In contrast to good knowledge of dissolved organic matter (DOM) adsorption on mineral soils in temperate climate, the behavior of DOM in frozen mineral horizons located under peat soils of permafrost-affected regions remains poorly characterized. Yet, these regions contain sizeable and potentially highly labile pools of organic (peat) carbon (C) that may migrate downwards across mineral layers in case of massive thaw in frozen peatlands induced by on-going climate warming. To quantify these pools and the lability of DOM in permafrost peat soils, we performed experiments focusing on dissolved organic carbon (DOC) desorption from, and adsorption onto, mineral horizons (iron-poor and iron-rich sands as well as silt loam) from the largest frozen peatland in the world, the Western Siberia Lowland (WSL). Desorbed DOC ranged between 0.1 and 0.6 mg C g_soil⁻¹ depending on type of mineral substrate. The adsorption of peat leachate DOM ranged between 0.1 and 0.5 mg C g_soil⁻¹ being highest in Al-Fe-rich mineral horizons.

Field measurements of C pools in peat and underlying mineral horizons over 1 m depth in the discontinuous permafrost zone yielded 47 and 15 kg C m⁻², respectively. The organic carbon (OC) adsorption capacity of the 1 m – thick mineral layers represented <2% of total amount of OC containing in the 1 m – thick peat layer. However, this adsorption capacity is comparable to the amount of DOC that can be leached from overlaying peat horizons (18%). On average, out of 1.38 ± 0.13 kg C m⁻² capable of being initially released from the upper 0–100 cm of peat, 0.25 ± 0.19 kg C m⁻² can be adsorbed by the underlying 100–200 cm of Fe- and Al-rich sands and clays. The remaining 1.13 kg C m⁻² can be exported to lakes and rivers. Therefore, DOC released during peat thaw in upper soil horizons in permafrost regions can be sizably attenuated via adsorption on mineral layers. This should be taken into account when modeling the feedback of permafrost thaw on C export and CO₂ emissions.

与温带气候下矿质土壤上溶解有机质 (DOM) 吸附的良好知识相比，DOM 在位于受多年冻土影响地区泥炭土下的冻结矿物层中的行为仍然缺乏表征。然而，这些地区包含大量且潜在高度不稳定的有机（泥炭）碳 (C) 池，如果持续的气候变暖导致冰冻泥炭地大规模解冻，这些碳池可能会向下迁移穿过矿物层。为了量化这些池和永久冻土泥炭土中 DOM 的不稳定性，我们进行了实验，重点是溶解有机碳 (DOC) 从来自世界上最大的冰冻泥炭地，西西伯利亚低地 (WSL)。解吸 DOC 介于 0.1 和 0.6 mg C g 之间_土壤^-1取决于矿物基质的类型。泥炭渗滤液 DOM 的吸附范围在 0.1 和 0.5 mg C g_土壤^-1之间，在富含 Al-Fe 的矿物层中最高。

在不连续的永久冻土带中超过 1 m 深度的泥炭和下伏矿物层中的 C 池的现场测量分别产生了 47 和 15 kg C m ^-2。1 m 厚矿物层的有机碳 (OC) 吸附能力占 1 m 厚泥炭层中 OC 总量的 <2%。然而，这种吸附能力与可以从覆盖的泥炭层中浸出的 DOC 量（18%）相当。平均而言，在最初能够从上部 0-100 cm 泥炭释放的 1.38 ± 0.13 kg C m ^{-2 中}，0.25 ± 0.19 kg C m ^-2可以被下面的 100-200 cm Fe- 和富含铝的砂和粘土。剩余 1.13 kg C·m ^-2可以出口到湖泊和河流。因此，在多年冻土地区上层土壤中泥炭解冻过程中释放的 DOC 可以通过吸附在矿物层上而大大减弱。在模拟永久冻土融化对 C 输出和 CO ₂排放的反馈时，应考虑到这一点。