How disastrous was Oceanic Anoxic Event 2? A shelf versus deep-sea comparison from the echinoderm perspective

点击翻译按钮获取中文摘要

The deep sea is by far the most widespread environment on the planet, yet our knowledge on thecomposition, biodiversity and the origin of the deep-sea biota remains remarkably poor. Particularlyobscure is the geological history and the evolutionary dynamics of the present-day macrobenthos. Thedeep-sea biota is either relatively recent, resulting from multiple turnovers linked to large disruptions ofthe deep sea environment, or it is ancient and presumably resilient to such changes. The reason whythis debate is unsettled is the lack of direct evidence on the geological history of deep-seamacrobenthos due to the absence of outcrops of deep-sea sediments with preserved fossil remains.Recently, we have identified an unexpected possibility to investigate the evolution of deep-seamacrobenthos and provide key direct evidence to assess the evolutionary origin of the deep-seaecosystems. In a pilot study, we have discovered significant quantities of identifiable skeletal remainsof fossil echinoderms in mid-Cretaceous sediments recovered by the Ocean Drilling Program. In thisproject we will build on this discovery and use DSDP/ODP material to systematically assess thecomposition and diversity of Lower Cretaceous deep-sea echinoderm communities in order to testwhether they significantly differ from modern equivalents and when the last major reorganisation of thedeep-sea fauna took place. This project gives a new perspective to ODP/DSDP material that could setoff an entirely new range of applications based on the microfossil record of macrobenthic groups.