Time: 10:00-11:30, October 10 (Wednesday)
Venue: Lecture Hall 221, Institute of Surface-Earth System Science (Building No. 16), Tianjin University
Speaker: Rui Bao
Abstract: Understanding the origin and fate of organic carbon on continental shelves has been a long-standing issue that has garnered the attention of many geoscientists. Investigations on the carbon isotopic characteristics of organic matter in marine sediment provide important constraints on the functioning of the carbon cycle, with radiocarbon (14C) serving as a key tool for studying carbon cycle processes in contemporary oceans. The 14C age of organic matter accumulating in sediments on continental margins can shed light on processes that are involved in carbon cycling in the dynamic marine environments. However, it has proven challenging to constrain the role of hydrodynamic processes on observed 14C ages of bulk organic matter. Here, I launched a detailed 14C-based investigation on thermally-resolved organic carbon fractions and specific biomarkers across a spectrum of grain size fractions of continental shelf sediments. My results show that hydrodynamic processes are a key modulator of organic carbon dynamics during lateral transport of sedimentary organic matter, which functions as an “aging factory”. The aging of organic matter during across-shelf transport emerges as a widespread phenomenon, comprising an important facet of the marine carbon cycle. Moreover, my works reveal translocation and burial of the aged organic carbon into hadal environment, shedding new light on the nature and dynamics of organic carbon supply to deep ocean.
