Relationship between pore density in benthic foraminifera and bottom-water oxygen content

► The pore density-to-oxygen-relationship in benthic foraminiferal species is investigated. ► A significant negative correlation between pore density and O2 is observed. ► This may indicate a morphological response of the foraminifers to decreasing oxygenation. ► We suggest that an increasing number of pores optimize the O2 uptake in low-oxygen environments. ► This morphological response can be used to establish an independent proxy for BW-O2.