Quantifiying the Global Organic Carbon Budget in Marine Sediments

Marine sediments play a crucial role in the global carbon cycle, acting as the final sink of organic carbon (OC) and sequestering it for geological timescales, contributing to the drawdown of atmospheric CO₂. Despite the significance of quantifying the OC budget in marine sediments, there remains a lack of consensus on the magnitude of OC buried and its spatial distribution. The factors influencing this carbon sink involve a complex interplay between OC composition, depositional processes, and environmental conditions, with the relative importance of each mechanism still uncertain. Moreover, OC in marine sediments originates from both marine productivity and terrestrial organic matter transported via rivers. Understanding the spatial distribution and magnitude of these sources is essential for a comprehensive view of the role of marine sediments in the global carbon cycle. However, terrestrial OC includes biogenic OC, which contributes to current atmospheric CO₂ drawdown, and petrogenic OC from rock weathering, which does not. Thus, distinguishing these sources is crucial for accurate OC budget quantification. Leveraging large datasets and advanced spatial machine learning algorithms, we will quantify the OC budget, identify the factors affecting its magnitude and spatial distribution, and differentiate between marine, biogenic terrestrial, and petrogenic OC sources in global marine sediments.