Astronomically forced changes in chemical weathering and redox during the Anisian (Middle Triassic): Implications for marine ecosystem recovery following the end-Permian mass extinction

The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle–late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the Middle Triassic, Yunnan Province and southwest China shows this final stage of community assembly on the continental shelf. The fossil assemblage is a mixture of marine animals, including abundant lightly sclerotized arthropods, associated with fishes, marine reptiles, bivalves, gastropods, belemnoids, ammonoids, echinoderms, brachiopods, conodonts and foraminifers, as well as plants and rare arthropods from nearby land. In some ways, the Luoping biota rebuilt the framework of the pre-extinction latest Permian marine ecosystem, but it differed too in profound ways. New trophic levels were introduced, most notably among top predators in the form of the diverse marine reptiles that had no evident analogues in the Late Permian. The Luoping biota is one of the most diverse Triassic marine fossil Lagerstätten in the world, providing a new and early window on recovery and radiation of Triassic marine ecosystems some 10 Myr after the end-Permian mass extinction.

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Redox chemistry changes in the Panthalassic Ocean linked to the end-Permian mass extinction and delayed Early Triassic biotic recovery

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1610931114 ◽

2017 ◽

Vol 114 (8) ◽

pp. 1806-1810 ◽

Cited By ~ 30

Author(s):

Guijie Zhang ◽

Xiaolin Zhang ◽

Dongping Hu ◽

Dandan Li ◽

Thomas J. Algeo ◽

...

Keyword(s):

Mass Extinction ◽

Marine Ecosystem ◽

Redox Chemistry ◽

Global Ocean ◽

Upper Permian ◽

Western Canada ◽

Early Triassic ◽

Ecosystem Recovery ◽

Biotic Recovery ◽

Permian Mass Extinction

The end-Permian mass extinction represents the most severe biotic crisis for the last 540 million years, and the marine ecosystem recovery from this extinction was protracted, spanning the entirety of the Early Triassic and possibly longer. Numerous studies from the low-latitude Paleotethys and high-latitude Boreal oceans have examined the possible link between ocean chemistry changes and the end-Permian mass extinction. However, redox chemistry changes in the Panthalassic Ocean, comprising ∼85–90% of the global ocean area, remain under debate. Here, we report multiple S-isotopic data of pyrite from Upper Permian–Lower Triassic deep-sea sediments of the Panthalassic Ocean, now present in outcrops of western Canada and Japan. We find a sulfur isotope signal of negative Δ33S with either positive δ34S or negative δ34S that implies mixing of sulfide sulfur with different δ34S before, during, and after the end-Permian mass extinction. The precise coincidence of the negative Δ33S anomaly with the extinction horizon in western Canada suggests that shoaling of H2S-rich waters may have driven the end-Permian mass extinction. Our data also imply episodic euxinia and oscillations between sulfidic and oxic conditions during the earliest Triassic, providing evidence of a causal link between incursion of sulfidic waters and the delayed recovery of the marine ecosystem.

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Early and Middle Triassic trends in diversity, evenness, and size of foraminifers on a carbonate platform in south China: implications for tempo and mode of biotic recovery from the end-Permian mass extinction

Paleobiology ◽

10.1666/08082.1 ◽

2011 ◽

Vol 37 (3) ◽

pp. 409-425 ◽

Cited By ~ 57

Author(s):

Jonathan L. Payne ◽

Mindi Summers ◽

Brianna L. Rego ◽

Demir Altiner ◽

Jiayong Wei ◽

...

Keyword(s):

South China ◽

Mass Extinction ◽

Evolutionary Dynamics ◽

Middle Triassic ◽

Carbonate Platform ◽

Early Triassic ◽

Data Set ◽

Recovery Pattern ◽

Biotic Recovery ◽

Permian Mass Extinction

Delayed biotic recovery from the end-Permian mass extinction has long been interpreted to result from environmental inhibition. Recently, evidence of more rapid recovery has begun to emerge, suggesting the role of environmental inhibition was previously overestimated. However, there have been few high-resolution taxonomic and ecological studies spanning the full Early and Middle Triassic recovery interval, leaving the precise pattern of recovery and underlying mechanisms poorly constrained. In this study, we document Early and Middle Triassic trends in taxonomic diversity, assemblage evenness, and size distribution of benthic foraminifers on an exceptionally exposed carbonate platform in south China. We observe gradual increases in all metrics through Early Triassic and earliest Middle Triassic time, with stable values reached early in the Anisian. There is little support in our data set for a substantial Early Triassic lag interval during the recovery of foraminifers or for a stepwise recovery pattern. The recovery pattern of foraminifers on the GBG corresponds well with available global data for this taxon and appears to parallel that of many benthic invertebrate clades. Early Triassic diversity increase in foraminifers was more gradual than in ammonoids and conodonts. However, foraminifers continued to increase in diversity, size, and evenness into Middle Triassic time, whereas diversity of ammonoids and conodonts declined. These contrasts suggest decoupling of recovery between benthic and pelagic environments; it is unclear whether these discrepancies reflect inherent contrasts in their evolutionary dynamics or the differential impact of Early Triassic ocean anoxia or associated environmental parameters on benthic ecosystems.

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Ecosystem Recovery After the End-Permian Mass Extinction

The Paleontological Society Special Publications ◽

10.1017/s2475262200004020 ◽

1996 ◽

Vol 8 ◽

pp. 400-400 ◽

Cited By ~ 1

Author(s):

Richard J. Twitchett

Keyword(s):

Mass Extinction ◽

Ecosystem Recovery ◽

Permian Mass Extinction

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A new paleoecological look at the Dinwoody Formation (Lower Triassic, western USA): intrinsic versus extrinsic controls on ecosystem recovery after the end-Permian mass extinction

Journal of Paleontology ◽

10.1666/12-153 ◽

2013 ◽

Vol 87 (5) ◽

pp. 854-880 ◽

Cited By ~ 44

Author(s):

Richard Hofmann ◽

Michael Hautmann ◽

Hugo Bucher

Keyword(s):

United States ◽

Environmental Stress ◽

Beta Diversity ◽

Mass Extinction ◽

Western United States ◽

Ecosystem Recovery ◽

Diversity Pattern ◽

Marine Habitats ◽

Low Diversity ◽

Permian Mass Extinction

The Dinwoody Formation of the western United States represents an important archive of Early Triassic ecosystems in the immediate aftermath of the end-Permian mass extinction. We present a systematic description and a quantitative paleoecological analysis of its benthic faunas in order to reconstruct benthic associations and to explore the temporal and spatial variations of diversity, ecological structure and taxonomic composition throughout the earliest Triassic of the western United States. A total of 15 bivalve species, two gastropod species, and two brachiopod species are recognized in the study area. The paleoecological analysis shows that the oldest Dinwoody communities are characterized by low diversity, low ecological complexity and high dominance of few species. We suggest that this low diversity most likely reflects the consequences of the mass extinction in the first place and not necessarily the persistence of environmental stress. Whereas this diversity pattern persists into younger strata of the Dinwoody Formation in outer shelf environments, an increase in richness, evenness and guild diversity occurred around the Griesbachian–Dienerian boundary in more shallow marine habitats. This incipient recovery towards the end of the Griesbachian is in accordance with observations from other regions and thus probably represents an interregional signal. In contrast to increasing richness within communities (alpha-diversity), beta-diversity remained low during the Griesbachian and Dienerian in the study area. This low beta-diversity reflects a wide environmental and geographical range of taxa during the earliest Triassic, indicating that the increase of within-habitat diversity has not yet led to significant competitive exclusion. We hypothesize that the well-known prevalence of generalized taxa in post-extinction faunas is primarily an effect of reduced competition that allows species to exist through the full range of their fundamental niches, rather than being caused by unusual and uniform environmental stress.

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The main stage of recovery after the end-Permian mass extinction: taxonomic rediversification and ecologic reorganization of marine level-bottom communities during the Middle Triassic

PeerJ ◽

10.7717/peerj.11654 ◽

2021 ◽

Vol 9 ◽

pp. e11654

Author(s):

Evelyn Friesenbichler ◽

Michael Hautmann ◽

Hugo Bucher

Keyword(s):

Mass Extinction ◽

Middle Triassic ◽

Biotic Interactions ◽

Trophic Relationships ◽

Lag Phase ◽

Early Triassic ◽

Bottom Communities ◽

Extinction Event ◽

Mass Extinction Event ◽

Permian Mass Extinction

The recovery of marine life from the end-Permian mass extinction event provides a test-case for biodiversification models in general, but few studies have addressed this episode in its full length and ecological context. This study analyses the recovery of marine level-bottom communities from the end-Permian mass extinction event over a period of 15 Ma, with a main focus on the previously neglected main phase during the Middle Triassic. Our analyses are based on faunas from 37 lithological units representing different environmental settings, ranging from lagoons to inner, mid- and outer ramps. Our dataset comprises 1562 species, which belong to 13 higher taxa and 12 ecological guilds. The diversification pattern of most taxa and guilds shows an initial Early Triassic lag phase that is followed by a hyperbolic diversity increase during the Bithynian (early middle Anisian) and became damped later in the Middle Triassic. The hyperbolic diversity increase is not predicted by models that suggest environmental causes for the initial lag phase. We therefore advocate a model in which diversification is primarily driven by the intensity of biotic interactions. Accordingly, the Early Triassic lag phase represents the time when the reduced species richness in the wake of the end-Permian mass extinction was insufficient for stimulating major diversifications, whereas the Anisian main diversification event started when self-accelerating processes became effective and stopped when niche-crowding prevented further diversification. Biotic interactions that might drive this pattern include interspecific competition but also habitat construction, ecosystem engineering and new options for trophic relationships. The latter factors are discussed in the context of the resurgence of large carbonate platforms, which occurred simultaneously with the diversification of benthic communities. These did not only provide new hardground habitats for a variety of epifaunal taxa, but also new options for grazing gastropods that supposedly fed from microalgae growing on dasycladaceans and other macroalgae. Whereas we do not claim that changing environmental conditions were generally unimportant for the recovery of marine level-bottom communities, we note that their actual role can only be assessed when tested against predictions of the biotic model.

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Rapid enhancement of chemical weathering recorded by extremely light seawater lithium isotopes at the Permian–Triassic boundary

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1711862115 ◽

2018 ◽

Vol 115 (15) ◽

pp. 3782-3787 ◽

Cited By ~ 34

Author(s):

He Sun ◽

Yilin Xiao ◽

Yongjun Gao ◽

Guijie Zhang ◽

John F. Casey ◽

...

Keyword(s):

Mass Extinction ◽

Chemical Weathering ◽

Triassic Boundary ◽

Isotopic Signatures ◽

Siberian Traps ◽

Li Isotope ◽

Continental Weathering ◽

Excessive Nutrients ◽

Permian Mass Extinction ◽

Permian Triassic Boundary

Lithium (Li) isotope analyses of sedimentary rocks from the Meishan section in South China reveal extremely light seawater Li isotopic signatures at the Permian–Triassic boundary (PTB), which coincide with the most severe mass extinction in the history of animal life. Using a dynamic seawater lithium box model, we show that the light seawater Li isotopic signatures can be best explained by a significant influx of riverine [Li] with light δ7Li to the ocean realm. The seawater Li isotope excursion started ≥300 Ky before and persisted up to the main extinction event, which is consistent with the eruption time of the Siberian Traps. The eruption of the Siberian Traps exposed an enormous amount of fresh basalt and triggered CO2 release, rapid global warming, and acid rains, which in turn led to a rapid enhancement of continental weathering. The enhanced continental weathering delivered excessive nutrients to the oceans that could lead to marine eutrophication, anoxia, acidification, and ecological perturbation, ultimately resulting in the end-Permian mass extinction.

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