Soils and Cryoturbation in Moist Nonacidic and Acidic Tundra in the Kuparuk River Basin, Arctic Alaska, U.S.A.

Abstract

We compared 22 pedons derived from silty materials in moist nonacidic tundra (MNT) and moist acidic tundra (MAT) in the arctic foothills of the 9200-km² Kuparuk River basin in northern Alaska. Soils in MNT have thinner organic horizons, a significantly thicker active layer, and greater cryoturbation than soils in MAT. The quantities of clay and organic-plus-inorganic C in the upper 100 cm are comparable; however, soils in MNT have significantly greater amounts of extractable Ca, Mg, and sum of base cations and significantly lower amounts of exchangeable acidity and Al than soils in MAT. Tissues from forbs, sedges, and woody shrubs in MNT have two to three times as much Ca as the same or similar species in MAT. The area of nonsorted circles was significantly greater in MNT (9.6%) than in MAT (0.9%). Although the existence of nonacidic tundra in the Arctic has been known for some time, its origin and distribution have not been fully explained. Our data link soil and vegetation properties and indicate that cryoturbation plays an important role in maintaining MNT in arctic Alaska.