This study reveals moderate yet important variations in coccolith and central unit size throughout the Aptian–late Cenomanian (27 my) time interval in western Tethys. A new statistical approach was applied to determine whether non-random size trends apply to these metrics and to identify possible links between their variation and fertility or temperature. During OAE 1a, coccoliths were the smallest and the most elliptical, with reduced central unit size. A further minor size decrease occurs during OAE 1b but not during OAE 1d. From the middle Albian to the middle Cenomanian, larger and less elliptical coccoliths are observed, with unchanged central unit dimensions. These results, together with concomitantly larger size changes in confirm that is a tolerant taxon. High-frequency, high-amplitude paleoenvironmental changes during the Aptian–early Albian indicate that temperature and fertility – either individually or in combination – had no direct impact on the mean coccolith size and potentially other factors affected coccolith size. Instead, lower nutrients with lower temperatures probably played a role in promoting larger but smaller coccoliths during the middle Albian–Cenomanian. The size and ellipticity changes during OAE 1a and 1b were the strongest, likely resulting from ocean acidification and trace metal inputs, in addition to (or independently of) fertility and temperature variations.

中文翻译：

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白垩纪中期 Watznaueria barnesiae 的形态变化：古生态学意义

这项研究揭示了特提斯洋西部整个阿普第期至塞诺曼期晚期（27 my）时间间隔内的颗石和中心单元大小的中等但重要的变化。应用一种新的统计方法来确定非随机大小趋势是否适用于这些指标，并确定它们的变化与生育力或温度之间可能的联系。在 OAE 1a 期间，颗石石是最小且最椭圆的，中心单元尺寸减小。在 OAE 1b 期间，尺寸进一步减小，但在 OAE 1d 期间则没有。从阿尔布阶中期到塞诺曼阶中期，观察到较大且较小椭圆形的颗石岩，其中心单元尺寸未发生变化。这些结果，加上随之而来的较大的尺寸变化，证实了它是一个具有耐受性的分类群。 Aptian期-早期阿尔布阶期的高频、高幅度的古环境变化表明，温度和肥力（无论是单独还是组合）对平均颗石大小没有直接影响，并且可能有其他因素影响颗石大小。相反，在阿尔布阶-塞诺曼阶中期，较低的营养物质和较低的温度可能在促进较大但较小的球石形成方面发挥了作用。 OAE 1a 和 1b 期间的大小和椭圆度变化最强，除了（或独立于）肥力和温度变化之外，可能是由于海洋酸化和微量金属输入造成的。