Millennial scale persistence of organic carbon bound to iron in Arctic marine sediments
Burial of organic material in marine sediments represents a dominant natural mechanism of long-term carbon sequestration globally, but critical aspects of this carbon sink remain unresolved. Investigation of surface sediments led to the proposition that on average 10-20% of sedimentary organic carbo...
| Published in: | Nature Communications |
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| Main Authors: | , , , , , , , |
| Format: | Text |
| Language: | English |
| Published: |
Springer Science and Business Media LLC
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| Subjects: | |
| Online Access: | https://doi.org/10.1038/s41467-020-20550-0 https://archimer.ifremer.fr/doc/00675/78755/80923.pdf https://archimer.ifremer.fr/doc/00675/78755/80924.pdf https://archimer.ifremer.fr/doc/00675/78755/80925.pdf https://archimer.ifremer.fr/doc/00675/78755/80926.pdf https://archimer.ifremer.fr/doc/00675/78755/80927.xlsx |
| Summary: | Burial of organic material in marine sediments represents a dominant natural mechanism of long-term carbon sequestration globally, but critical aspects of this carbon sink remain unresolved. Investigation of surface sediments led to the proposition that on average 10-20% of sedimentary organic carbon is stabilised and physically protected against microbial degradation through binding to reactive metal (e.g. iron and manganese) oxides. Here we examine the long-term efficiency of this rusty carbon sink by analysing the chemical composition of sediments and pore waters from four locations in the Barents Sea. Our findings show that the carbon-iron coupling persists below the uppermost, oxygenated sediment layer over thousands of years. We further propose that authigenic coprecipitation is not the dominant factor of the carbon-iron bounding in these Arctic shelf sediments and that a substantial fraction of the organic carbon is already bound to reactive iron prior deposition on the seafloor. |
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