Impact of the Late Lutetian Thermal Maximum (41.52 Ma) on plankticforaminiferal assemblages (Site 1263, Atlantic Ocean)

The short-lived (~30 Kyr) warming C19r event or Late Lutetian Thermal Maximum (LLTM) is the hyperthermal recorded 41.52 Ma ago in the upper part of
magnetochron C19r. Like most Eocene hyperthermals, this event has been defined by a sharp negative excursion in the oxygen and carbon isotopic records in the Atlantic Ocean, including ODP Sites 1260, 1263 and 702 and in a land section in Spain. To understand how marine biota responded to past warming is crucial also for a future climatic perspective. However, differently from the early Eocene hyperthermals for which biotic response has been widely analyzed, the LLTM has been so far explored only for the benthic foraminiferal response. Planktic foraminifera, that are extremely sensitive to ocean changes, have a key role to evaluate how global warming affects marine ecosystems. We present here the impact on planktic foraminiferal communities to this event, at the south Atlantic Site 1263. Although the LLTM records a moderate temperature increase with respect to other Eocene warming events, planktic foraminiferal assemblages reveal to be extreme sensitive as showing marked variations that include a decline in abundance of the cold-index Subbotina and a not straightforward response of the mixed-layer warm-index taxa, suggesting possible ecological competition and different flexibility to challenge the new environmental conditions.