DOI: 10.5061/dryad.brv15dvdr
title: Oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum

description: The global ocean’s oxygen (O2) inventory is declining in response to
 global warming, but the future of the low-oxygen tropics is uncertain. We
 present new evidence for tropical oxygenation during the Paleocene-Eocene
 Thermal Maximum (PETM), a warming event that serves as a geologic analogue
 to anthropogenic warming. Foraminifera-bound nitrogen isotopes indicate
 that the tropical North Pacific oxygen-deficient zone contracted during
 the PETM. A concomitant increase in foraminifera size implies that oxygen
 availability rose in the shallow subsurface throughout the tropical North
 Pacific. These changes are consistent with ocean model simulations of
 warming, in which a decline in biological productivity allows tropical
 subsurface oxygen to rise even as global ocean oxygen declines. The
 tropical oxygen increase may have helped avoid a mass extinction during
 the PETM.
description: Moretti_et_al_2023_DataS1.csv  Fossil
 foraminifera were manually separated from the sediment fraction above 150
 micrometres. Nitrogen isotope composition of organic linings encased in
 planktic foraminifera calcite (FB-δ<sup>15</sup>N) was
 measured with the persulfate-denitrifier method. Acid dissolution of
 foraminifera shells and potassium persulfate oxydation of organic linings
 were performed according to the methodology of Ren et al., 2009, with the
 subsequent modifications outlined in Leichliter et al., 2021. Analysis of
 FB-δ<sup>15</sup>N was performed through the denitrifier
 method and measured in an IRMS MAT253 coupled with a customized gas-bench
 (Sigman et al., 2001; Weigand et al., 2016).
 Moretti_et_al_2023_DataS2.csv  Seawater
 pO<sub>2</sub> is reconstructed by applying a trait-based
 physiological model for the response of foraminifera shell size to changes
 in temperature and oxygen. For our computations, we used published
 planktic and benthic foraminifera size records (Petrizzo et al., 2007;
 Kaiho et al., 2006) and reconstructed sea surface temperatures (Zachos et
 al., 2003). See "Related works".
description: **Metadata** **Oxygen rise in the tropical upper ocean during the
 Paleocene-Eocene Thermal Maximum** **Authors** Simone Moretti, Alexandra
 Auderset, Curtis Deutsch, Ronja Schmitz, Lukas Gerber, Ellen Thomas,
 Valeria Luciani, Maria Rose Petrizzo, Ralf Schiebel, Aradhna Tripati,
 Philip Sexton, Richard Norris, Roberta DOnofrio, James Zachos, Daniel M.
 Sigman, Gerald H. Haug, Alfredo Martnez-Garca **File list**
 Moretti_et_al_2023_DataS1.csv Moretti_et_al_2023_DataS2.csv **File
 descriptions** Moretti_et_al_2023_DataS1.csv This file contains all the
 nitrogen isotope data and nitrogen content of planktic foraminifera
 presented in this work from ODP Sites 1263, 1210, 1209, 690, 865 and DSDP
 Site 213. For site 1263, a composite depth scale is provided as the data
 is based on two individual drilling holes. *Columns* of*
 Moretti_et_al_2023_DataS1.csv: * *Sample ID*: The unique identifier of the
 sample used according to the International Ocean Drilling Program (IODP)
 terminology. These identifiers are typically created by curators of IODP
 core repositories at the time of sediment core sampling. * *Depth mbsf
 (m)*: mbsf stays for meters below sea floor, and it represent the depth
 scale that is the basis for any subsequent processing such as the creation
 of an age model or of a composite depth in case more than one depth scale
 have to be combined. * *Relative age (kyr)*: Age (in thousands of years)
 with respect to the onset of the Paleocene Eocene Thermal Maximum.
 Negative values represent time before the onset of the PETM and positive
 values represent times after the onset. * *Foram type*: the type of
 foraminifera that was analyzed for nitrogen isotopes. There are three
 dominant taxa in the PETM, *Morozovella*, *Acarinina* and *Subbotina*. *
 *N content (nmol/mg)*: The amount of foram-bound nitrogen contained in
 each milligram of cleaned foraminifera calcite. * *FB-15N ()*: The
 nitrogen isotopic composition of the foram-bound organic matter in
 standard permil notation. * *Foraminifera Size (m)*: The size range in
 which planktic foraminifera were collected and subsequently analyzed. *
 *Depth rmcd (m)*: revised meter of composite depth, this is provided only
 for site 1263, as our dataset for this Site is based on two individual
 holes (C, D), and thus two individual depth scales that are combined into
 a single composite one. * Moretti_et_al_2023_DataS2.csv This file contains
 seawater pO2 estimations for the deep ocean-dwelling trochospiral benthic
 foraminifera and upper ocean-dwelling planktic foraminifera based on the
 metabolic model presented in this work. * *Columns* of*
 Moretti_et_al_2023_DataS2.csv: * *Sample ID*: The unique identifier of the
 sample used according to the International Ocean Drilling Program (IODP)
 terminology. These identifiers are typically created by curators of IODP
 core repositories at the time of sediment core sampling. * *Depth mbsf
 (m)*: mbsf stays for meters below sea floor, and it represent the depth
 scale that is the basis for any subsequent processing such as the creation
 of an age model or of a composite depth in case more than one depth scale
 have to be combined. * *Relative age (kyr)*: Age (in thousands of years)
 with respect to the onset of the Paleocene Eocene Thermal Maximum.
 Negative values represent time before the onset of the PETM and positive
 values represent times after the onset. * *Source benthic foraminifera
 size data*: the source publication where foraminifera size data was used
 for computation of changes in environmental deep ocean oxygen partial
 pressure (see Related works). * *Deep ocean relative pO2:* reconstructed
 relative change in oxygen partial pressure in the deep ocean with respect
 to pre-PETM values.* * *Source planktic foraminifera size data*: the
 source publication where foraminifera size data was used for computation
 of changes in environmental upper ocean oxygen partial pressure (see
 Related works). * *M. subbotinae relative pO2, M. pasionensis relative
 pO2, M. occlusa relative pO2, M. velascoensis relative pO2, S.
 velascoensis relative pO2, A. soldadoensis relative pO2, S. velascoensis
 relative pO2, S. triangularis relative pO2, S. inaequispira relative pO2:*
 these columns represent the reconstructed relative change in oxygen
 partial pressure in the surface ocean with respect to pre-PETM values for
 each of the listed species. **Methods for dataset collection** *
 Moretti_et_al_2023_DataS1.csv: Fossil foraminifera were manually separated
 from the sediment fraction above 150 micrometres. Nitrogen isotope
 composition of organic linings encased in planktic foraminiferacalcite
 (FB-15N) was measured with the persulfate-denitrifier method. Acid
 dissolution of foraminifera shells and potassium persulfate oxydation of
 organic linings were performed according to the methodology of Ren et al.,
 2009, with the subsequent modifications outlined in Leichliter et al.,
 2021. Analysis of FB-15N was performed through the denitrifier methodand
 measured in a IRMS MAT253 coupled with customized gas-bench (Sigman et
 al., 2001; Weigand et al., 2016). * Moretti_et_al_2023_DataS2.csv:
 Seawater pO2 is reconstructed by applying a trait-based physiological
 model for the response of foraminifera shell size to changes in
 temperature and oxygen. For our computations, we used published planktic
 and benthic foraminifera size records (Petrizzo et al., 2007; Kaiho et
 al., 2006) and reconstructed sea surface temperatures (Zachos et al.,
 2003). See Related works. **Related works:** *
 *
 *
 **Additional info:** cells
 filled with "n/a" contain no data When importing the .csv files
 in software like Microsoft Excel, use comma as the delimiter for correct
 visualization.