Ocean warming affected faunal dynamics of benthic invertebrate assemblages across the Toarcian Oceanic Anoxic Event in the Iberian Basin (Spain)

Abstract

The Toarcian Oceanic Anoxic Event (TOAE; Early Jurassic, ca. 182 Ma ago) represents one of the major environmental disturbances of the Mesozoic and is associated with global warming, widespread anoxia, and a severe perturbation of the global carbon cycle. Warming-related dysoxia-anoxia has long been considered the main cause of elevated marine extinction rates, although extinctions have been recorded also in environments without evidence for deoxygenation. We addressed the role of warming and disturbance of the carbon cycle in an oxygenated habitat in the Iberian Basin, Spain, by correlating high resolution quantitative faunal occurrences of early Toarcian benthic marine invertebrates with geochemical proxy data (δ18O and δ13C). We find that temperature, as derived from the δ18O record of shells, is significantly correlated with taxonomic and functional diversity and ecological composition, whereas we find no evidence to link carbon cycle variations to the faunal patterns. The local faunal assemblages before and after the TOAE are taxonomically and ecologically distinct. Most ecological change occurred at the onset of the TOAE, synchronous with an increase in water temperatures, and involved declines in multiple diversity metrics, abundance, and biomass. The TOAE interval experienced a complete turnover of brachiopods and a predominance of opportunistic species, which underscores the generality of this pattern recorded elsewhere in the western Tethys Ocean. Ecological instability during the TOAE is indicated by distinct fluctuations in diversity and in the relative abundance of individual modes of life. Local recovery to ecologically stable and diverse post-TOAE faunal assemblages occurred rapidly at the end of the TOAE, synchronous with decreasing water temperatures. Because oxygen-depleted conditions prevailed in many other regions during the TOAE, this study demonstrates that multiple mechanisms can be operating simultaneously with different relative contributions in different parts of the ocean.

Dating the evolution of the complex thalloid liverworts (Marchantiopsida): total‐evidence dating analysis supports a Late Silurian‐Early Devonian origin and post‐Mesozoic morphological stasis

“…Adding Ricciopsis ferganica , the oldest fossil for Ricciaceae (Moisan et al ., 2012), to the TED analysis resulted in a collapsed topology, underlining the utility of fossils with phylogenetic‐informative characters (Flores et al ., 2021a). As inferred here, upon including R. sandaolingensis , the radiation of Ricciaceae occurred 11–12 Ma after the Toarcian Oceanic Anoxic Event (T‐OAE, 182 Ma) marked by high global temperatures and seasonality (Xu et al ., 2018; Slater et al ., 2019; Piazza et al ., 2020). It is sensible to hypothesise that while T‐OAE was detrimental to mesophytic Marchantiales, Ricciaceae could have thrived in such context (Bischler & Jovet‐Ast, 1981).…”

Land-sea ecological connectivity during a Jurassic warming event

“…In basins from the Sub-Boreal and Tethyan Realm, however, other factors apart from anoxia and primary productivity seem to control changes in marine benthic communities through the early Toarcian (Danise et al, 2019;Piazza et al, 2020). It is worth noting, however, that none of these studies directly compare changes in primary productivity and changes in benthic communities from the same samples, so connectivity between these ecosystems has yet to be properly tested.…”

“…disappearance of dinoflagellates) at the onset of the CIE, and the subsequent dominance of terrestrially-derived palynomorphs (Danise et al, 2019). Otherwise, recorded declines in benthic diversity in relatively welloxygenated facies have been commonly interpreted as being related to an increase in temperature (Danise et al, 2019;Piazza et al, 2020). In such settings, recovery to ecologically stable and diverse faunal assemblages also occurs rapidly at the end of the CIE, synchronously with decreasing water temperatures (Danise et al, 2019;Piazza et al, 2020).…”

“…Otherwise, recorded declines in benthic diversity in relatively welloxygenated facies have been commonly interpreted as being related to an increase in temperature (Danise et al, 2019;Piazza et al, 2020). In such settings, recovery to ecologically stable and diverse faunal assemblages also occurs rapidly at the end of the CIE, synchronously with decreasing water temperatures (Danise et al, 2019;Piazza et al, 2020). In comparison with the Boreal Realm basins such as the Cleveland Basin, these data show that recovery of benthic fauna after the eTe was faster in areas that were less impacted by bottom water anoxia.…”

Spatial heterogeneity in benthic foraminiferal assemblages tracks regional impacts of paleoenvironmental change across Cretaceous OAE2

“…Global environmental changes impact ecosystems at global to regional scales, but biotic responses often vary based on local conditions (e.g., Leckie et al 1998; Seddon et al 2014; Danise et al 2019; Piazza et al 2020). Generalizing faunal responses to a given event among geographically widespread localities is challenging, because emergent faunal changes can be disparate, even if driven by a common factor (Seddon et al 2014).…”