DOI: 10.5061/dryad.p32p0
title: Data from: Exploring photosymbiotic ecology of planktic foraminifers from chamber-by-chamber isotopic history of individual foraminifers

description: Evolution of photosymbiotic ecology is an important adaptation for
 planktic foraminifers that enhances the ecological advantage of living in
 oligotrophic oceans. Therefore, detecting photosymbiotic ecology in fossil
 species is one of the keys to understanding the paleobiodiversity dynamics
 of planktic foraminifers. Because foraminiferal tests record the
 ontogenetic history of ecological information in geochemical signatures,
 analyzing individual geochemical profiles with growth can reveal a
 species’ ecology. This study examined chamber-by-chamber stable isotopes
 (δ13C and δ18O) of foraminiferal individuals to identify photosymbiotic
 signals. We observed an ontogenetic δ13C increase of up to 2.4‰,
 accompanied by relatively stable, negative δ18O, in the symbiotic species
 Globigerinoides conglobatus and Globigerinoides sacculifer. In contrast,
 δ13C and δ18O showed significant positive correlation during ontogeny in
 the asymbiotic species Globorotalia truncatulinoides. These two ecological
 groups produce contrasting isotopic profiles, thereby allowing us to use
 our ontogenetic isotopic analyses of individual specimens to identify
 algal photosymbiosis in fossil foraminifers. The chamber-by-chamber
 isotope analyses with individual ontogeny have great advantages in
 analyzing rare species because only one individual is required to describe
 ontogenetic isotopic history. In addition to photosymbiotic
 identification, our methods hold great potential to provide new insight
 into species paleoecological studies such as the ontogenetic history of
 calcification depth.
description: Supplementary Figure
 1Location map (A),
 seasonal temperature and salinity difference (B), and depth profiles of
 each physical and chemical property of the water column (C–I). For (C) and
 (D), in addition to National Oceanographic Data Center (NODC) Cruise
 Station 127 (black square), two Argo stations are selected as references
 (March, 2013 and September 2013), representing summer and winter
 conditions, respectively (see Supplementary Tables 1 and 2 for detailed
 information). (H) represents estimated δ18O values of equilibrium calcite
 calculated from temperature and salinity using equations of LeGrande and
 Schmidt (2006) and Kim and O’Niel (1997). δ18Οcal; δ18O values of
 equilibrium calcite. δ13CDIC; δ13C values of dissolved inorganic carbon.
 NODC; National Oceanographic Date Center. Stn; Station. Argo floats data
 (WMO (World Meteorological Organisation) ID: 5901905) are cited from
 Global Data Assembly Centre (Argo GDAC)
 (ftp://ftp.ifremer.fr/ifremer/argo/dac/aoml/5901905/). Vertical
 oceanographic data of Station 127 are cited from the World Ocean Database
 2009 (http://www.nodc.noaa.gov/OC5/WOD09/pr_wod09.html). Kim, S. T., and
 J. R. O’Niel. 1997. Equilibrium and nonequilibrium oxygen isotope effects
 in synthetic carbonates. Geochimica et Cosmochimica Acta 61:3461–3475.
 LeGrande, A.N., and G.A. Schmidt. 2006. Global gridded data set of the
 oxygen isotopic composition in seawater. Geophysical Research Letters
 33:L12604.Supplementary Table
 1Water column
 characteristics near study site. Data are from the World Ocean Database
 2009 (http://www.nodc.noaa.gov/OC5/WOD09/pr_wod09.html). δ18O values of
 sea water (δ18OSW) were calculated from salinity using regional
 δ18O–salinity relationship in South Pacific (LeGrande and Schmidt, 2006).
 Then from the δ18OSW and temperature, δ18O values of equilibrium calcite
 (δ18Ocal) are calculated using equations of Kim and O’Niel
 (1997).Supplementary Table
 2Argo
 float data (WMO ID: 5901905) of two selected stations representing summer
 (May 2013) and winter (September 2013) water column properties. These data
 are plotted in Supplementary Figure 1-C and -D.