Testing the deep-sea glacial disturbance hypothesis as a cause of low, present-day Norwegian Sea diversity and resulting steep latitudinal diversity gradient, using fossil records

Abstract

Within the intensively-studied, well-documented latitudinal diversity gradient, the deep-sea biodiversity of the present-day Norwegian Sea stands out with its notably low diversity, constituting a steep latitudinal diversity gradient in the North Atlantic. The reason behind this has long been a topic of debate and speculation. Most prominently, it is explained by the deep-sea glacial disturbance hypothesis, which states that harsh environmental glacial conditions negatively impacted Norwegian Sea diversities, which have not yet fully recovered. Our aim is to empirically test this hypothesis. Specific research questions are: (1) Has deep-sea biodiversity been lower during glacials than during interglacials? (2) Was there any faunal shift at the Mid-Brunhes Event (MBE) when the mode of glacial–interglacial climatic change was altered?