Terrigenous dissolved organic matter persists in the energy-limited deep groundwaters of the Fennoscandian Shield.

ABSTRACT: The deep terrestrial biosphere encompasses the life below the photosynthesis-fueled surface that perseveres in typically nutrient and energy depleted anoxic groundwaters. The composition and cycling of this vast dissolved organic matter (DOM) reservoir relevant to the global carbon cycle remains to be deciphered. Here we show that recent Baltic Sea-influenced to ancient pre-Holocene saline Fennoscandian Shield deep bedrock fracture waters carried DOM with a strong terrigenous signature and varying contributions from abiotic and biotic processes. Removal of easily degraded carbon at the surface-to-groundwater transition and corresponding microbial community assembly processes likely resulted in the highly similar DOM signatures across the notably different water types that selected for a co

SUBMITTER: Osterholz H 

PROVIDER: S-EPMC9385861 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature