Wetland expansion on the continental shelf of the northern South China Sea during deglacial sea level rise

QUATERNARY SCIENCE REVIEWS

卷:231

Article

Chen, Yunru¹  Huang, Enqing¹  Schefuss, Enno²  Mohtadi, Mahyar²  Steinke, Stephan^3,4  Liu, Jingjing¹  Martinez-Mendez, Gema⁵  Tian, Jun¹ 

[1] Tongji Univ, State Key Lab Marine Geol, 1239 Siping Rd, Shanghai 200092, Peoples R China

[2] Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany

[3] Xiamen Univ, Dept Geol Oceanog, Xiamen, Peoples R China

[4] Xiamen Univ, State Key Lab Marine Environm Sci, Xiamen, Peoples R China

[5] Helmholtz Ctr Polar & Marine Res, Alfred Wegener Inst, Alten Hafen 26, D-27568 Bremerhaven, Germany

关键词: Vegetation composition;    Plant-wax lipids;    Compound-specific carbon isotopes;    East Asian monsoon;    Coastal environments;   

DOI  :  10.1016/j.quascirev.2020.106202

来源: Elsevier

【 摘 要 】

To identify environmental causes for past changes in vegetation in subtropical East Asia, we present carbon isotope compositions of plant-wax n-alkanes and provide estimates of the C-4-plant contribution across the past four glacial terminations and interglacials, based on cores recovered from the northern South China Sea. Our results show a comparable C-4-plant contribution between the Last Glacial Maximum (LGM) and the Holocene. An increase of the C-4-plant contribution by 15-20% is found for Terminations IV, II and I relative to subsequent interglacial peaks, coeval with an expansion of Cyperaceae and Poaceae. In contrast, Termination V reveals a lower C-4-plant contribution than Marine Isotope Stage (MIS) 11c. The data exhibit a long-term trend, with a stepwise increase of the C-4-plant contribution across interglacials MIS 11c, 9e, 7e and 1. We suggest that no substantial changes in humidity levels over glacial-interglacial cycles occurred facilitating a similar C-3/C-4-plant ratio for the LGM and the Holocene. Instead, deglacial sea-level rises caused an extensive development of floodplains and wetlands on the exposed continental shelf, providing habitats for the spread of C-4 sedges and grasses. The progressive subsidence of Chinese coastal areas and the broadening of the continental shelf over the late Quaternary explains the nearly absence of C-4 plant occurrence during Termination V and a gradual increase of the C-4-plant contribution across interglacial peaks. Taken together, changes in coastal environments should be considered when interpreting marine-based vegetation reconstructions from subtropical Asia. (C) 2020 Elsevier Ltd. All rights reserved.

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