Abstract
In the hadal zone of the ocean (6–11 km), the characteristics of sinking marine snow particlesand their attached microbial communities remain elusive, despite their potential importancefor benthic life thriving at extreme pressures (60–110 MPa). Here, we used simulationexperiments to explore how increasing pressure levels modify the microbial degradation,organic matter composition, and microbiome of sinking diatom aggregates. Individualaggregates were incubated in rotating tanks in which pressure was incrementally increased tosimulate a descent from surface to hadal depth within 20 days. Incubations at atmosphericpressure served as controls. With increasing pressure, microbial respiration and diatomdegradation decreased gradually and ceased completely at 60 MPa. Dissolved organic carbonleaked substantially from the aggregates at ≥40 MPa, while diatom lipid and pigment contents decreased moderately. Bacterial abundance remained stable at >40 MPa, but bacterialcommunity composition changed significantly at 60–100 MPa. Thus, pressure exposurereduces microbial degradation and transforms both organic matter composition and microbiomes of sinking particles, which may seed hadal sediments with relatively fresh particulateorganic matter and putative pressure-tolerant microbes.
| Originalsprog | Engelsk |
|---|---|
| Artikelnummer | 377 |
| Tidsskrift | Communications Earth & Environment |
| Vol/bind | 4 |
| Udgave nummer | 1 |
| Antal sider | 14 |
| ISSN | 2662-4435 |
| DOI | |
| Status | Udgivet - dec. 2023 |
Bibliografisk note
Funding Information:We would like to thank Anni Glud, Birthe Christensen, Morten Alitouche Kieler, Feiyang Gu, Erik Laursen, Martina Alisch, Gaby Eickert-Groetzschel, Clemens Röttgen, Stephanie Caddell, Sherif Ghobrial, Leah Brinch Iversen, and Hans Frederik Hansen for technical assistance. We also thank Carol Arnosti for kindly providing the FLA-labelled polysaccharide substrates for the enzyme activity measurements. This study was financially supported by the Danish National Research Foundation through the Danish Center for Hadal Research (HADAL, Grant No. DNRF145) and the European Union’s Horizon 2020 Research and Innovation Program (HADES-ERC, Grant agreement No. 669947). Laboratory work by ME was supported by Deutsche Forschungsgemeinschaft through the Cluster of Excellence EXC 2077 “The Ocean Floor - Earth’s Uncharted Interface” (Project No. 390741601).
Funding Information:
We would like to thank Anni Glud, Birthe Christensen, Morten Alitouche Kieler, Feiyang Gu, Erik Laursen, Martina Alisch, Gaby Eickert-Groetzschel, Clemens Röttgen, Stephanie Caddell, Sherif Ghobrial, Leah Brinch Iversen, and Hans Frederik Hansen for technical assistance. We also thank Carol Arnosti for kindly providing the FLA-labelled polysaccharide substrates for the enzyme activity measurements. This study was financially supported by the Danish National Research Foundation through the Danish Center for Hadal Research (HADAL, Grant No. DNRF145) and the European Union’s Horizon 2020 Research and Innovation Program (HADES-ERC, Grant agreement No. 669947). Laboratory work by ME was supported by Deutsche Forschungsgemeinschaft through the Cluster of Excellence EXC 2077 “The Ocean Floor - Earth’s Uncharted Interface” (Project No. 390741601).