The record of sedimentary spheroidal carbonaceous particles (SCPs) in Beppu Bay, southern Japan, compared to historical trends of industrial activity and atmospheric pollution: Further evidence for SCPs as a marker for Anthropocene industrialization

Abstract

Spheroidal carbonaceous particles (SCPs) are carbonaceous fly ash particles produced solely from industrial fossil fuel combustion. SCPs in sediments can be an indicator of past industrialization. We examined the sedimentary SCP record in Beppu Bay, southern Japan, and compared this record to historical trends of industrial activity and monitoring data for atmospheric pollutions in the region. Beppu Bay has varved sediments in the absence of bioturbation, providing an ideal situation for SCP study. Our results show that the temporal variation of SCP deposition is consistent with the trends of industrial activity and the temporal variation of status of atmospheric pollution. We conclude that undisturbed sediments such as Beppu Bay sediments have SCP records that adequately represent historical trends of industrial activity and atmospheric pollution in detail. These findings support that SCPs are a potential marker for the Anthropocene, characterized by industrialization.

Beppu Bay, Japan, as a candidate Global boundary Stratotype Section and Point for the Anthropocene series

“…0aU3, started increasing at 64.5 cm rd (below Ev. 0aU2; 1949.5 CE), and rose abruptly at 49.5 cm rd between events 0aU1 and -1a (Inoue et al, 2022) (Figure 10).…”

“…For descriptions of figure details, see the caption for Figure 6. Data from Inoue et al (2022). Orange circle in the window denotes the same as a black circle in the corresponding year, but enlarged in the vertical scale.…”

“…Further, the depth profile of plutonium radio isotopes could serve as a reliable primary marker of the base of the proposed Anthropocene (Yokoyama et al, 2022). Analyses of sediments also record the timing of an initial inclusion of novel materials, such as spheroidal carbonaceous particles (SCPs, aka “fly ash”) (Inoue et al, 2022), polychlorinated biphenyls (PCBs, Takahashi et al, 2020), dichloro-diphenyl-trichloroethane (DDT) (Nishimuta et al, 2021) and brominated flame retardants (BFRs) (Hoang et al, 2021) after the mid 20th century. Each record reflects rapid industrialization of Japan during the Great Acceleration (Steffen et al, 2015), an array of global and near-synchronous signals ~1950 CE, including abrupt changes of socio-economic factors, biophysical processes and consequent environmental and climatic change (see the details in the introductory article to the special issue: Waters et al, 2023).…”

Part 2: Descriptions of the proposed Crawford Lake GSSP and supporting SABSs. The Anthropocene Epoch and Crawfordian Age: proposals by the Anthropocene Working Group

“…Constant and low SCP concentrations occur below 70.5 cm depth (before 1929 CE; Figure BB4h) (Inoue et al, 2022;. A slight SCP increase occurs above 69.5 cm depth (after 1932 CE) with a minor abrupt increase above 64.5 cm depth (after 1946 CE).…”

Part 1: Anthropocene Series/Epoch: stratigraphic context and justification of rank The Anthropocene Epoch and Crawfordian Age: proposals by the Anthropocene Working Group

“…The lake successions show a marked SCP upturn around the 1950s, providing a consistent marker globally, including during the study of the potential GSSP/SABSs/reference sections(McCarthy et al, 2023;Stegner et al, 2023; see Part 2). In addition, SCPs were shown to be promising markers in the Beppu Bay and East Gotland anoxic marine basins(Inoue et al, 2022;Kaiser et al, 2023), the Śnieżka Peatland (Fiałkiewicz-Kozieł et al, 2023) and were for the first time recorded in Antarctic ice(Thomas et al, 2023a, b) they are present in the Vienna anthropogenic deposits from the late 19 th century, with elevated levels from 1945 to post-1959 CE (N.L. Rose, pers.…”