Microbial Dimethylsulfoniopropionate Cycling in Deep Sediment of the Mariana Trench

Abstract

Dimethylsulfoniopropionate (DMSP) is an abundant organosulfur molecule in the ocean and is the precursor for the climate-active volatile gas dimethyl sulfide. Previous studies focused mainly on bacterial DMSP cycling in seawater, coastal sediment, and surface trench sediment samples, but DMSP metabolism in the Mariana Trench (MT) subseafloor sediments remains unknown.

A unique subseafloor microbiosphere in the Mariana Trench driven by episodic sedimentation

“…A 752 cm long sediment core was collected by the research vessel Dongfanghong 3 in July 2020 from the Challenger Deep in the Mariana Trench (MT20-750, 11° 19.904ʹ N, 142° 12.083ʹ E) using a gravity corer (Cheng et al 2023 ) (Fig. 1 ).…”

“…Metagenomic DNA was extracted from 10 to 12 g of sediment samples for each experimental replicate as previously described (Cheng et al 2023 ; Zhou et al 1996 ). Briefly, biomass from 1 g samples was washed using 3.3 mL extraction buffer (100 mmol/L Tris–HCl [pH 8.0], 100 mmol/L sodium EDTA [pH 8.0], 100 mmol/L sodium phosphate [pH 8.0], 1.5 mol/L NaCl, 1% CTAB) and then centrifuged at 6000×g for 20 min at room temperature.…”

“…Metagenomic assembly, mapping, and binning were performed according to Xue et al ( 2020 ) with modifications. Briefly, raw sequence data with > 10% undefined bases, > 40% low-quality bases and > 15 bases matching the adapters were removed with the metaWRAP-Read_qc module (Cheng et al 2023 ; Uritskiy et al 2018 ). The clean reads ranging from 17.16 to 21.88 Gb per sample were then assembled with metaSPAdes version v3.15.2 (Nurk et al 2017 ).…”

“…The 16S amplicon datasets generated during the current study are available in the National Omics Data Encyclopedia under the accession number PRJCA008837. The metagenome data are from our recent work (Cheng et al 2023 ) and deposited in the NCBI database under the accession number PRJNA957232.…”