Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1128/spectrum.00437-22
Licence creative commons licence
Title (Primary) Bacterial necromass is rapidly metabolized by heterotrophic bacteria and supports multiple trophic levels of the groundwater microbiome
Author Geesink, P.; Taubert, M.; Jehmlich, N. ORCID logo ; von Bergen, M.; Küsel, K.
Journal Microbiology Spectrum
Year 2022
Department MOLSYB
Volume 10
Issue 4
Page From e00437
Language englisch
Topic T9 Healthy Planet
Keywords groundwater, necromass, surface input, stable isotope probing, metaproteomics, subsurface, AquaDiva, groundwater
Abstract Pristine groundwater is a highly stable environment with microbes adapted to dark, oligotrophic conditions. Input events like heavy rainfalls can introduce the excess particulate organic matter, including surface-derived microorganisms, thereby disturbing the groundwater microbiome. Some surface-derived bacteria will not survive this translocation, leading to an input of necromass to the groundwater. Here, we investigated the effects of necromass addition to the microbial community in fractured bedrock groundwater, using groundwater mesocosms as model systems. We followed the uptake of 13C-labeled necromass by the bacterial and eukaryotic groundwater community quantitatively and over time using a complementary protein-stable and DNA-stable isotope probing approach. Necromass was rapidly depleted in the mesocosms within 4 days, accompanied by a strong decrease in Shannon diversity and a 10-fold increase in bacterial 16S rRNA gene copy numbers. Species of Flavobacterium, Massilia, Rheinheimera, Rhodoferax, and Undibacterium dominated the microbial community within 2 days and were identified as key players in necromass degradation, based on a 13C incorporation of >90% in their peptides. Their proteomes comprised various proteins for uptake and transport functions and amino acid metabolization. After 4 and 8 days, the autotrophic and mixotrophic taxa Nitrosomonas, Limnohabitans, Paucibacter, and Acidovorax increased in abundance with a 13C incorporation between 0.5% and 23%. Likewise, eukaryotes assimilated necromass-derived carbon either directly or indirectly. Our data point toward a fast and exclusive uptake of labeled necromass by a few specialists followed by a concerted action of groundwater microorganisms, including autotrophs presumably fueled by released, reduced nitrogen and sulfur compounds generated during necromass degradation.
Persistent UFZ Identifier
Geesink, P., Taubert, M., Jehmlich, N., von Bergen, M., Küsel, K. (2022):
Bacterial necromass is rapidly metabolized by heterotrophic bacteria and supports multiple trophic levels of the groundwater microbiome
Microbiol. Spectr. 10 (4), e00437