Microbial biomarkers support organic carbon transport from methane-rich Amazon wetlands to the shelf and deep sea fan during recent and glacial climate conditions

We observe comparable and unexpectedly invariant BHP composition in both marine sediment records, with a remarkably high relative abundance of C-35 amino BHPs including compounds specific for aerobic methane oxidation on the shelf (avg. 50% of all BHPs) and the fan (avg. 40%). Notably, these marine BHP signatures are strikingly similar to those of a methane-producing floodplain area in one of the Amazonian wetland (várzea) regions. The observation indicates that BHPs in the marine sediments may have initially been produced within wetland regions of the Amazon basin and may therefore document persistent export from terrestrial wetland regions, with subsequent re-working in the marine environment, both during recent and past glacial climate conditions.