Image1_Sedimentary Anthropogenic Carbon Signals From the Western Pacific Margin for the Last Century.pdf

• Main Authors: Jay Lee (2373886), Rick J. Yang (11616319), Hui-Ling Lin (4971808), Yi-Chi Chen (7884647), Ren-Yi Cai-Li (12014627), Haojia Ren (8964302), James T. Liu (11616322)
• Format: Still Image
• Language: unknown
• Published: 2022
• Subjects: Solid Earth Sciences; Climate Science; Atmospheric Sciences not elsewhere classified; Exploration Geochemistry; Inorganic Geochemistry; Isotope Geochemistry; Organic Geochemistry; Geochemistry not elsewhere classified; Igneous and Metamorphic Petrology; Ore Deposit Petrology; Palaeontology (incl. Palynology); Structural Geology; Tectonics; Volcanology; Geology not elsewhere classified; Seismology and Seismic Exploration; Glaciology; Hydrogeology; Natural Hazards; Quaternary Environments; Earth Sciences not elsewhere classified; Evolutionary Impacts of Climate Change; anthropogenic activity; corals; sediment cores; δ13C; δ18O; foraminifera; Pacific; Indian; Planktonic foraminifera
• Online Access: https://doi.org/10.3389/feart.2021.795519.s001

The declining trend of the δ 13 C of tropical corals over the last century was about −0.01‰ year −1 , according to global coral records. The decrease was attributable to the significant input of anthropogenic CO 2 ( 13 C Suess effect) to the atmosphere. Previous studies of δ 13 C in corals suggested that the signal of the anthropogenic carbon in the Pacific and Indian Oceans were weaker than that in the Atlantic Ocean. However, biases relating to environments in which corals grew caused concerns. To investigate the anthropogenic carbon signal in the Western Pacific, foraminiferal records in a suite of 13 box cores with good age control were obtained from the continental slope off southwestern Taiwan between 2004 and 2006. δ 18 O values of planktonic foraminifera (Globigerinoides sacculifer or so-called Trilobatus sacculifer) in collected cores were relatively stable at −2.5‰ to −2‰ in the last century, but foraminiferal δ 13 C had a gradual secular decline after the 1900s. The decline trend of δ 13 C began to intensify after the 1960s, and its rate was similar to that observed in the Atlantic. Similar decline trends of δ 13 C were also found in coral records at regions where the human activity is high (Liuqiu) and low (Dongsha). Our findings indicate that the anthropogenic carbon signal in the Western Pacific was not weaker than that recorded in the Atlantic, and the nearshore sediment can supplement the lack of δ 13 C records in corals, which are deficient when the environment is not suitable to grow.