Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps
Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps
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DOI：
10.5194/bg-11-6573-2014
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发表时间：
2014-01-01
期刊：
影响因子：
4.9
通讯作者：
Kuhry, P.
中科院分区：
文献类型：
--
作者：
Hugelius, G.;Strauss, J.;Kuhry, P.
北部环极地永久冻土区的土壤和其他松散沉积物储存了大量的土壤有机碳（SOC）。该 SOC 可能容易受到土壤变暖和永久冻土融化后重新动员的影响，但 SOC 储量估计受到很大限制，并且缺乏定量误差估计。本研究提出了对永久冻土 SOC 储量的修订估计，包括土壤 0-3 m 深度范围以及主要河流三角洲沉积物以及西伯利亚和阿拉斯加耶多马地区深度超过 3 m 的沉积物的定量不确定性估计。与之前的研究相比，修订后的估计基于更大的数据库。尽管如此，有证据表明区域数据仍存在巨大差距。对于高北极地区和沉积覆盖层较薄的自然地理区域（山脉、高地和高原）的土壤以及三角洲和耶多马地区 3 米以下沉积物的估计仍然受到特别严格的限制。虽然修订后的 SOC 库存的某些组成部分与之前报告的该地区的数量相似，但其他组成部分存在重大差异，包括常年冻结的 SOC 的比例。根据区域土壤图进行升级，对于 0-0.3 和 0-1 m 土壤深度，估计的永久冻土区 SOC 储量分别为 217 +/- 12 和 472 +/- 27 Pg（+/- 95% 置信区间）。 0-3m 土壤中的 SOC 储存量估计为 1035 +/- 150 Pg。其中，34 +/- 16 PgC 储存在高北极地区发育不良的土壤中。根据一般计算，北极主要河流的三角洲冲积层表层土壤 3m 以下的 SOC 储存量估计为 91 +/- 52 Pg。在 Yedoma 地区，3 米深度以下的 SOC 储量估计为 181 +/- 54 Pg，其中 74 +/- 20 Pg 储存在完整的 Yedoma（晚更新世冰和富含有机物的粉质沉积物）中，其余部分储存在重新冻结的热岩溶沉积物中。永久冻土区的总估计 SOC 存储量类似于 1300 Pg，不确定性范围类似于 1100 至 1500 Pg。其中，大约 500 Pg 位于非永久冻土土壤中，在活动层或更深的塔里克斯季节性解冻，而大约 800 Pg 则为常年冻结。与之前的估计相比，这意味着估计的常年冻结 SOC 库存大幅降低了 300 Pg。
Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of permafrost SOC stocks, including quantitative uncertainty estimates, in the 0-3m depth range in soils as well as for sediments deeper than 3m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. Revised estimates are based on significantly larger databases compared to previous studies. Despite this there is evidence of significant remaining regional data gaps. Estimates remain particularly poorly constrained for soils in the High Arctic region and physiographic regions with thin sedimentary overburden (mountains, highlands and plateaus) as well as for deposits below 3mdepth in deltas and the Yedoma region. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are substantial differences in other components, including the fraction of perennially frozen SOC. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 +/- 12 and 472 +/- 27 Pg for the 0-0.3 and 0-1 m soil depths, respectively (+/- 95% confidence intervals). Storage of SOC in 0-3m of soils is estimated to 1035 +/- 150 Pg. Of this, 34 +/- 16 PgC is stored in poorly developed soils of the High Arctic. Based on generalized calculations, storage of SOC below 3m of surface soils in deltaic alluvium of major Arctic rivers is estimated as 91 +/- 52 Pg. In the Yedoma region, estimated SOC stocks below 3mdepth are 181 +/- 54 Pg, of which 74 +/- 20 Pg is stored in intact Yedoma (late Pleistocene ice-and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits. Total estimated SOC storage for the permafrost region is similar to 1300 Pg with an uncertainty range of similar to 1100 to 1500 Pg. Of this, similar to 500 Pg is in non-permafrost soils, seasonally thawed in the active layer or in deeper taliks, while similar to 800 Pg is perennially frozen. This represents a substantial similar to 300 Pg lowering of the estimated perennially frozen SOC stock compared to previous estimates.