Pore-water analyses of permafrost deposits from Byk_98_MB-6.3 (Bykovsky Peninsula in 1998)@en

In order to get information about the pore-water characteristics from the dry samples, the water-soluble elements in the sediments were determined by shaking the samples with a proportionate amount of ultrapure water for a defined period of time. To obtain the water extracts, approximately 1 g of the freeze-dried sample was shaken for approximately 90 minutes in 50 ml centrifuge tubes with ultrapure water at a soil:water ratio of 1:25 using an overhead shaker (Gerhardt Laboshake). Then the suspension was centrifuged (Heraeus Multifuge 3s) at 4000 rpm for 15 minutes. The decanted extraction was filtered through a 0.45 µm cellulose acetate filter. We measured total dissolved elemental concentrations of Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, Si, and Sr and anion concentrations of F-, Cl-, SO42-, Br-, NO3-, PO43-, and HCO3-.The element concentrations were analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES, Perkin-Elmer Optima 8300DV), while the anion content was determined by ion chromatography (IC, Thermo ICS2100). Hydrogen carbonate concentrations were measured by potentiometric pH-value titration with 0.01 M HCl using an automatic titrator (Metrohm 794 Basic Titrino). In order to estimate the procedural error, extractions were carried out in duplicate for every 5th to 10th sample and 2-3 blank solutions of ultrapure water were treated in the same manner as the extractions and measured for concentrations. Water EC and pH values were measured using a WTW MultiLab 540 multi-parameter device equipped with a TetraCon 325 cell referenced to 25 °C and a pH Sentix 81 electrode.