Xiaowen Jia,b,c, Evgeny Abakumovb, Vyacheslav Polyakovb,d,e, Xianchuan Xiea*
aState Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210093, P. R. China
bDepartment of Applied Ecology, Saint Petersburg State University, Saint Petersburg, 199178, Russian Federation
c School of Environment and Sustainability, University of Saskatchewan, Saskatoon SK, S7N 5B3, Canada
d Arctic and Antarctic Research Institute, Saint Petersburg, 199397, Russian Federation
e Department of Soil Science and Agrochemistry, Saint-Petersburg State Agrarian University, Pushkin, Saint Petersburg, 19660, Russian Federation
* Corresponding author’s e-mail: xchxie@nju.edu.com
Text S1. The detailed description of pH values for supra-permafrost water in TA, SY, and MU for different sampling months.
For all periods, the supra-permafrost waters were very acidic with the pH values ranging from 4.06 to 4.93 for Ta, from 3.80 to 4.83 for Sy, and from 3.70 to 4.86 for Mu. In spring the pH values ranged from 4.06 to 4.20 (mean = 4.13) for Ta, from 3.80 to 3.89 (mean = 3.84) for Sy, from 3.70 to 3.96 (mean = 3.81) for Mu. During early June to end of August, the pH ranged from 4.2 to 4.57 (mean = 4.40) for Ta, from 3.81 to 4.57 (mean = 4.26) for Sy, and from 3.90 to 4.67 (mean = 4.33) for Mu. During autumn, the pH values ranged from 4.5 to 4.9 (mean = 4.77) for Ta, from 4.34 to 4.83 (mean = 4.62) for Sy, and from 4.15 to 4.86 (mean = 4.65) for Mu. The lowest concentrations for three sites were approximately at the beginning of May, and the highest concentrations for three sites were observed in October 12, 2016.
Text S2. The detailed description of pH values for the surface water surrounding the soil cores for different sampling months.
Ta exhibited acidity (pH = 6.31-6.85) from spring to the late summer in the streams and kept neutral during autumn seasons, except for two dates in late September. For the Taz river, the pH values ranged from 6.82 to 7.15, with the average value of 6.99 from spring to the beginning of summer and decreased beginning late July. From August, pH values showed an increasing trend until the beginning of October, when the pH values reached their peak (pH = 8.14). In Mu, the pH values of streams fluctuated from 6.11 (the beginning of May) to 6.43 (the end of August) and raised dramatically to between 6.91 and 7.15 from September to the middle of October. The Murtyyakha river showed a relatively higher pH value at the end of May (6.91) and middle of June (6.92), during early summertime and gradually increased from the end of summer to the late autumn with the peak value of 7.84. Sy revealed more acidic pH values (5.71-5.92) in the streams during May and kept stable pH values during June to July, while pH values increased significantly in August and gradually increased until October. The Syoyakha river also showed acidity before late autumn, except for two peaks where the pH values were close to 7 in May and June and the highest pH values were observed in the beginning of October (pH = 7.44).
Text S3. CO2, CH4 and DOC in the surrounding hydrological streams.
In SY, the average CO2 concentration increased from May (164 μmol L-1) to October (178 μmol L-1). CH4 average concentrations increased from 32 to 37 μmol L-1 from May to October and that of DOC increased from 164 to 178 mg L-1 from May to October. The same increasing trends were observed in MU and TA. During May to October, the average DOC, CO2 and CH4 concentrations for MU rose from 32 mg L-1, 162 μmol L-1 and 5 μmol L-1 to 38 mg L-1, 178 μmol L-1and 11μmol L-1 respectively, which for TA rose from 39 mg L-1, 202 μmol L-1 and 4 μmol L-1 to 61 mg L-1, 288 μmol L-1and 14 μmol L-1 respectively. The apparent increasing time for MU and SY was in August while for TA was in July.
Table S1. EDX results for soil core collected adjacent to Taz river (TA), Syoyakha river (SY), and Murtyyakha (MU) river in Yamal-Nets Autonomous Region. The values are in mg kg-1.