Mobilization of geochemical elements in the active layer of permafrost
to surface water in Russian Arctic
Abstract
The predicted increasing ground temperatures in the Arctic results in
the deepening of the active layer and intensification of geochemical
processes, which could affect the geochemical composition of surface
waters. Determining the responses of the riparian soil systems to
surrounding hydrological flows under changing climate conditions is
important for understanding the seasonal changes in hydrological
processes. Therefore, in this study, one soil core from the study area
polygon rim (close to the Taz River, TA) and two soil cores from the
riverain terrace (close to the Syoyakha River, SY and Murtyyakha River,
MU) in Russian Western Siberia and their supra-permafrost water,
adjacent stream flows and river water were sampled for analysis of
geochemical elements. The results showed that most elements above their
respective detection limits (Mn, Sr, Fe, Mg, Cr, Co, V, Pb, Al and Ca)
started to accumulate in the downwards gleyed layer during
September–October in response to the deepest thaw in the active layer.
This study focused on the highly mobile elements, i.e., Mn, Ca, Mg, Al
and Ti, in the deepest layer; and found the transport of organic matter
in the upper layer carried these elements to both surface water
ponds/flows and supra-permafrost water, and further, to the rivers. The
best linear correlation for both stream flows and river water were Mn,
which may be a proxy for predicting the processes occurring within the
active layer during the annual summer-autumn thaw. Finally, landscapes
with different ice contents may experience changes in the elements
transported to surface waters.