AUTHOR=Hall Edward , Besemer Katharina , Kohl Lukas , Preiler Christian , Riedel Katharina , Schneider Thomas , Wanek Wolfgang , Battin Tom 

TITLE=Effects of Resource Chemistry on the Composition and Function of Stream Hyporheic Biofilms

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 3 - 2012

YEAR=2012

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2012.00035

DOI=10.3389/fmicb.2012.00035

ISSN=1664-302X

ABSTRACT=Stream ecosystems process large quantities of dissolved organic matter as it moves from the headwaters to the sea. Interstitial sediments in the hyporheic zone are centers of high biogeochemical reactivity due to their high levels of microbial biomass and activity. However, the interaction between organic matter and microbial dynamics of these systems remains poorly understood. We evaluated how variance in resource chemistry affected the microbial community and its associated activity in experimentally grown interstitial biofilms. Specifically, we fed beech leaf leachates that differed in chemical composition to a series of bioreactors filled with sediment from a sub-alpine stream. Differences in resource chemistry resulted in differences in diversity and phylogenetic origin of microbial proteins, enzyme activity, and microbial biomass stoichiometry. Specifically, increased lignin, phenolics and manganese in a single leachate resulted in increased phenoloxidase and peroxidase activity, elevated microbial biomass carbon:nitrogen ratio, and a greater proportion of proteins of beta-proteobacter origin. We use this model system to link microbial form, (community composition and proteome), with function, (enzyme activity), in an attempt to develop a better understanding of the mechanisms that link resource heterogeneity to ecosystem function in stream ecosystems.