Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
Environ Sci Technol. 2010 Jun 1;44(11):4076-82. doi: 10.1021/es903685j.
Large quantities of soil organic carbon in Arctic permafrost zones are becoming increasingly unstable due to a warming climate. High temperatures and substantial rainfall in July 2007 in the Canadian High Arctic resulted in permafrost active layer detachments (ALDs) that redistributed soils throughout a small watershed in Nunavut, Canada. Molecular biomarkers and NMR spectroscopy were used to measure how ALDs may lead to microbial activity and decomposition of previously unavailable soil organic matter (SOM). Increased concentrations of extracted bacterial phospholipid fatty acids (PLFAs) and large contributions from bacterial protein/peptides in the NMR spectra at recent ALDs suggest increased microbial activity. PLFAs were appreciably depleted in a soil sample where ALDs occurred prior to 2003. However an enrichment of bacterial derived peptidoglycan was observed by (1)H-(13)C heteronuclear multiple quantum coherence (HMQC) and (1)H diffusion edited (DE) NMR and enhanced SOM degradation was observed by (13)C solid-state NMR. These data suggest that a previous rise in microbial activity, as is currently underway at the recent ALD site, led to degradation and depletion of labile SOM components. Therefore, this study indicates that ALDs may amplify climate change due to the release of labile SOM substrates from thawing High Arctic permafrost.
由于气候变暖，北极永久冻土带的大量土壤有机碳正变得越来越不稳定。2007 年 7 月，加拿大北极地区的高温和大量降雨导致永冻层活动层分离（ALD），这些分离将土壤重新分布在加拿大努纳武特的一个小流域中。分子生物标志物和 NMR 光谱被用来测量 ALD 如何导致微生物活动和以前无法获得的土壤有机质（SOM）的分解。在最近的 ALD 中，提取的细菌磷脂脂肪酸（PLFA）浓度增加，NMR 光谱中细菌蛋白质/肽的大量贡献表明微生物活性增加。在 2003 年之前发生 ALD 的土壤样本中，PLFA 明显耗尽。然而，通过（1）H-（13）C 异核多量子相干（HMQC）和（1）H 扩散编辑（DE）NMR 观察到细菌衍生肽聚糖的富集，并且通过（13）C 固态 NMR 观察到 SOM 降解增强。这些数据表明，目前在最近的 ALD 地点进行的微生物活性增加导致了易失性 SOM 成分的降解和消耗。因此，本研究表明，由于高北极永久冻土带融化释放易失性 SOM 底物，ALD 可能会放大气候变化。
