Microbial functional genes elucidate environmental drivers of biofilm metabolism in glacier-fed streams


Ren, Z., Gao, H., Elser, J. J., & Zhao, Q. (2017). Microbial functional genes elucidate environmental drivers of biofilm metabolism in glacier-fed streams.  Scientific reports,  7(1), 12668.



Benthic biofilms in glacier-fed streams harbor diverse microorganisms driving biogeochemical cycles and, consequently, influencing ecosystem-level processes. Benthic biofilms are vulnerable to glacial retreat induced by climate change. To investigate microbial functions of benthic biofilms in glacier-fed streams, we predicted metagenomes from 16s rRNA gene sequence data using PICRUSt and identified functional genes associated with nitrogen and sulfur metabolisms based on KEGG database and explored the relationships between metabolic pathways and abiotic factors in glacier-fed streams in the Tianshan Mountains in Central Asia. Results showed that the distribution of functional genes was mainly associated with glacier area proportion, glacier source proportion, total nitrogen, dissolved organic carbon, and pH. For nitrogen metabolism, the relative abundance of functional genes associated with dissimilatory pathways was higher than those for assimilatory pathways. The relative abundance of functional genes associated with assimilatory sulfate reduction was higher than those involved with the sulfur oxidation system and dissimilatory sulfate reduction. Hydrological factors had more significant correlations with nitrogen metabolism than physicochemical factors and anammox was the most sensitive nitrogen cycling pathway responding to variation of the abiotic environment in these glacial-fed streams. In contrast, sulfur metabolism pathways were not sensitive to variations of abiotic factors in these systems.


I chose this article because I am very interested in biogeochemical cycling within stream biofilms, and how the diversity of microorganisms present can influence ecosystem processes. Adding glaciers to the mix just makes it more exciting! This article also uses methods we have learned about in class  (16srRNA gene sequencing), so the paper helped me better understand how these methods can be used in another environmental application.


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