Endospores of thermophilic bacteria as tracers of microbial dispersal by ocean currents

• Published in: The ISME Journal Vol. 8; no. 6; pp. 1153 - 1165
• Main Authors: Müller, Albert Leopold, de Rezende, Júlia Rosa, Hubert, Casey R J, Kjeldsen, Kasper Urup, Lagkouvardos, Ilias, Berry, David, Jørgensen, Bo Barker, Loy, Alexander
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2014; Oxford University Press; Nature Publishing Group
• Subjects: 631/158/852; 631/326/2565/855; 631/326/41/2535; Arctic Regions; Arctic zone; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Biogeography; Biomedical and Life Sciences; Dispersal; Distribution patterns; Ecology; Evolutionary Biology; Firmicutes; Geologic Sediments - microbiology; Life Sciences; Marine microorganisms; Marine sediments; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microorganisms; Ocean circulation; Ocean currents; Ocean floor; Oceans; Oceans and Seas; Original; original-article; Phylogeny; Phylogeography; RNA, Ribosomal, 16S - genetics; Seawater - microbiology; Sedimentation; Spatial distribution; Spores, Bacterial - genetics; Temperature; Tracers; Water circulation; Water Movements; ANE, Baltic Sea; ANW, Atlantic, Baffin Bay; PN, Arctic; ISE, Mexico, California Gulf; PNE, Norway, Svalbard; ocean currents; endospores; thermophiles; marine microorganisms; biogeography
• ISSN: 1751-7362; 1751-7370; 1751-7370
• DOI: 10.1038/ismej.2013.225

Microbial biogeography is influenced by the combined effects of passive dispersal and environmental selection, but the contribution of either factor can be difficult to discern. As thermophilic bacteria cannot grow in the cold seabed, their inactive spores are not subject to environmental selection. We therefore conducted a global experimental survey using thermophilic endospores that are passively deposited by sedimentation to the cold seafloor as tracers to study the effect of dispersal by ocean currents on the biogeography of marine microorganisms. Our analysis of 81 different marine sediments from around the world identified 146 species-level 16S rRNA phylotypes of endospore-forming, thermophilic Firmicutes . Phylotypes showed various patterns of spatial distribution in the world oceans and were dispersal-limited to different degrees. Co-occurrence of several phylotypes in locations separated by great distances (west of Svalbard, the Baltic Sea and the Gulf of California) demonstrated a widespread but not ubiquitous distribution. In contrast, Arctic regions with water masses that are relatively isolated from global ocean circulation (Baffin Bay and east of Svalbard) were characterized by low phylotype richness and different compositions of phylotypes. The observed distribution pattern of thermophilic endospores in marine sediments suggests that the impact of passive dispersal on marine microbial biogeography is controlled by the connectivity of local water masses to ocean circulation.