Iron-Phosphorus sediment incubation experiment in Stordalen Mire, Abisko, Sweden (2019)

Phosphorus limits primary productivity in many (Sub-)Arctic ecosystems and may constrain biological carbon sequestration. Iron (III) oxides strongly bind phosphate in soils but can dissolve under flooded, reducing conditions induced by permafrost thaw and ground collapse. The ability for iron to regulate phosphate storage and solubility in thawing permafrost landscapes remains unclear. Here, iron-rich sediments containing iron oxides and organic-bound iron were incubated with or without added phosphate in soils along a permafrost thaw gradient to evaluate how iron-phosphate associations respond to thaw-induced redox shifts. Iron oxides partially dissolved and released sorbed phosphate when incubated in soils underlain by degraded permafrost. Iron complexed by organic matter remained stable but provided no phosphate binding capacity. Our study demonstrates that the capacity for iron oxides to immobilize and retain phosphate in permafrost peatlands decreases with permafrost thaw. This dataset includes soil redox potential measurements and soil water chemistry that provide the context for understanding iron mineral transformation and associations with phosphorus.

磷是多数（亚）北极生态系统初级生产力的限制因子，或可制约生物固碳过程。三价铁氧化物可强力结合土壤中的磷酸盐，但在由永久冻土（permafrost）融化与地面塌陷引发的淹水还原环境中可发生溶解。在融化中的冻土景观中，铁调控磷酸盐储存与溶解度的能力仍不明晰。本研究沿冻土融化梯度设置土壤培养实验，将含三价铁氧化物与有机结合态铁的富铁沉积物分别在添加与不添加磷酸盐的条件下进行培养，以探究铁-磷酸盐结合体对融化诱导的氧化还原变化的响应机制。在发育于退化永久冻土之上的土壤中培养时，三价铁氧化物会部分溶解并释放其所吸附的磷酸盐。经有机质络合的铁则保持稳定，但无结合磷酸盐的能力。本研究表明，在冻土泥炭地中，三价铁氧化物固定与留存磷酸盐的能力随冻土融化程度加剧而减弱。本数据集包含土壤氧化还原电位测定数据与土壤水化学数据，可为解析铁矿物转化过程及其与磷的结合关系提供背景支撑。