Competition and predation as possible causes of bacterial rarity

• Published in: Environmental microbiology Vol. 21; no. 4; pp. 1356 - 1368
• Main Authors: Kurm, Viola, van der Putten, Wim H., Weidner, Simone, Geisen, Stefan, Snoek, Basten L., Bakx, Tanja, Hol, Wilhelmina H. Gera
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2019; Wiley Subscription Services, Inc
• Subjects: Abundance; Availability; Bacteria; Bacteria - classification; Bacteria - drug effects; Bacterial Physiological Phenomena; Biointeractions and Plant Health; Biological competition; Communities; Competition; Competitiveness; Dispersal; Ecosystem; environmental factors; Eukaryota - metabolism; Groep Koornneef; Interspecific relationships; Laboratorium voor Nematologie; Laboratory of Nematology; Mineral nutrients; Nutrient availability; Nutrient concentrations; nutrient content; Nutrients - pharmacology; PE&RC; Population Density; PPO/PRI Biointeracties en plantgezondheid; PPO/PRI Biointeractions and Plant Health; Predation; Predators; Protists; Resource availability; Soil; Soil - parasitology; Soil bacteria; Soil Microbiology; Soil microorganisms
• ISSN: 1462-2912; 1462-2920; 1462-2920
• DOI: 10.1111/1462-2920.14569

Summary We assembled communities of bacteria and exposed them to different nutrient concentrations with or without predation by protists. Taxa that were rare in the field were less abundant at low nutrient concentrations than common taxa, independent of predation. However, some taxa that were rare in the field became highly abundant in the assembled communities, especially under ample nutrient availability. This high abundance points at a possible competitive advantage of some rare bacterial taxa under nutrient‐rich conditions. In contrast, the abundance of most rare bacterial taxa decreased at low resource availability. Since low resource availability will be the prevailing situation in most soils, our data suggests that under those conditions poor competitiveness for limiting resources may contribute to bacterial rarity. Interestingly, taxa that were rare in the field and most successful under predator‐free conditions in the lab also tended to be more reduced by predation than common taxa. This suggests that predation contributes to rarity of bacterial taxa in the field. We further discuss whether there may be a trade‐off between competitiveness and predation resistance. The substantial variability among taxa in their responses to competition and predation suggests that other factors, for example abiotic conditions and dispersal ability, also influence the local abundance of soil bacteria.