Expedition to Iskoras in Fall 2020: Alkalinity Observations in a Degrading Permafrost Catchment

Abstract

The Arctic is highly susceptible to climate change. Compared to the global mean, the Arctic surface air temperature has increased more than double over the last two decades. Permafrost is particularly sensitive to rising air temperatures. In ice-rich permafrost, a change in the thermal regime can either lead to erosional events or cause surface subsidence due to a gradual deeper thawing. An enhanced permafrost degradation will alter the fluvial suspended sediment flux into the Arctic Ocean. Alkalinity – the ocean’s CO2 and pH buffer capacity – will also be affected, as riverine alkalinity is mainly produced from chemical weathering (dissolution) of minerals in watersheds including silicates as well as limestone and dolomite. The driver for the dissolution is the corrosive action of dissolved atmospheric or biologically respired CO2. Therefore, the changing Arctic will alter regional and global carbon budgets. With this field study, we will investigate the impact of an enhanced erosion from permafrost thaw on alkalinity in a small Arctic catchment. In particular, we will quantify a change in erosion within the catchment by comparing a pre-industrial with a current erosion rate and link this to riverine alkalinity levels.