Northern peatland carbon stocks and dynamics: a review
Northern peatland carbon stocks and dynamics: a review
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DOI：
10.5194/bg-9-4071-2012
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发表时间：
2012-10
期刊：
影响因子：
4.9
通讯作者：
Zicheng Yu
中科院分区：
文献类型：
--
作者：
Zicheng Yu
抽象的。泥炭地在生物圈中含有大量的地下碳(C)，它们的动态对全球碳循环具有重要影响。然而，在C库存估计中仍然存在很大的不确定性，并且对跨时间尺度的C动态的理解很差。在这里，我回顾了文献中不同的C储量估计方法和相关的不确定性，并在文献回顾的基础上，我对北部泥炭地碳储量和不确定性的最佳估计是500±100亿吨C(GTC)。所有方法的最大不确定性来源是缺乏或不充分的数据，包括深度、体积密度和碳累积数据，特别是来自世界上大型泥炭地的数据。文中还讨论了改进泥炭碳储量估算的几种方法，包括按地区估算碳储量和进一步利用广泛可用的基础泥炭年龄。泥炭地碳储量随时间的变化，根据泥炭苔藓孢子数据和泥炭沉积记录估计，在全新世期间显示出不同的模式，我认为基于孢子的方法低估了泥炭地早期历史上的丰度。利用泥炭累积数据考虑长期的泥炭分解，可以通过泥炭地或净(生态系统)碳平衡(NECB)来估计净碳固定率，这表明超过一半的泥炭碳(>；270GTC)是在7000年前的全新世期间被固定的。5个泥炭地的当代碳通量研究表明，在过去十年中，NECB要大得多(32±7.8(S.E.)GCm−2yr-1)，而不是过去7000年(∼11g Cm−2yr-1)，根据北部泥炭地的泥炭记录模拟。这种差异突出表明，迫切需要碳累积数据和过程理解，特别是在十年和百年时间尺度上，这将弥合当前的知识差距，并促进对所有时间尺度上的NECB进行比较。
Abstract. Peatlands contain a large belowground carbon (C) stock in the biosphere, and their dynamics have important implications for the global carbon cycle. However, there are still large uncertainties in C stock estimates and poor understanding of C dynamics across timescales. Here I review different approaches and associated uncertainties of C stock estimates in the literature, and on the basis of the literature review my best estimate of C stocks and uncertainty is 500 ± 100 (approximate range) gigatons of C (Gt C) in northern peatlands. The greatest source of uncertainty for all the approaches is the lack or insufficient representation of data, including depth, bulk density and carbon accumulation data, especially from the world's large peatlands. Several ways to improve estimates of peat carbon stocks are also discussed in this paper, including the estimates of C stocks by regions and further utilizations of widely available basal peat ages. Changes in peatland carbon stocks over time, estimated using Sphagnum (peat moss) spore data and down-core peat accumulation records, show different patterns during the Holocene, and I argue that spore-based approach underestimates the abundance of peatlands in their early histories. Considering long-term peat decomposition using peat accumulation data allows estimates of net carbon sequestration rates by peatlands, or net (ecosystem) carbon balance (NECB), which indicates more than half of peat carbon (> 270 Gt C) was sequestrated before 7000 yr ago during the Holocene. Contemporary carbon flux studies at 5 peatland sites show much larger NECB during the last decade (32 ± 7.8 (S.E.) g C m−2 yr–1) than during the last 7000 yr (∼ 11 g C m−2 yr–1), as modeled from peat records across northern peatlands. This discrepancy highlights the urgent need for carbon accumulation data and process understanding, especially at decadal and centennial timescales, that would bridge current knowledge gaps and facilitate comparisons of NECB across all timescales.