Variability of snail growing season at the Chinese Loess Plateau during the last 75 ka

• Published in: Chinese science bulletin Vol. 57; no. 9; pp. 1036 - 1045
• Main Authors: Huang, LinPei, Wu, NaiQin, Gu, ZhaoYan, Chen, XiaoYun
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer-Verlag 01.03.2012; SP Science China Press
• Subjects: Chemistry/Food Science; China; climate change; climatic zones; Earth Sciences; Engineering; growing season; Humanities and Social Sciences; Life Sciences; multidisciplinary; Physics; Science; Science (multidisciplinary); seasonal variation; snails; stable isotopes; 中国黄土高原; 全新世中期; 变异; 季节性; 末次盛冰期; 生长季节; 稳定同位素; 蜗牛; China; land snail; stable carbon and oxygen isotopes; last glacial; snail growing season; Xifeng loess sequence
• ISSN: 1001-6538; 1861-9541
• DOI: 10.1007/s11434-011-4931-z

Knowledge of seasonal climate change is one of the key issues facing Quaternary paleoclimatic studies and estimating seasonal climate change is difficult, especially changes such as seasonal length on glacial-interglacial timescales. The stable isotope com- position from seasonal land snail shells provides the potential to reveal seasonal climatic features. Two modern land snail species, cold-aridiphilous Pupilla aeoli and thermo-humidiphilous Punctum orphana, were collected from different climatic zones in 18 localities across the Chinese Loess Plateau, spanning 11 degrees of longitude and covering a range of 1000 km2. The duration of the snail growing season （temperature ≥10℃） was shorter （202 ± 6 d） in the eastern Loess Plateau compared with in the western Loess Plateau （162 ±7 d）. The δ13C of P. aeoli shells was -9.1‰ to -4.7‰ and -5.0‰ to 0.3‰ for δ18O. For P. orphana, the δl3C ranged from -9.1‰ to -1.9‰ and -8.9‰ to -2.9‰ for δ18O. Both the δ13C and δ18O differences between the two snail species were reduced from the east to the western Loess Plateau （2.8%0 to 0.2± 1.1‰ for δ13C and 4.7%0 to 2.9± 1.3‰ for δ18O）. These isotopic differences roughly reflect the difference in the growing season lengths between the east and west Loess Plateau indicat- ing that the duration of the snail growing season shortens by 15 d or 19 d if the difference decreases by 1%o in δ13C or δ18O, re- spectively. Thus, the difference in δ13C and δ18O between both snail species can be used to reveal the length of the snail growing season in the past. Based on our investigation, the length of the snail growing seasons from the Xifeng region during the last 75 ka was reconstructed. During the mid-Holocene （8-3 ka）, the mean isotopic difference from both snail species reached maximum values of 2.6 ± 0.7‰ and 2.1 ±1.4‰ for δ13C and δ18O, respectively. This was followed by MIS 3 that ranged from 2.5 ±0.4‰ for δ13C and 1.6 ± 0.8%0 for δ18O. The Last Glacial Maximum changed by only 0.2‰ and 0.4‰ for δ13C and δ18O, respectively. Therefore, we estimate that the duration of the snail growing seasons to be -200 ± 10 d during the mid-Holocene, 190± 6 d in MIS 3 and 160± 3 d during the last glacial period.