Carbon isotope (δ13C) differences between Late Cretaceous ammonites and benthic mollusks from Antarctica
Carbon isotope (δ13C) differences between Late Cretaceous ammonites and benthic mollusks from Antarctica
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DOI：
10.1016/j.palaeo.2015.03.034
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发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
T. Tobin;P. Ward
中科院分区：
文献类型：
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作者：
T. Tobin;P. Ward
菊石是中生代最常见的化石之一，但对其生命方式却鲜有共识。同位素研究已用于根据 δ18O 测量值重建其首选水温，但 δ13C 值的解释更为模糊。先前的研究记录了菊石和底栖生物之间 δ13C 值的种群差异，但没有详细解释原因。在这里，我们检查了南极洲西摩岛的一个软体动物群落，发现菊石和其他底栖软体动物之间存在 4‰ 的碳同位素偏移。造成这种异常的最可能原因是与其他软体动物相比，菊石壳材料的代谢碳贡献增加，但我们不能排除甲烷渗漏贡献的可能性。更积极的生活方式和增加的能量需求可能会增加呼吸二氧化碳的产生，这可能增加了菊石对白垩纪末期大规模灭绝的敏感性。
Ammonites are one of the most common fossils of the Mesozoic, but there is little consensus on their mode of life. Isotopic studies have been used to reconstruct their preferred water temperature from δ18O measurements, but δ13C values have more ambiguous interpretations. Previous studies have recorded population differences in δ13C values between ammonite and benthic organisms without explaining the cause in detail. Here we examine a molluscan community from Seymour Island, Antarctica and find a 4‰ carbon isotope offset between ammonites and other benthic mollusks. The most likely cause of this anomaly is an increased metabolic carbon contribution to ammonite shell material when compared with other mollusks, but we cannot rule out the possibility of a methane seep contribution. Increased respired CO2production could be generated by a more active lifestyle and increased energy demands, which may have increased the susceptibility of ammonites to the end Cretaceous mass extinction.