Loss of total sulfur and changes in sulfur isotopic ratios due to drying of lacustrine sediments

Abstract

Two independent methods for measuring total sulfur were used to show that underestimates of sulfur content of lacustrine sediments can occur when sediments are dried before total sulfur analysis. Different types of sediments were oven dried at 60° or 100°C or lyophilized to assess the effect of the drying method on the amount of sulfur lost. Losses ranged from 0 to 86%. Common losses were 6–22% and dependent on the sample and drying method used. Lyophilization caused greater sulfur losses (1.5‐fold) than the two oven‐drying methods. These sulfur losses caused changes in the sulfur isotopic content of the sediments and could underestimate rates of sulfur burial in sediments, organic‐S formation in sediments, and internal alkalinity production in lakes.