TY - JOUR

T1 - Utilization of low-molecular-weight organic compounds by the filterable fraction of a lotic microbiome

AU - Ghuneim, Lydia Ann

AU - Distaso, Marco

AU - Chernikova, Tatyana

AU - Bargiela, Rafael

AU - Lunev, Evgenii A.

AU - Korzhenkov, Aleksei A.

AU - Toshchakov, Stepan V.

AU - Rojo, David

AU - Barbas, Coral

AU - Ferrer, Manuel

AU - Golyshina, Olga

AU - Golyshin, Peter

AU - Jones, Davey L.

N1 - © The Author(s) 2020. Published by Oxford University Press on behalf of FEMS.

PY - 2021/2/1

Y1 - 2021/2/1

N2 - Filterable microorganisms participate in dissolved organic carbon (DOC) cycling in freshwater systems, however their exact functional role remains unknown. We determined the taxonomic identity and community dynamics of prokaryotic microbiomes in the 0.22 µm-filtered fraction and unfiltered freshwater from the Conwy River (North Wales, UK) in microcosms and, using targeted metabolomics and 14C-labelling, examined their role in the utilization of amino acids, organic acids and sugars spiked at environmentally-relevant (nanomolar) concentrations. To identify changes in community structure, we used 16S rRNA amplicon and shotgun sequencing. Unlike the unfiltered water samples where the consumption of DOC was rapid, the filtered fraction showed a 3-day lag phase before the consumption started. Analysis of functional categories of clusters of orthologous groups of proteins (COGs) showed that COGs associated with energy production increased in number in both fractions with substrate addition. The filtered fraction utilized low-molecular-weight (LMW) DOC at much slower rates than the whole community. Addition of nanomolar concentrations of LMW DOC did not measurably influence the composition of the microbial community nor the rate of consumption across all substrate types in either fraction. We conclude that due to their low activity, filterable microorganisms play a minor role in LMW DOC processing within a short residence time of lotic freshwater systems.

AB - Filterable microorganisms participate in dissolved organic carbon (DOC) cycling in freshwater systems, however their exact functional role remains unknown. We determined the taxonomic identity and community dynamics of prokaryotic microbiomes in the 0.22 µm-filtered fraction and unfiltered freshwater from the Conwy River (North Wales, UK) in microcosms and, using targeted metabolomics and 14C-labelling, examined their role in the utilization of amino acids, organic acids and sugars spiked at environmentally-relevant (nanomolar) concentrations. To identify changes in community structure, we used 16S rRNA amplicon and shotgun sequencing. Unlike the unfiltered water samples where the consumption of DOC was rapid, the filtered fraction showed a 3-day lag phase before the consumption started. Analysis of functional categories of clusters of orthologous groups of proteins (COGs) showed that COGs associated with energy production increased in number in both fractions with substrate addition. The filtered fraction utilized low-molecular-weight (LMW) DOC at much slower rates than the whole community. Addition of nanomolar concentrations of LMW DOC did not measurably influence the composition of the microbial community nor the rate of consumption across all substrate types in either fraction. We conclude that due to their low activity, filterable microorganisms play a minor role in LMW DOC processing within a short residence time of lotic freshwater systems.

U2 - 10.1093/femsec/fiaa244

DO - 10.1093/femsec/fiaa244

M3 - Article

C2 - 33264383

VL - 97

JO - Fems Microbiology Ecology

JF - Fems Microbiology Ecology

SN - 0168-6496

IS - 2

ER -