Late Permian marine ecosystem collapse began in deeper waters: evidence from brachiopod diversity and body size changes

Abstract

Analysis of Permian-Triassic brachiopod diversity and body size changes from different water depths spanning the continental shelf to basinal facies in South China provides insights into the process of environmental deterioration. Comparison of the temporal changes of brachiopod diversity between deepwater and shallow-water facies demonstrates that deepwater brachiopods disappeared earlier than shallow-water brachiopods. This indicates that high environmental stress commenced first in deepwater settings and later extended to shallow waters. This environmental stress is attributed to major volcanic eruptions, which first led to formation of a stratified ocean and a chemocline in the outer shelf and deeper water environments, causing the disappearance of deep marine benthos including brachiopods. The chemocline then rapidly migrated upward and extended to shallow waters, causing widespread mass extinction of shallow marine benthos. We predict that the spatial and temporal patterns of earlier onset of disappearance/extinction and ecological crisis in deeper water ecosystems will be recorded during other episodes of rapid global warming.

Paleoecological Analysis of Benthic Recovery After the Late Permian Mass Extinction Event in Eastern Lombardy, Italy

“…Although the causal mechanisms remain the subject of considerable debate, most studies recognize that the extinction is associated with climate-induced environmental changes triggered by Siberian Trap volcanism (Algeo et al 2011;Burgess and Bowring 2015). Anoxia, euxinia, high sea-surface temperatures, and ocean acidification have been invoked as the leading drivers of extinctions in the oceans (e.g., Wignall and Twitchett 1996;Grice et al 2005;Knoll et al 2007;Kearsey et al 2009;Nabbefeld et al 2010;He et al 2015;Wignall et al 2016). However, other environmental changes, including increased sediment fluxes, eutrophication, and sea-level rise are thought to have contributed to the severity of the event (Algeo and Twitchett 2010;Algeo et al 2011;Schobben et al 2015).…”

Recovery pattern of brachiopods after the Permian–Triassic crisis in South China

“…According to previous studies (Feng and Jiang, 1978;Shen and He, 1994;Xu and Grant, 1994;Chen et al, 2002Chen et al, , 2005bHe et al, 2014b), at least 38 articulated brachiopod species were reported from the early Griesbachian to Spathian intervals after the end-Permian mass extinction. They are distributed widely in South China (Fig.…”

“…Recent studies (Chen et al, 2006a, b;He et al, 2014b) show that the early Griesbachian brachiopods in South China were distributed mainly in the Zhejiang Province (Meishan and Huangzhishan), Guizhou Province (Zhongzhai), Sichuan Province (Taipingshan) and Hunan Province (Rencunping) ( Fig. 1; Appendix A).…”

Estimating times of extinction in the fossil record

“…But nearly all analyses carried out thus far, including those in the past few years, have used first-generation methods [48][49][50][51]. Why have first-generation methods persisted?…”