Department of Geography, College of Science, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
Department of Biosciences, College of Science, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
Sci Rep. 2017 Sep 11;7(1):11233. doi: 10.1038/s41598-017-10455-2.
Pyrogenic carbon (PyC), produced naturally (wildfire charcoal) and anthropogenically (biochar), is extensively studied due to its importance in several disciplines, including global climate dynamics, agronomy and paleosciences. Charcoal and biochar are commonly used as analogues for each other to infer respective carbon sequestration potentials, production conditions, and environmental roles and fates. The direct comparability of corresponding natural and anthropogenic PyC, however, has never been tested. Here we compared key physicochemical properties (elemental composition, δC and PAHs signatures, chemical recalcitrance, density and porosity) and carbon sequestration potentials of PyC materials formed from two identical feedstocks (pine forest floor and wood) under wildfire charring- and slow-pyrolysis conditions. Wildfire charcoals were formed under higher maximum temperatures and oxygen availabilities, but much shorter heating durations than slow-pyrolysis biochars, resulting in differing physicochemical properties. These differences are particularly relevant regarding their respective roles as carbon sinks, as even the wildfire charcoals formed at the highest temperatures had lower carbon sequestration potentials than most slow-pyrolysis biochars. Our results challenge the common notion that natural charcoal and biochar are well suited as proxies for each other, and suggest that biochar's environmental residence time may be underestimated when based on natural charcoal as a proxy, and vice versa.
热解碳（PyC），无论是自然产生的（野火炭）还是人为产生的（生物炭），都因其在多个学科中的重要性而被广泛研究，包括全球气候动力学、农业学和古科学。木炭和生物炭通常被用作彼此的模拟物，以推断各自的碳封存潜力、生产条件以及环境角色和命运。然而，相应的天然和人为 PyC 的直接可比性从未得到过检验。在这里，我们比较了两种相同的原料（松林地表和木材）在野火炭化和慢速热解条件下形成的 PyC 材料的关键物理化学性质（元素组成、δC 和多环芳烃特征、化学稳定性、密度和孔隙率）和碳封存潜力。野火炭在更高的最高温度和氧气可用性下形成，但加热时间比慢速热解生物炭短得多，导致物理化学性质不同。这些差异对于它们各自作为碳汇的作用尤其重要，因为即使在最高温度下形成的野火炭的碳封存潜力也低于大多数慢速热解生物炭。我们的结果挑战了一个常见的观点，即天然木炭和生物炭是很好的替代品，这表明当基于天然木炭作为替代品时，生物炭的环境停留时间可能被低估了，反之亦然。
