Exploratory radioisotope measurements suggest that in-stream erosion represents the main sediment source in a pristine, tropical rainforest in Costa Rica

Abstract

Paper summary generated by OpenAI: This study investigates sediment sources and erosion dynamics in a pristine tropical rainforest catchment in northern Costa Rica using exploratory radioisotope measurements, including U-235, Bi-214, Pb-214, total Pb-210, K-40, and the fallout radionuclide Cs-137. The findings reveal that in-stream erosion is the primary source of sediment, contributing approximately 79% to stream sediment, while superficial hillslope soils account for only 22%. Modeled erosion and accumulation rates on hillslopes ranged from 6 to 6.7 tons per hectare per year, highlighting the significant role of channel erosion processes in sediment yield despite the strong hydrological connection between hillslopes and streams. This research enhances the understanding of sediment dynamics in volcanic tropical landscapes, which are influenced by frequent geomorphic transformations.