USA

Soil Science

Coastal erosion is a growing problem in northern Alaska. The erosion rate appears to be increasing and threatens human development and infrastructure. Erosion of coastal peat soils in Alaska may be part of a positive feedback cycle for climate change caused by a net release of carbon (C). Erosion along Alaska’s Beaufort Sea Coast annually introduces substantial quantities of largely-undecomposed organic matter into the Arctic Ocean. To understand and make predictions regarding the effects of erosion on soil and permafrost dynamics inland from the coast, three representative sites were chosen for study: Elson Lagoon, Prudhoe Bay, and Barter Island. A total of 10 transects, 100m long, were examined for morphological, physical, and chemical properties, and thermokarst extent at the three sites was quantified. Soil profiles and permafrost cores revealed organic materials extending 1.8m below the surface. The permafrost at the three sites was composed of 10% to 40% wedge ice and the moisture content of the soil ranged from 2% to 80%. Total C content averaged 10% in the active layer and 35% in the frozen soil. Total N was less than 2% throughout the soil profiles. Soil pH and EC showed a relationship between mineral soils at depth and increased values. There was no correlation between soil properties and distance from shore and soils were not drier closer to shore. The erosion rate at the three sites is so fast that there is not time enough for any significant changes in soil properties to occur.