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Microscale sulfur cycling in the phototrophic pink berry consortia of the S ippewissett S alt M arsh
Author(s) -
Wilbanks Elizabeth G.,
Jaekel Ulrike,
Salman Verena,
Humphrey Parris T.,
Eisen Jonathan A.,
Facciotti Marc T.,
Buckley Daniel H.,
Zinder Stephen H.,
Druschel Gregory K.,
Fike David A.,
Orphan Victoria J.
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12388
Subject(s) - anoxygenic photosynthesis , sulfur , sulfide , sulfate , sulfate reducing bacteria , environmental chemistry , berry , biogeochemical cycle , sulfur cycle , biology , sulfur metabolism , microbial mat , phototroph , botany , bacteria , chemistry , photosynthesis , cyanobacteria , organic chemistry , genetics
Summary Microbial metabolism is the engine that drives global biogeochemical cycles, yet many key transformations are carried out by microbial consortia over short spatiotemporal scales that elude detection by traditional analytical approaches. We investigate syntrophic sulfur cycling in the ‘pink berry’ consortia of the S ippewissett S alt M arsh through an integrative study at the microbial scale. The pink berries are macroscopic, photosynthetic microbial aggregates composed primarily of two closely associated species: sulfide‐oxidizing purple sulfur bacteria ( PB ‐ PSB 1) and sulfate‐reducing bacteria ( PB ‐ SRB 1). Using metagenomic sequencing and 34 S ‐enriched sulfate stable isotope probing coupled with nanoSIMS , we demonstrate interspecies transfer of reduced sulfur metabolites from PB ‐ SRB 1 to PB ‐ PSB 1. The pink berries catalyse net sulfide oxidation and maintain internal sulfide concentrations of 0–500 μ m . Sulfide within the berries, captured on silver wires and analysed using secondary ion mass spectrometer, increased in abundance towards the berry interior, while δ 34 S‐ sulfide decreased from 6‰ to −31‰ from the exterior to interior of the berry. These values correspond to sulfate–sulfide isotopic fractionations (15–53‰) consistent with either sulfate reduction or a mixture of reductive and oxidative metabolisms. Together this combined metagenomic and high‐resolution isotopic analysis demonstrates active sulfur cycling at the microscale within well‐structured macroscopic consortia consisting of sulfide‐oxidizing anoxygenic phototrophs and sulfate‐reducing bacteria.