Organic Matter Sources in North Atlantic Fjord Sediments

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Faust, Johan Christoph, Knies, Jochen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2019
• Subjects: VDP::Mathematics and natural science: 400::Geosciences: 450; VDP::Matematikk og Naturvitenskap: 400::Geofag: 450; fjord; organic carbon; source to sink; land-ocean interaction; carbon accumulation; marine sediments; Greenland; Norway; Svalbard; Arctic; East Greenland; north atlantic current; North Atlantic; Northern Norway
• Online Access: https://hdl.handle.net/10037/15823; https://doi.org/10.1029/2019GC008382

Source at https://doi.org/10.1029/2019GC008382. ©2019. American Geophysical Union. All Rights Reserved. To better constrain the global carbon cycle fundamental knowledge of the role of carbon cycling on continental margins is crucial. Fjords are particularly important shelf areas for carbon burial due to relatively high sedimentation rates and high organic matter fluxes. As terrigenous organic matter is more resistant to remineralization than marine organic matter, a comprehensive knowledge of the carbon source is critical to better constrain the efficiency of organic carbon burial in fjord sediments. Here we investigated highly productive fjords in northern Norway and compare our results with both existing and new organic carbon to organic nitrogen ratios and carbon stable isotope compositions from fjords in mid‐Norway, west Svalbard, and east Greenland. The marine organic carbon contribution varies significantly between these fjords, and the contribution of marine organic carbon in Norwegian fjords is much larger than previously suggested for fjords in NW Europe and also globally. Additionally, northern Norwegian fjords show very high marine carbon burial rates (73.6 gC · m ‐2 · year ‐1 ) suggesting that these fjords are probably very distinct carbon burial hotspots. We argue that the North Atlantic Current inflow sustains these high burial rates and changes in the current strength due to ongoing climate change are likely to have a pronounced effect on carbon burial in North Atlantic fjords.