Methods:SamplingRhizon technique (Seeberg-Elverfeldt et al. 2005).SO42-Ion chromatography (Metrohm Compact IC 761 )Fe2+Measured using inductively coupled plasma-optical emission spectrometry (Iris Intrepid II ICP-OES).H2SSpectrophotometrically measured using methylene blue method (Cline, 1969).DICMeasured directly using a SEAL nutrient analyzer (based on Hall and Aller, 1992).Mn2+ Measured using inductively coupled plasma-optical emission spectrometry (Iris Intrepid II ICP-OES).CH4 Gac chromatography (Thermo Finnigan TRACE GC with FID, Oni et al. 2015a).