| Titre | Recovery from persistent nutrient-N limitation following the Permian-Triassic mass extinction |
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| Auteur | Du, Y; Grasby, S E ; Xing, T; Song, H; Tien, L; Chu, D; Wu, Y; Dal Corso, J; Algeo, T; Tong, J |
| Source | Earth and Planetary Science Letters vol. 602, 117944, 2023 p. 1-12, https://doi.org/10.1016/j.epsl.2022.117944 |
| Image |  |
| Année | 2023 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20220395 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.epsl.2022.117944 |
| Media | papier; numérique; en ligne |
| Formats | pdf; html |
| Région | South China |
| Lat/Long OENS | 99.0000 122.0000 33.0000 20.0000 |
| Sujets | Bassin de Nanpanjiang ; Sciences et technologie; Nature et environnement |
| Illustrations | cartes de localisation; représentations graphiques combinées; diagrammes; diagrammes |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Terrane Pearya, Ellesmere nord de l'ouest de l'Arctique |
| Diffusé | 2023 01 15 |
| Résumé | (disponible en anglais seulement)
Global warming, widespread oceanic anoxia and stagnation, and large perturbations of the global carbon cycle characterized the end-Permian to Middle Triassic
interval. Nitrogen isotopes of marine sediments (15Nbulk) decreased through the Permian–Triassic transition, implying development of nitrate-limited and ammonium-dominated conditions (i.e., anaerobic marine N cycle) in Early Triassic oceans, which
may have contributed to the delay in marine biotic recovery following the end-Permian mass extinction. However, the temporal evolution of the nitrogen cycle and the role of nutrient supply in marine ecosystem recovery during this interval remain
poorly understand. Here, we present a new high-resolution Permian–Triassic nitrogen isotope curve from the Nanpanjiang Basin of South China. Low 15N (+2%0 to +2%0) during the Griesbachian-to-Smithian substages (i.e., first ~2 Myr of Early Triassic)
reflects enhanced nitrogen fixation concurrently with climatic hyperwarming and expansion of oceanic anoxia. A large rise in 15N (to +8%0) followed by a decline (to -2%0) reflects an aborted recovery of the marine N cycle during the Spathian substage
of the Early Triassic. During the Middle Triassic N fluctuations between +1%0 and +4%0 during the Anisian Stage, followed by stabilization around +4%0 in the Ladinian Stage, suggest a slow stepwise re-establishment of the aerobic marine N cycle.
Although both South China and northwestern Pangea experienced a transition to anaerobic N cycling during the Early Triassic, South China experienced an earlier and more rapid onset of this event as well as larger N-cycle fluctuations during the
recovery interval than northwestern Pangea. Overall, N cycle changes coincided with those in paleotemperature and ocean-redox state, demonstrating an integrated response of the marine system to the extreme environmental perturbations of the Early
Triassic. In summary, our results support persistence of nutrient-N-limited conditions and strong microbial N-fixation throughout the Early Triassic, with a full return to the aerobic N cycle only after stabilization of oceanic environmental
conditions during the Middle Triassic. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Nitrogen is a critical element that is often the limiting nutrient in the oceans. Changes in nitrogen supply have a direct impact on total
marine bioproductivity. This in turn impacts the potential of petroleum source rocks as well as factors such as phosphate and critical element deposition. As part of GEM research, it has been shown that the global hothouse climate developed after the
Permian mass extinction (the largest in Earth history). This was followed by a 7 million year period of very restricted bioproductivity in the global oceans, and then finally a recovery that began in the Middle Triassic with heavy deposition of
organic-rich rocks. This study expands to examine the global extent of this nutrient limitation event. The results show that it was indeed global and that the greenhouse leak event significantly limited marine production. |
| GEOSCAN ID | 331126 |
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