Influence of seasonal primary productivity on δ13C of North Atlantic deep-sea benthic foraminifera

The stable isotopic composition of benthic foraminifera has been widely used to reconstruct deep-ocean circulation, but questions have been raised about the influence of organic carbon flux on the carbon isotopic composition of deep-sea taxa. We show that annual and seasonality of primary productivity in the North Atlantic do not affect δ13C of Planulina wuellerstorfi, but that the intermittency or seasonality of primary production has a significant effect (0.9‰ change over 60° latitude) on δ13C of Epistominella exigua, reflecting the influence of pelagic-benthic coupling and microhabitat preferences on test geochemistry. These results support the use of δ13C of P. wuellerstorfi in paleocirculation studies and suggest that the δ13C of E. exigua can be used to reconstruct seasonality of productivity.