Work

Exploring microbial diversity using cell-size fractionated enrichment incubations from subsurface aquifers at Äspö, Sweden

Year: 2026

Type: article

Abstract: The continental subsurface hosts energy-constrained groundwaters with a high diversity of ecologically elusive microorganisms adapted to the prevailing low-energy conditions. This study explored potential interactions among microbes using anaerobic enrichment incubations with three types of groundwater of contrasting hydrochemistry from the Äspö Hard Rock Laboratory, Sweden. Removing cells larger than 0.45 µm from the inoculum resulted in incubations enriched in populations characterized by very small genomes, including Patescibacteria, Nanobdellota, and Omnitrophota. These incubations had a higher diversity than non-fractionated incubations. However, cell numbers and community structure of the fractionated incubations did not change over an incubation period up to four months, despite high microbial diversity and experimental amendments with either simple (acetate) or more complex (cell lysate) carbon sources. In addition, network analysis on the groundwaters revealed multiple co-occurrences between populations affiliated with the Patescibacteria and the Desulfobacterota. Overall, these findings support that a considerable part of microbial diversity has a small cell size in these low energy groundwaters and strong co-occurrences among populations as an important survival strategy.

Source: Communications Biology

DOI: 10.1038/s42003-026-09706-8

Authors: George Westmeijer, Stephanie Turner, Patrik Hevele, Maliheh Mehrshad, Stefan Bertilsson, Mark Dopson

Institutions: Linnaeus University, Umeå University, Science for Life Laboratory, Swedish University of Agricultural Sciences

Language: English

Topic: Microbial Community Ecology and Physiology

Subfield: Ecology

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: gold

Estimated APC paid: $4,190