Ediacaran–Cambrian bioturbation did not extensively oxygenate sediments in shallow marine ecosystems
Ediacaran–Cambrian bioturbation did not extensively oxygenate sediments in shallow marine ecosystems
复制标题
DOI：
10.1111/gbi.12550
复制
发表时间：
2023-02
期刊：
影响因子：
3.7
通讯作者：
Alison T. Cribb;S. J. van de Velde;W. Berelson;D. Bottjer;F. Corsetti
中科院分区：
文献类型：
--
作者：
Alison T. Cribb;S. J. van de Velde;W. Berelson;D. Bottjer;F. Corsetti
埃迪卡拉纪-寒武纪过渡时期的生物扰动辐射长期以来一直被假设为含氧沉积物，引发了可居住底栖动物带的扩张，并促进了早古生代底栖动物群落的动物分层。然而，就生物混合和生物灌溉的重要性而言，生物扰动对沉积物氧的影响尚未得到充分探讨，这两种生物扰动过程可能对沉积物氧化还原化学产生相反的影响。我们将埃迪卡拉纪和Terreneuvian的痕迹化石分类为生物混合或生物灌溉化石，并将生物扰动强度的沉积学指标与生物地球化学模拟相结合，模拟埃迪卡拉纪-寒武纪过渡时期的氧气渗透深度。最后，我们发现，尽管Terreneuvian的生物多样性急剧增加，但生物混合仍然是主要的生物扰动行为，与传统的假设相反，埃迪卡拉纪-寒武纪的生物扰动不太可能导致全球浅海沉积物的广泛氧化。
The radiation of bioturbation during the Ediacaran–Cambrian transition has long been hypothesized to have oxygenated sediments, triggering an expansion of the habitable benthic zone and promoting increased infaunal tiering in early Paleozoic benthic communities. However, the effects of bioturbation on sediment oxygen are underexplored with respect to the importance of biomixing and bioirrigation, two bioturbation processes which can have opposite effects on sediment redox chemistry. We categorized trace fossils from the Ediacaran and Terreneuvian as biomixing or bioirrigation fossils and integrated sedimentological proxies for bioturbation intensity with biogeochemical modeling to simulate oxygen penetration depths through the Ediacaran–Cambrian transition. Ultimately, we find that despite dramatic increases in ichnodiversity in the Terreneuvian, biomixing remains the dominant bioturbation behavior, and in contrast to traditional assumptions, Ediacaran–Cambrian bioturbation was unlikely to have resulted in extensive oxygenation of shallow marine sediments globally.