Salt Extractable Organic Matter Carbon in Alaskan Permafrost Region Soils

• Main Author: Sharp, Callie
• Format: Text
• Language: unknown
• Published: Digital USD 2018
• Subjects: permafrost; Alaska
• Online Access: https://digital.sandiego.edu/osp-researchweek/2018/ccurc/65; https://digital.sandiego.edu/cgi/viewcontent.cgi?article=1118&context=osp-researchweek

Permafrost, soil frozen for two or more consecutive years, is common in the northern circumpolar region. The soils in the permafrost region are estimated to hold over two times more carbon than the amount contained in the atmosphere. This region is highly susceptible to the effects of climate change, specifically to the thawing of permafrost due to global warming. When permafrost thaws and other soils in this cold region are subjected to warming, microbial activity increases, decomposing soil organic matter into the greenhouse gases carbon dioxide and methane. The release of these gases into the atmosphere can potentially begin a positive feedback loop that could speed up the rate of climate change. The goals of this project were to estimate the amount of bioavailable organic matter in the permafrost regions of Alaska, USA, to use salt extractable organic matter (SEOM) as a proxy for the most readily decomposable organic matter, and to look for trends within this data related to various subdivisions, such as land cover and horizon type. SEOM analysis was performed through K2SO4 extraction, UV spectroscopy, and a Shimadzu total organic carbon analyzer. The study found that while there is a higher proportion of bioavailable carbon in mineral soils than organic soils, organic soil SEOM appears to be more labile than that of mineral soils. Additionally, SEOM total organic carbon is greater in forest soils than wetland soils, and this difference is primarily driven by the organic soils in each area.