In order to trace the transport of soil organic carbon (OC) in the lower Amazon basin, we investigated the distributions of crenarchaeol and branched glycerol dialkyl glycerol tetraethers (GDGTs) by analyzing riverbed sediments and river suspended particulate matter (SPM) collected in the Solimões-Amazon River mainstem and its tributaries. The Branched and Isoprenoid Tetraether (BIT) index, a proxy for river-transported soil OC into the ocean, was determined from the distributions of these GDGTs. The GDGT-derived parameters were compared with other bulk geochemical data (i.e. C:N ratio and stable carbon isotopic composition). The GDGT-derived and bulk geochemical data indicate that riverine SPM and riverbed sediments in the lower Amazon River and its tributaries are a mixture of C3 plant-derived soil OC and aquatic-derived OC. The branched GDGTs in the SPM and riverbed sediments did not predominantly originate from the high Andes soils (>2500 m in altitude) as was suggested previously. However, further ... : Supplement to: Kim, Jung-Hyun; Zell, Claudia; Moreira-Turcq, Patricia; Pérez, Marcela A P; Abril, Gwenaël; Mortillaro, Jean-Michel; Weijers, Johan W H; Meziane, Tarik; Sinninghe Damsté, Jaap S (2012): Tracing soil organic carbon in the lower Amazon River and its tributaries using GDGT distributions and bulk organic matter properties. Geochimica et Cosmochimica Acta, 90, 163-180 ...