Atmospheric Particles Are Major Sources of Aged Anthropogenic Organic Carbon in Marginal Seas

Abstract

Deposition of atmospheric particulates is a major pathway for transporting materials from land to the ocean, with important implications for climate and nutrient cycling in the ocean. Here, we report the results of year-round measurements of particulate organic carbon (POC) and black carbon (BC) in atmospheric aerosols collected on Tuoji Island in the coastal Bohai-Yellow Sea of China (2019–2020) and during a cruise in the western North Pacific. Aerosol POC contents ranged from 1.9 to 11.9%; isotope values ranged from −18.8 to −29.0‰ for δ13C and −150 to −892‰ for Δ14C, corresponding to 14C ages of 1,235 to 17,780 years before present (BP). Mass balance calculations indicated that fossil carbon contributed 19–66% of the POC, with highest values in winter. BC produced from fossil fuel combustion accounted for 18–54% of the POC. “Old” BC (mean 6,238 ± 740 yr BP) was the major contributor to POC, and the old ages of aerosol POC were consistent with the 14C ages of total OC preserved in surface sediments of the Bohai-Yellow Sea and East China Sea. We conclude that atmospheric deposition is an important source of aged OC sequestered in marginal sea sediments and thus represents an important sink for carbon dioxide from the atmosphere.

Distinct Radiocarbon Ages Reveal Two Black Carbon Pools Preserved in Large River Estuarine Sediments

“…Plot of (a) δ 13 C vs Δ 14 C values for solid-phase SBC and porewater DBC in the surface sediments of the Yangtze and Yellow River estuaries; the end-member values of different BC sources are shown. (b) Comparative plot of the carbon isotope values of BC in sediment, river, and atmospheric particles dissolved in river and estuarine sediment porewater (data are referenced from ,, ).…”

“…In our recent study, we collected atmospheric aerosol particles on Tuoji Island in the coastal Bohai-Yellow Sea of China for one year and found that 19–66% of the atmospheric POC comprised PBC with low Δ 14 C values (−544 ± 96‰, 7000 years), as 43% was produced from fossil fuel combustion. Thus, it can be concluded that atmospheric deposition is a significant source of aged anthropogenic OC in the marginal seas of China . After this PBC from rivers and the atmosphere is deposited into the estuarine and coastal sediments, the recently generated biomass-derived BC gradually degraded, dissolved into the porewater as DBC, and left the fossil material-derived BC, which was preserved in the solid phase as SBC; thus, the 14 C ages of the SBC became older than the PBC.…”

“…The Yangtze and Yellow Rivers are the two largest rivers in China, and their estuaries and adjacent shelf regions are highly dynamic due to large inputs of freshwater and terrestrial materials. The Yangtze and Yellow Rivers together deliver over 90% of the fresh water to the East China Sea and Bohai Sea. , Recent studies have shown that large amounts of BC are transported by the two rivers into coastal regions. ,, Our previous studies have demonstrated that the Yangtze River exports ∼192 Gg (1 Gg = 10 9 g) of particulate BC (PBC) to the East China Sea annually, and the Yellow River delivers ∼12 Gg of PBC to the Bohai Sea annually. , In addition, atmospheric deposition could contribute 55 ± 19 Gg aerosol PBC to the East China Sea and ∼88 Gg aerosol PBC to the Bohai Sea annually. , Large amounts of this river- and atmospherically transported PBC are deposited and buried in the sediments of the estuaries, making the two estuaries ideal regions for studying the transformation and cycling of BC in sediments.…”

Quantitative Analysis of the Cu Element Enhanced by AgNPs in a Single Microsized Suspended Particle Based on Optical Trapping-LIBS and Machine Learning

“…1 Particulate matter (PM), which coexists with various chemical and physical substances, is one of the atmospheric pollutants. 2 Owing to their large specific surface area and strong adsorption, atmospheric aerosol particles can absorb a large number of viruses, bacteria, nitrogen oxides, polycyclic aromatic hydrocarbons, and heavy metals in the atmosphere, 3,4 which can be inhaled into human alveoli and deposited during long-term exposure, posing health risks to humans. 5 Even though routine analytical techniques for particles have perfect detection sensitivity and accuracy, they are not conducive to the online and rapid analysis of metal elements in atmospheric aerosol particles, because these techniques involve expensive instruments and complex sample pretreat- ment and are labor-intensive.…”

“…Particulate matter (PM), which coexists with various chemical and physical substances, is one of the atmospheric pollutants . Owing to their large specific surface area and strong adsorption, atmospheric aerosol particles can absorb a large number of viruses, bacteria, nitrogen oxides, polycyclic aromatic hydrocarbons, and heavy metals in the atmosphere, , which can be inhaled into human alveoli and deposited during long-term exposure, posing health risks to humans …”