Plant uptake offsets silica release from a large Arctic tundra wildfire

Rapid climate change at high latitudes is projected to increase wildfire extent in tundra ecosystems by up to five-fold by the end of the century. Tundra wildfire could alter terrestrial silica (SiO2) cycling by restructuring surface vegetation and by deepening the seasonally-thawed active layer. These changes could influence the availability of silica in terrestrial permafrost ecosystems and alter lateral exports to downstream marine waters, where silica is often a limiting nutrient. In this context, we investigated the long-term effects of the largest Arctic tundra fire in recent times on plant and peat amorphous silica content and dissolved silica concentration in streams. Ten-years after the fire, vegetation in burned areas had 73% more silica in aboveground biomass compared to adjacent, unburned areas. This increase in plant silica was attributable to significantly higher plant silica concentration in bryophytes and increased prevalence of silica-rich gramminoids in burned areas. T...高纬度地区的快速气候变化预计将在本世纪末使苔原（tundra）生态系统的野火蔓延范围扩大至多五倍。苔原野火可通过重塑地表植被、加深季节解冻活动层来改变陆地二氧化硅（SiO₂）循环。此类变化可能会影响陆地永久冻土（permafrost）生态系统中二氧化硅的可利用性，并改变向下游海域的侧向输出，而二氧化硅通常是该处的限制性营养盐。在此背景下，本研究针对近代以来规模最大的北极苔原野火，探究其对植物、泥炭非晶态二氧化硅含量以及溪流中溶解态二氧化硅浓度的长期影响。野火发生十年后，过火区域植被的地上生物量中二氧化硅含量较邻近未过火区域高出73%。植物二氧化硅含量的这一提升，源于过火区域苔藓植物的二氧化硅浓度显著升高，以及富二氧化硅禾草类植物的占比增加。T...