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Reproducibility crisis and gravitation towards a consensus in ocean acidification research


Reproducibility is a persistent concern in science and recently attracts considerable attention in assessing biological responses to ocean acidification. Here we track the reproducibility of the harmful effects of ocean acidification on calcification of shell-building organisms by conducting a meta-analysis of 373 studies across 24 years. The pioneering studies tended to report large negative effects, but as other researchers assimilated this research into understanding their biological systems, the size of negative effects declined. Such declines represent a scientific process by which discoveries are initially assimilated and their limitations are subsequently explored. We suggest that scientific novelties can polarize a discipline where researchers fail to distinguish between different motivations for testing a phenomenon, that is, its existence (theory proposal) versus its influence within ever-widening contexts (theory development). Where context dependency is high, the lack of reproducibility may not represent a crisis but a part of theory development and eventual gravitation towards a consensus position.

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Fig. 1: Responses of marine calcifiers to ocean acidification in terms of calcification across the publication years.
Fig. 2: Potential factors that drive the effect sizes of calcification.
Fig. 3: Different methods of manipulation of seawater carbonate chemistry used for ocean acidification research across the publication years.
Fig. 4: Various taxa of marine calcifiers selected for ocean acidification research across the publication years.

Data availability

The datasets analysed in the current study are available in the Supplementary Information.

Code availability

The figures were created and analysed using a commercial software GraphPad Prism v.9.0.0, and the meta-analysis was conducted using an open-source software R version 4.3.0 with the metafor package version 4.2-0. The codes used to reproduce the meta-analysis are presented in the Supplementary Information.


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We acknowledge the Australian Research Council grant to S.D.C. (ARC DP230101932) and the funding from the National Natural Science Foundation of China to J.Y.S.L. (42176199, 42076121, M-0163, 42211530423). We thank N. K. M. Cheung for his advice on the statistical analyses used in this study.

Author information

Authors and Affiliations



S.D.C. and J.Y.S.L. conceived the study, interpreted the results and wrote the manuscript. J.Y.S.L. collected and analysed the data. S.D.C. provided in-depth interpretation of the data.

Corresponding authors

Correspondence to Sean D. Connell or Jonathan Y. S. Leung.

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The authors declare no competing interests.

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Nature Climate Change thanks the anonymous reviewers for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 Trends in the experimental protocol used for ocean acidification research across the publication years.

The scatter plots showing the gradual increases in (a) experimental duration and (b) average sample size used for experimentation across the years. Each dot represents an observation, whereas the solid grey line represents the best fit line of linear regression.

Extended Data Fig. 2 Assessment of potential publication bias based on funnel plot asymmetry.

The funnel plot showing the relationship between effect size and standard error using Egger’s regression test (two-sided, z = –10.8, p = 2.33 × 10–27). Each dot represents an observation.

Supplementary information

Supplementary Information

Supplementary Fig. 1, Tables 1 and 2 and Methods.

Reporting Summary

Supplementary Data 1

A comprehensive dataset of the studies included in the meta-analysis.

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Connell, S.D., Leung, J.Y.S. Reproducibility crisis and gravitation towards a consensus in ocean acidification research. Nat. Clim. Chang. 13, 1266–1271 (2023).

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