Timing and periodicity of Phanerozoic marine biodiversity and environmental change

Gareth G. Roberts,Philip D. Mannion

doi:10.1038/s41598-019-42538-7

Gareth G. Roberts, Philip D. Mannion

Open Access

https://doi.org/10.1038/s41598-019-42538-7

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Abstract

We examine how the history of Phanerozoic marine biodiversity relates to environmental change. Our focus is on North America, which has a relatively densely sampled history. By transforming time series into the time-frequency domain using wavelets, histories of biodiversity are shown to be similar to sea level, temperature and oceanic chemistry at multiple timescales. Fluctuations in sea level play an important role in driving Phanerozoic biodiversity at timescales >50 Myr, and during finite intervals at shorter periods. Subsampled and transformed marine genera time series reinforce the idea that Permian-Triassic, Triassic-Jurassic, and Cretaceous-Paleogene mass extinctions were geologically rapid, whereas the Ordovician-Silurian and Late Devonian ‘events’ were longer lived. High cross wavelet power indicates that biodiversity is most similar to environmental variables (sea level, plate fragmentation, δ18O, δ13C, δ34S and 87Sr/86Sr) at periods >200 Myr, when they are broadly in phase (i.e. no time lag). They are also similar at shorter periods for finite durations of time (e.g. during some mass extinctions). These results suggest that long timescale processes (e.g. plate kinematics) are the primary drivers of biodiversity, whilst processes with significant variability at shorter periods (e.g. glacio-eustasy, continental uplift and erosion, volcanism, asteroid impact) play a moderating role. Wavelet transforms are a useful approach for isolating information about times and frequencies of biological activity and commonalities with environmental variables.

Highlights

Biodiversity is regulated by some combination of biotic, geologic and climatic processes[1,2,3,4,5,6,7,8,9]
It would be useful to know if biodiversity experiences hysteresis, i.e. is there a lag between a change in an environmental variable and biodiversity? One way to approach this problem is to transform time series into the frequency domain
A benefit to using wavelet transforms is that signals can be reconstructed by summing the transform over scales

Summary

Introduction

Biodiversity is regulated by some combination of biotic, geologic and climatic processes[1,2,3,4,5,6,7,8,9]. Hannisdal & Peters[6] developed a probabilistic framework to assess whether time series were coupled and if certain signals (e.g. sea level) could be considered drivers of others (e.g. genera) This approach uses whole time series to assess ‘information transfer’ between signals, which is a significant advance over simple first-difference approaches. The transformed time series include number of marine genera and sedimentary rock packages in North America, isotopic ratios from marine carbonates at low latitudes (δ18O, δ13C, δ34S, 87Sr/86Sr) and estimates of continental flooding and plate fragmentation[6,24] (Fig. 1). We compare these power spectra to spectra calculated using a diversity estimate of North American marine genera. We use our results to suggest causal links between environmental variables and biodiversity

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Discussion

Conclusion