Ocean currents generate large footprints in marine palaeoclimate proxies.
Fossils of marine microorganisms such as planktic foraminifera are among the cornerstones of palaeoclimatological studies. It is often assumed that the proxies derived from their shells represent ocean conditions above the location where they were deposited. Planktic foraminifera, however, are carried by ocean currents and, depending on the life traits of the species, potentially incorporate distant ocean conditions. Here we use high-resolution ocean models to assess the footprint of planktic foraminifera and validate our method with proxy analyses from two locations. Results show that foraminifera, and thus recorded palaeoclimatic conditions, may originate from areas up to several thousands of kilometres away, reflecting an ocean state significantly different from the core site. In the eastern equatorial regions and the western boundary current extensions, the offset may reach 1.5 °C for species living for a month and 3.0 °C for longer-living species. Oceanic transport hence appears to be a crucial aspect in the interpretation of proxy signals.
ARC Centre of Excellence for Climate System Science and Climate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2010, Australia.
Erik
E
van Sebille
Earth and Climate Cluster, Faculty of Earth and Life Sciences, VU University, 1081 HV Amsterdam, The Netherlands.
Paolo
P
Scussolini
GEOMAR Helmholtz Centre for Ocean Research Kiel 24148 Kiel, Germany.
Jonathan V
JV
Durgadoo
Earth and Climate Cluster, Faculty of Earth and Life Sciences, VU University, 1081 HV Amsterdam, The Netherlands.
Frank J C
FJ
Peeters
GEOMAR Helmholtz Centre for Ocean Research Kiel 24148 Kiel, Germany.
Arne
A
Biastoch
Los Alamos National Laboratory, Los Alamos, New Mexico 87545.
Wilbert
W
Weijer
ARC Centre of Excellence for Climate System Science and Climate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2010, Australia.
Chris
C
Turney
Rosenstiel School for Marine and Atmospheric Science, University of Miami, Miami, FL 33149 Florida, USA.
Claire B
CB
Paris
1] Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain [2] Departament de Física, Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola), Spain.
Rainer
R
Zahn
D002980:Climate; D056908:Foraminifera / Q000502:physiology*; D005580:Fossils; D008962:Models, Theoretical; D009791:Oceanography / Q000379:methods; D009792:Oceans and Seas; D010933:Plankton / Q000166:cytology / Q000502:physiology*; D055110:Radiometric Dating; D014872:Water Movements