Semi-enclosed bays serve as hotspots for black carbon burial: A case study in Jiaozhou Bay, western Yellow Sea

Utilization of Soot and 210 Po-210 Pb Disequilibria to Constrain Particulate Organic Carbon Fluxes in the Northeastern South China Sea

“…This process is proved by in situ seawater incubation experiments on DBC (Stubbins et al, 2012;Ward et al, 2014) and the decrease in DBC with depth in the euphotic zone (Fang et al, 2017). The other removal mechanism is the sinking of PBC, which has been reported in different marine environments, such as the Gulf of Maine (Flores-Cervantes et al, 2009), the western Arctic, and Subarctic Ocean (Fang et al, 2016), and Jiaozhou Bay (Feng et al, 2021). Yet, future research is needed to better understand the fate of BC in the ocean, especially regarding the quantification of the magnitude of the removal of BC from the water column.…”

“…This view is further supported by the small variations in the POC tot concentration, TSM concentration, and the soot to POC tot ratio (Figure 2). By contrast, the soot exhibited a rapid decrease from 75 to 200 m (Figure 2A), potentially due to quick removal via photochemical degradation and/or sinking (Stubbins et al, 2012;Feng et al, 2021). This layer, characterized by the steep temperature and salinity gradients as shown in Figure 1, largely prevented the vertical mixing of seawater with different soot concentrations.…”

The black carbon cycle and its role in the Earth system

“…After transport from rivers and other sources, PBC is thought to be primarily buried in coastal shelf and marine sediments and sequestered on long-term and potentially geologic timescales 100,101 . Semi-enclosed basins act as a trap for riverine PBC burial 102 , where PBC storage could be related to oxygen conditions 103 . However, burial and retention of PBC in marine sediments remains largely unconstrained on a global scale [104][105][106] .…”