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

Citation

Piazza, Veronica; Ullmann, Clemens V.; Aberhan, Martin (2020), Data from: Ocean warming affected faunal dynamics of benthic invertebrate assemblages across the Toarcian Oceanic Anoxic Event in the Iberian Basin (Spain), Dryad, Dataset, https://doi.org/10.5061/dryad.66t1g1k0w

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.

Methods

Quantitative bed-by-bed sampling performed by consistently collecting the same amount of bulk rock for each sample. Fossils of benthic macroinvertebrates (mainly brachiopods and molluscs) were identified preferentially at species level and occurrences recorded in the field. Each taxon was assigned to a specific mode of life (combination of feeding, tiering and motility strategies).

The script file provides the codes used to carry out the analyses shown and discussed in the related paper. The analyses were performed in the R environment (v. 3.5.3). Information about the necessary R packages and other details regarding the script are included at the beginning of the script itself.

 

 

Funding

Deutsche Forschungsgemeinschaft, Award: AB 09/10-1

Natural Environment Research Council, Award: NE/N018508/1