Functional and genomic potential of microbial communities in TNT-contaminated sediments at a historical submarine wreck

Unexploded ordnance from World Wars I and II continues to release 2,4,6-trinitrotoluene into marine sediments, yet microbial responses to this chronic contamination remain poorly understood. Here, we characterize the taxonomic and functional potential of sediment microbiomes at the historical submarine wreck UC-30 in the North Sea, combining 16S rRNA amplicon sequencing, shotgun metagenomics, and targeted GC-MS/MS analysis with a parallel aerobic laboratory enrichment. Minewell sediments showed distinct community shifts, with enrichment of Proteobacteria, notably Haliaceae and Rhodobacteraceae, alongside increased representation of oxidoreductases and stress-related enzyme classes, including glutathione S-transferases. Genes associated with TNT transformation, including Old Yellow Enzymes and nitroreductases, were modestly enriched in situ. The laboratory enrichment confirmed TNT removal and presence of N-ethylmaleimide reductase, an Old Yellow Enzyme implicated in TNT transformation. Functional and taxonomic parallels between field and enrichment communities indicate shared adaptive capacities under TNT exposure, positioning contaminated marine microbiomes as reservoirs of bioremediation potential. Long-term TNT exposure at historical shipwrecks can influence sediment microbial communities, according to combined wreck sampling from the North Sea and laboratory incubation tests.