到 500%不等。因此，难降解有机物质的矿化率可能在很大程度上取决于易降解有机物质的可用性，从而影响水生和陆地生态系统的 CO2 排放。我们提出（1）通过激发效应，难降解有机物质可能在很大程度上促进水生生态系统的 CO2 排放，以及（2）激发效应的强度可能会受到全球变化的影响，与富营养化过程和大气 CO2 增加相互作用。最后，我们认为激发效应在所有生态系统的碳和养分循环中都起着重要作用。我们概述了令人兴奋的研究途径，这可能为生态系统对人为干扰的反应及其对气候变化的反馈提供新的见解。
