TY - JOUR
T1 - Nannoplankton malformation during the Paleocene-Eocene Thermal Maximum and its paleoecological and paleoceanographic significance
AU - Bralower, Timothy J.
AU - Self-Trail, Jean M.
N1 - Funding Information:
Research funded by NSF OCE-1416663. We appreciate a long-term loan of slides from Bass River from Samantha Gibbs. We acknowledge helpful discussions with Lee Kump. An earlier draft of the manuscript benefitted from the reviews of Laurel Bybell and Marci Robinson, and we acknowledge constructive reviews by Tom Dunkley Jones and an anonymous reviewer. All data are included in the supporting information and available at https://www.pangaea.de/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Publisher Copyright:
©2016. American Geophysical Union. All Rights Reserved.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - The Paleocene-Eocene Thermal Maximum (PETM) is characterized by a transient group of nannoplankton, belonging to the genus Discoaster. Our investigation of expanded shelf sections provides unprecedented detail of the morphology and phylogeny of the transient Discoaster during the PETM and their relationship with environmental change. We observe a much larger range of morphological variation than previously documented suggesting that the taxa belonged to a plexus of highly gradational morphotypes rather than individual species. We propose that the plexus represents malformed ecophenotypes of a single species that migrated to a deep photic zone refuge during the height of PETM warming and eutrophication. Anomalously, high rates of organic matter remineralization characterized these depths during the event and led to lower saturation levels, which caused malformation. The proposed mechanism explains the co-occurrence of malformed Discoaster with pristine species that grew in the upper photic zone; moreover, it illuminates why malformation is a rare phenomenon in the paleontological record.
AB - The Paleocene-Eocene Thermal Maximum (PETM) is characterized by a transient group of nannoplankton, belonging to the genus Discoaster. Our investigation of expanded shelf sections provides unprecedented detail of the morphology and phylogeny of the transient Discoaster during the PETM and their relationship with environmental change. We observe a much larger range of morphological variation than previously documented suggesting that the taxa belonged to a plexus of highly gradational morphotypes rather than individual species. We propose that the plexus represents malformed ecophenotypes of a single species that migrated to a deep photic zone refuge during the height of PETM warming and eutrophication. Anomalously, high rates of organic matter remineralization characterized these depths during the event and led to lower saturation levels, which caused malformation. The proposed mechanism explains the co-occurrence of malformed Discoaster with pristine species that grew in the upper photic zone; moreover, it illuminates why malformation is a rare phenomenon in the paleontological record.
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U2 - 10.1002/2016PA002980
DO - 10.1002/2016PA002980
M3 - Article
AN - SCOPUS:84995695240
VL - 31
SP - 1423
EP - 1439
JO - Paleoceanography and Paleoclimatology
JF - Paleoceanography and Paleoclimatology
SN - 0883-8305
IS - 10
ER -