The EECO (ca 53-49 Ma) is a crucial interval of time to explore the marine biota response to past global warming as it records the Earth temperatures and pCO2 peak of the entire Cenozoic Era. The unicellular planktic foraminifera are a major group of open-marine calcifiers to investigate in this view as a group extremely sensitive to paleoenvironmental changes and largely utilized in biostratigraphy. Recent studies highlight that the EECO significantly impacted the abundance and diversity of the symbiont-bearing genus Morozovella. This genus, close to the carbon isotope excursion (CIE) known as J event, markedly and permanently decreased in abundance and diversity in the Atlantic and Pacific Oceans whereas abundance and diversity of genus Acarinina concomitantly increased. In addition, Morozovella species switched their coiling direction (the ability to add chambers in clock or counter clock-wise) from dominantly dextral to dominantly sinistral within 200-400 kyrs after the CIE K/X event, whereas Acarinina maintains both below and within the EECO rather proportional dextral and sinistral coiling direction. The detailed record from Atlantic and Pacific Oceans also underlines diachroneities among planktic foraminiferal biohorizons. We decided to explore planktic foraminiferal biostratigraphy, quantitative abundance and coiling direction from Site 762 C (Exmouth Plateau). This site, though affected by some core breaks, records several CIEs below and within the EECO. The study of this site is essential to outline a global perspective of planktic foraminiferal response to the EECO due to its far southern high latitude location of northwest margin of Australia. Our dataset provides new biostratigraphic data suitable for a required Eocene zonal scheme revision and new insights on the resilience of planktic foraminifera from southern Indian Ocean, essential for a more comprehensive understanding of past global warming events in light of the current climate changes.
Planktic foraminiferal response to the Early Eocene Climatic Optimum (EECO, ca 53-49Ma): biostratigraphy and quantitative abundances from Hole 762C (Exmouth Plateau, Indian Ocean)
Filippi G.Primo
Writing – Original Draft Preparation
;D’Onofrio Roberta.Secondo
Data Curation
;Luciani V.Ultimo
Writing – Review & Editing
2022
Abstract
The EECO (ca 53-49 Ma) is a crucial interval of time to explore the marine biota response to past global warming as it records the Earth temperatures and pCO2 peak of the entire Cenozoic Era. The unicellular planktic foraminifera are a major group of open-marine calcifiers to investigate in this view as a group extremely sensitive to paleoenvironmental changes and largely utilized in biostratigraphy. Recent studies highlight that the EECO significantly impacted the abundance and diversity of the symbiont-bearing genus Morozovella. This genus, close to the carbon isotope excursion (CIE) known as J event, markedly and permanently decreased in abundance and diversity in the Atlantic and Pacific Oceans whereas abundance and diversity of genus Acarinina concomitantly increased. In addition, Morozovella species switched their coiling direction (the ability to add chambers in clock or counter clock-wise) from dominantly dextral to dominantly sinistral within 200-400 kyrs after the CIE K/X event, whereas Acarinina maintains both below and within the EECO rather proportional dextral and sinistral coiling direction. The detailed record from Atlantic and Pacific Oceans also underlines diachroneities among planktic foraminiferal biohorizons. We decided to explore planktic foraminiferal biostratigraphy, quantitative abundance and coiling direction from Site 762 C (Exmouth Plateau). This site, though affected by some core breaks, records several CIEs below and within the EECO. The study of this site is essential to outline a global perspective of planktic foraminiferal response to the EECO due to its far southern high latitude location of northwest margin of Australia. Our dataset provides new biostratigraphic data suitable for a required Eocene zonal scheme revision and new insights on the resilience of planktic foraminifera from southern Indian Ocean, essential for a more comprehensive understanding of past global warming events in light of the current climate changes.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
