The Impact of the Latest Danian Event on Planktic Foraminiferal Faunas at ODP Site 1210 (Shatsky Rise, Pacific Ocean)

PLoS One. 2015 Nov 25;10(11):e0141644. doi: 10.1371/journal.pone.0141644. eCollection 2015.

Abstract

The marine ecosystem has been severely disturbed by several transient paleoenvironmental events (<200 kyr duration) during the early Paleogene, of which the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma) was the most prominent. Over the last decade a number of similar events of Paleocene and Eocene age have been discovered. However, relatively little attention has been paid to pre-PETM events, such as the "Latest Danian Event" ("LDE", ~62.18 Ma), specifically from an open ocean perspective. Here we present new foraminiferal isotope (δ13C, δ18O) and faunal data from Ocean Drilling Program (ODP) Site 1210 at Shatsky Rise (Pacific Ocean) in order to reconstruct the prevailing paleoceanographic conditions. The studied five-meter-thick succession covers ~900 kyr and includes the 200-kyr-lasting LDE. All groups surface dwelling, subsurface dwelling and benthic foraminifera show a negative δ13C excursion of >0.6‰, similar in magnitude to the one previously reported from neighboring Site 1209 for benthic foraminifera. δ18O-inferred warming by 1.6 to 2.8°C (0.4-0.7‰ δ18O measured on benthic and planktic foraminiferal tests) of the entire water column accompanies the negative δ13C excursion. A well stratified upper ocean directly before and during the LDE is proposed based on the stable isotope gradients between surface and subsurface dwellers. The gradient is less well developed, but still enhanced after the event. Isotope data are supplemented by comprehensive planktic foraminiferal faunal analyses revealing a dominance of Morozovella species together with Parasubbotina species. Subsurface-dwelling Parasubbotina shows high abundances during the LDE tracing changes in the strength of the isotope gradients and, thus, may indicate optimal living conditions within a well stratified surface ocean for this taxon. In addition, distinct faunal changes are reported like the disappearance of Praemurica species right at the base of the LDE and the continuous replacement of M. praeangulata with M. angulata across the LDE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Cycle
  • Climate
  • Climate Change
  • Foraminifera / metabolism*
  • Fossils
  • Pacific Ocean
  • Plankton

Grants and funding

Samples were supplied by the International Ocean Discovery Program. This research used samples and data provided by the ODP. The ODP was sponsored by NSF and participating countries under the management of Joint Oceanographic Institutions (JOI). Financial support was provided by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to AB (BO2505/8-1, EH 89/20). RPS and AD were supported by the Research Fund KU Leuven (OT/08/018). The authors acknowledge support from the Universität Leipzig within the program of Open Access Publishing.