TY - JOUR
T1 - Secular changes in environmental stresses and eukaryotes during the Early Triassic to the early Middle Triassic
AU - Saito, Ryosuke
AU - Kaiho, Kunio
AU - Oba, Masahiro
AU - Tong, Jinnan
AU - Chen, Zhong Qiang
AU - Takahashi, Satoshi
AU - Chen, Jing
AU - Tian, Li
AU - Biswas, Raman Kumar
N1 - Funding Information:
This work was supported by a Global Centre of Excellence Program on Global Education and Research at the Centre for Earth and Planetary Dynamics, Tohoku University (led by E. Ohtani), and was funded by the Ministry of Education, Culture, Sports, Science and Technology, Japan and JSPS KAKENHI (grant no. 251482 to K.K.). ZQC's work was supported by the 111 Program of China (B08030) and by a research grant from Chengdu Center of China Geological Survey (No. 1212011220412 ). The researches of LT and JNT are supported by the National Natural Science Foundation of China (41172312, 41272372, 41302010). This is a contribution to IGCP 630. We thank K. Ito for assistance in the field.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - The Early Triassic, following the end-Permian mass extinction, was an interval of severe low diversity. Increasing amounts of evidence demonstrate that variable environmental stresses were widespread and intense after the end-Permian mass extinction. Here we report biomarkers from lowest Triassic to lower Middle Triassic strata in South China (Qingyan and Chaohu sections), including biomarkers for environmental stress (2-methyl hopane index) and eukaryotic algae (steranes and C21 n-alkylbenzene ratio). Using the 2-methyl hopane index, we detected the persistence of environmental stress during most of the Early Triassic. Using steranes and the C21 n-alkylbenzene ratio, we found a gradual increase in the biomass of eukaryotic algae during the Early to early Middle Triassic. A decrease in environmental stress in the Qingyan section (Leidapo Member) during the early Middle Triassic was synchronous with the "explosion" of the Qingyan Biota, which is characterized by a high abundance and diversity of invertebrate marine animals. Because the environmental stresses revealed by the 2-methyl hopane index encompass various factors (e.g., pH and temperature), we cannot identify the exact stresses at that time; however, our results reflect the amelioration of harsh environments for life during the interval of complete biotic recovery.
AB - The Early Triassic, following the end-Permian mass extinction, was an interval of severe low diversity. Increasing amounts of evidence demonstrate that variable environmental stresses were widespread and intense after the end-Permian mass extinction. Here we report biomarkers from lowest Triassic to lower Middle Triassic strata in South China (Qingyan and Chaohu sections), including biomarkers for environmental stress (2-methyl hopane index) and eukaryotic algae (steranes and C21 n-alkylbenzene ratio). Using the 2-methyl hopane index, we detected the persistence of environmental stress during most of the Early Triassic. Using steranes and the C21 n-alkylbenzene ratio, we found a gradual increase in the biomass of eukaryotic algae during the Early to early Middle Triassic. A decrease in environmental stress in the Qingyan section (Leidapo Member) during the early Middle Triassic was synchronous with the "explosion" of the Qingyan Biota, which is characterized by a high abundance and diversity of invertebrate marine animals. Because the environmental stresses revealed by the 2-methyl hopane index encompass various factors (e.g., pH and temperature), we cannot identify the exact stresses at that time; however, our results reflect the amelioration of harsh environments for life during the interval of complete biotic recovery.
KW - Cyanobacteria
KW - Delayed biotic recovery
KW - Early Triassic
KW - Eukaryotic algae
KW - Oceanic anoxia
KW - Organic geochemistry
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U2 - 10.1016/j.palaeo.2016.03.006
DO - 10.1016/j.palaeo.2016.03.006
M3 - Article
AN - SCOPUS:84962313501
VL - 451
SP - 35
EP - 45
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
SN - 0031-0182
ER -