TY  - JOUR
A1  - Repasch, Marisa
A1  - Scheingross, Joel S.
A1  - Hovius, Niels
A1  - Vieth-Hillebrand, Andrea
A1  - Mueller, Carsten W.
A1  - Höschen, Carmen
A1  - Szupiany, Ricardo N.
A1  - Sachse, Dirk
T1  - River organic carbon fluxes modulated by hydrodynamic sorting of particulate organic matter
T2  - Geophysical research letters
N2  - Rivers regulate the global carbon cycle by transferring particulate organic carbon (POC) from terrestrial landscapes to marine sedimentary basins, but the processes controlling the amount and composition of fluvially exported POC are poorly understood. We propose that hydrodynamic sorting processes modify POC fluxes during fluvial transit. We test this hypothesis by studying POC transported along a similar to 1,200 km reach of the Rio Bermejo, Argentina. Nanoscale secondary ion mass spectrometry revealed that POC was either fine, mineral-associated organic matter, or coarse discrete organic particles. Mineral-associated POC is more resistant to oxidation and has a lower particle settling velocity than discrete POC. Consequently, hydraulic sorting and downstream fining amplify the proportion of fine, mineral-associated POC from similar to 55% to similar to 78% over 1,220 km of downstream transit. This suggests that mineral-associated POC has a greater probability of export and preservation in marine basins than plant detritus, which may be oxidized to CO2 during transit.
KW  - compound-specific stable isotopes
KW  - carbon fluxes
KW  - rivers
KW  - NanoSIMS;
KW  - sediment transport
KW  - hydrodynamic sorting
Y1  - 2022
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/64572
SN  - 0094-8276
SN  - 1944-8007
VL  - 49
IS  - 3
PB  - American Geophysical Union
CY  - Washington
ER  -