Testing the light:nutrient hypothesis: Insights into biofilm structure and function using metatranscriptomics

Veach, Allison M.; Griffiths, Natalie A.

doi:10.1111/mec.14733

Title: Testing the light:nutrient hypothesis: Insights into biofilm structure and function using metatranscriptomics

Journal Article · 12 July 2018 · Molecular Ecology

DOI: https://doi.org/10.1111/mec.14733 · OSTI ID:1460202

Veach, Allison M. ^[1]; Griffiths, Natalie A. ^[2]

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. and Environmental Sciences Division

Abstract Aquatic biofilms are hotspots of biogeochemical activity due to concentrated microbial biomass (Battin, Kaplan, Newbold, & Hansen, ). However, biofilms are often considered a single entity when their role in biogeochemical transformations is assessed, even though these biofilms harbour functionally diverse microbial communities (Battin, Besemer, Bengtsson, Romani, & Packmann, ; Veach, Stegen, Brown, Dodds, & Jumpponen, ). Often overlooked are the biotic interactions among biofilm components that can affect ecosystem‐scale processes such as primary production and nutrient cycling. These interactions are likely to be especially important under resource limitation. Light is a primary resource mediating algal photosynthesis and both phototrophic and heterotrophic production due to bacterial reliance on C‐rich algal exudates (Cole, ). However, current understanding of function–structure linkages in streams has yet to unravel the relative degree of these microbial feedbacks under resource availability gradients. In this issue of Molecular Ecology, Bengtsson, Wagner, Schwab, Urich, and Battin ( ) studied stream biofilm responses to light availability to understand its impact across three domains of life. By integrating biogeochemical rate estimation and metatranscriptomics within a microcosm experiment, they were able to link primary production and nutrient uptake rates to algal and bacterial metabolic processes and specify what taxa contributed to gene expression. Under low light, diatoms and cyanobacteria upregulated photosynthetic machinery and diatom‐specific chloroplast rRNA suggesting heightened transcriptional activity under light limitation to maintain phototrophic energy demands. Under high light, heterotrophic bacteria upregulated mRNA s related to phosphorous (P) metabolism while biofilm P uptake increased indicating high bacterial‐specific P demand when algal biomass was high. Together, these results indicate that biogeochemical function is mediated by complex microbial interactions across trophic levels.

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Research Organization:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE

Grant/Contract Number:: AC05-00OR22725; DE‐AC05‐00OR22725

OSTI ID:: 1460202

Alternate ID(s):: OSTI ID: 1464552

Journal Information:: Molecular Ecology, Vol. 27, Issue 14; ISSN 0962-1083

Publisher:: WileyCopyright Statement

Country of Publication:: United States

Language:: English

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