Effect of benzoate on microbial decomposition of fulvic acids in Tjeukemeer (the Netherlands)

Abstract

The addition of benzoic acid to water from Tjeukemeer stimulated bacterial growth and decreased both the fluorescence and the color of the water, indicating disappearance of fulvic acids. This stimulation of bacterial growth is shown to result most likely from a priming effect of benzoic acid on the slow microbial decomposition of fulvic acid. During growth of an Arthrobacter from the lake on benzoic acid in the presence of fulvic acid, fulvic acid of relatively small molecular size was formed from fulvic acid of relatively large molecular size, suggesting that microbial activity may play a role in the seasonal fluctuations in the molecular size distribution of fulvic acids in Tjeukemeer.