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Early plant organics increased global terrestrial mud deposition through enhanced flocculation

Zeichner, Sarah S. and Nghiem, Justin and Lamb, Michael P. and Takashima, Nina and de Leeuw, Jan and Ganti, Vamsi and Fischer, Woodward W. (2021) Early plant organics increased global terrestrial mud deposition through enhanced flocculation. Science, 371 (6528). pp. 526-529. ISSN 0036-8075.

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An irreversible increase in alluvial mudrock occurred with the Ordovician-Silurian evolution of bryophytes, challenging a paradigm that deep-rooted plants were responsible for this landscape shift. We tested the idea that increased primary production and plant organics promoted aggregation of clay into flocs in rivers and facilitated mud deposition on floodplains. In experiments, we observed that clay readily flocculated for organic and clay concentrations common to modern rivers, yielding settling velocities three orders of magnitude larger than those without organics. Using a transport model, we found that flocculation substantially increased mud deposition, resulting in muddier floodplains. Thus, organic-induced flocculation may have been more critical than deep-rooted plants in the proliferation of muddy floodplains.

Item Type:Article
Related URLs:
URLURL TypeDescription Materials
Zeichner, Sarah S.0000-0001-8897-7657
Nghiem, Justin0000-0003-2772-9945
Lamb, Michael P.0000-0002-5701-0504
Takashima, Nina0000-0002-0349-5657
de Leeuw, Jan0000-0002-2005-4351
Ganti, Vamsi0000-0003-2165-6052
Fischer, Woodward W.0000-0002-8836-3054
Additional Information:© 2021 American Association for the Advancement of Science. This is an article distributed under the terms of the Science Journals Default License. Received 27 May 2020; accepted 21 December 2020. We thank T. Ulizio and M. Douglas for help with the experiments and valuable input. This work was made possible with support from the Caltech Discovery Fund (W.W.F. and M.P.L.), David and Lucile Packard Foundation (W.W.F.), American Chemical Society Petroleum Research Fund (W.W.F.), National Science Foundation Graduate Research Fellowship Program (S.S.Z.), and Troy Tech High School Program (N.T.). Author contributions: Methodology, Formal analysis, Software, Writing, Visualization: S.S.Z.; Software, Formal analysis, Writing, Visualization: J.N.; Conceptualization, Supervision, Funding acquisition: M.P.L.; Methodology, Writing – review & editing: J.d.L.; Validation, Data curation: N.T.; Formal analysis, Writing – review & editing: V.G.; Conceptualization, Supervision, Funding acquisition: W.W.F. We have no competing interests. Data and materials availability: All data are available in the main text or the supplementary materials. All code for image processing, statistical analyses, and the 1D sedimentation model is available at Zenodo (34).
Funding AgencyGrant Number
Caltech Discovery FundUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
American Chemical Society Petroleum Research FundUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Troy Tech High SchoolUNSPECIFIED
Issue or Number:6528
Record Number:CaltechAUTHORS:20210128-153836066
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Official Citation:Early plant organics increased global terrestrial mud deposition through enhanced flocculation. Sarah S. Zeichner, Justin Nghiem, Michael P. Lamb, Nina Takashima, Jan de Leeuw, Vamsi Ganti and Woodward W. Fischer. Science 371 (6528), 526-529; DOI: 10.1126/science.abd0379
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107797
Deposited By: Tony Diaz
Deposited On:29 Jan 2021 00:03
Last Modified:29 Jan 2021 00:03

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