Sequential iron extraction in acidic and non-acidic tundra, Toolik, Alaska (2021)

The goal of this study was to measure the various species of iron in soils with differing soil pH and soil moisture conditions. Soils were collected over the summer of 2021 along two tundra hillslopes (one acidic and one non-acidic) near Toolik Lake. Each study hillslope had three sites with soil moisture conditions delineated as Dry, Mesic, and Wet, with three replicate 5 x 5 meter (m) plots at each site. Soil samples were collected from each replicate plot at three sampling events over the summer of 2021. Soils were extracted using a 2-inch stainless steel corer and were frozen upon return from the field. The sampled soils were separated by horizon and then underwent a sequential iron extraction to measure iron associated with soil organic matter, poorly crystalline forms of iron, and crystalline forms of iron.