Tracing energy inputs into the seafloor using carbonate sediments
Abstract
Carbonate rocks provide unique and valuable sedimentary archives for secular changes in Earth's physical, chemical, and biological processes. However, reading the stratigraphic record produces overlapping, nonunique interpretations that stem from the difficulty in directly comparing competing biological, physical, or chemical mechanisms within a common quantitative framework. We built a mathematical model that decomposes these processes and casts the marine carbonate record in terms of energy fluxes across the sediment–water interface. Results showed that physical, chemical, and biological energy terms across the seafloor are subequal and that the energetic dominance of different processes varies both as a function of environment (e.g., onshore vs. offshore) as well as with time-varying changes in seawater chemistry and with evolutionary changes in animal abundance and behavior. We applied our model to observations from the end-Permian mass extinction—a massive upheaval in ocean chemistry and biology—revealing an energetic equivalence between two hypothesized drivers of changing carbonate environments: a reduction in physical bioturbation increased carbonate saturation states in the oceans. Early Triassic occurrences of 'anachronistic' carbonates—facies largely absent from marine environments after the Early Paleozoic—were likely driven more by reduction in animal biomass than by repeated perturbations to seawater chemistry. This analysis highlighted the importance of animals and their evolutionary history in physically shaping patterns in the sedimentary record via their impact on the energetics of marine environments.
Additional Information
© 2023 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY). B.P.S. acknowledges the support from the Agouron Institute Postdoctoral Fellowship, W.W.F. acknowledges the support from the Caltech's Rothberg Innovative Initiative and the Caltech Center for Evolutionary Science, and S.M.E. thanks the Trimble Fellowship on the Geobiology of Complex Multicellular Life for supporting the early phase of this research. Author contributions: B.P.S. and W.W.F. designed research; B.P.S. and S.M.E. performed research; B.P.S. contributed new reagents/analytic tools; B.P.S. and S.M.E. analyzed data; and B.P.S., S.M.E., and W.W.F. wrote the paper. The authors declare no competing interest.Attached Files
Published - pnas.2215833120.pdf
Supplemental Material - pnas.2215833120.sapp.pdf
Supplemental Material - pnas.2215833120.sd01.xlsx
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Additional details
- PMCID
- PMC9992785
- Eprint ID
- 120725
- Resolver ID
- CaltechAUTHORS:20230411-695015900.5
- Agouron Institute
- Rothenberg Innovation Initiative (RI2)
- Caltech Center for Evolutionary Science
- Trimble Fellowship
- Created
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2023-05-01Created from EPrint's datestamp field
- Updated
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2023-07-21Created from EPrint's last_modified field
- Caltech groups
- Caltech Center for Evolutionary Science, Division of Geological and Planetary Sciences