Dispersed ice of permafrost peatlands represents an important source of labile carboxylic acids, nutrients and metals

•Organic and inorganic nutrients in peat porewaters and ice.•Organic acids and trace metals in aqueous leachates of freeze-dried peat.•Leachable stock of nutrients in frozen peat strongly exceeds that in thawed layer.•Leachates of 100 gpeat L-1 are suitable for approximating natural porewater and ice.