Hodgskiss Malcolm S. W.

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Hodgskiss
First Name
Malcolm S. W.
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0000-0001-8859-2765

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  • Article
    A productivity collapse to end earth's great oxidation
    (National Academy of Sciences, 2019-08-27) Hodgskiss, Malcolm S. W. ; Crockford, Peter W. ; Peng, Yongbo ; Wing, Boswell A. ; Horner, Tristan J.
    It has been hypothesized that the overall size of—or efficiency of carbon export from—the biosphere decreased at the end of the Great Oxidation Event (GOE) (ca. 2,400 to 2,050 Ma). However, the timing, tempo, and trigger for this decrease remain poorly constrained. Here we test this hypothesis by studying the isotope geochemistry of sulfate minerals from the Belcher Group, in subarctic Canada. Using insights from sulfur and barium isotope measurements, combined with radiometric ages from bracketing strata, we infer that the sulfate minerals studied here record ambient sulfate in the immediate aftermath of the GOE (ca. 2,018 Ma). These sulfate minerals captured negative triple-oxygen isotope anomalies as low as ∼ −0.8‰. Such negative values occurring shortly after the GOE require a rapid reduction in primary productivity of >80%, although even larger reductions are plausible. Given that these data imply a collapse in primary productivity rather than export efficiency, the trigger for this shift in the Earth system must reflect a change in the availability of nutrients, such as phosphorus. Cumulatively, these data highlight that Earth’s GOE is a tale of feast and famine: A geologically unprecedented reduction in the size of the biosphere occurred across the end-GOE transition.
  • Article
    The Sedimentary Geochemistry and Paleoenvironments Project
    (Wiley, 2021-07-05) Farrell, Úna C. ; Samawi, Rifaat ; Anjanappa, Savitha ; Klykov, Roman ; Adeboye, Oyeleye O. ; Agic, Heda ; Ahm, Anne-Sofie C. ; Boag, Thomas H. ; Bowyer, Fred ; Brocks, Jochen J. ; Brunoir, Tessa N. ; Canfield, Donald E. ; Chen, Xiaoyan ; Cheng, Meng ; Clarkson, Matthew O. ; Cole, Devon B. ; Cordie, David R. ; Crockford, Peter W. ; Cui, Huan ; Dahl, Tais W. ; Mouro, Lucas D. ; Dewing, Keith ; Dornbos, Stephen Q. ; Drabon, Nadja ; Dumoulin, Julie A. ; Emmings, Joseph F. ; Endriga, Cecilia R. ; Fraser, Tiffani A. ; Gaines, Robert R. ; Gaschnig, Richard M. ; Gibson, Timothy M. ; Gilleaudeau, Geoffrey J. ; Gill, Benjamin C. ; Goldberg, Karin ; Guilbaud, Romain ; Halverson, Galen P. ; Hammarlund, Emma U. ; Hantsoo, Kalev G. ; Henderson, Miles A. ; Hodgskiss, Malcolm S. W. ; Horner, Tristan J. ; Husson, Jon M. ; Johnson, Benjamin ; Kabanov, Pavel ; Keller, C. Brenhin ; Kimmig, Julien ; Kipp, Michael A. ; Knoll, Andrew H. ; Kreitsmann, Timmu ; Kunzmann, Marcus ; Kurzweil, Florian ; LeRoy, Matthew A. ; Li, Chao ; Lipp, Alex G. ; Loydell, David K. ; Lu, Xinze ; Macdonald, Francis A. ; Magnall, Joseph M. ; Mänd, Kaarel ; Mehra, Akshay ; Melchin, Michael J. ; Miller, Austin J. ; Mills, N. Tanner ; Mwinde, Chiza N. ; O'Connell, Brennan ; Och, Lawrence M. ; Ossa Ossa, Frantz ; Pagès, Anais ; Paiste, Kärt ; Partin, Camille A. ; Peters, Shanan E. ; Petrov, Peter ; Playter, Tiffany L. ; Plaza-Torres, Stephanie ; Porter, Susannah M. ; Poulton, Simon W. ; Pruss, Sara ; Richoz, Sylvain ; Ritzer, Samantha R. ; Rooney, Alan D. ; Sahoo, Swapan K. ; Schoepfer, Shane D. ; Sclafani, Judith A. ; Shen, Yanan ; Shorttle, Oliver ; Slotznick, Sarah P. ; Smith, Emily F. ; Spinks, Sam ; Stockey, Richard G. ; Strauss, Justin V. ; Stüeken, Eva E. ; Tecklenburg, Sabrina ; Thomson, Danielle ; Tosca, Nicholas J. ; Uhlein, Gabriel J. ; Vizcaíno, Maoli N. ; Wang, Huajian ; White, Tristan ; Wilby, Philip R. ; Woltz, Christina R. ; Wood, Rachel A. ; Xiang, Lei ; Yurchenko, Inessa A. ; Zhang, Tianran ; Planavsky, Noah J. ; Lau, Kimberly V. ; Johnston, David T. ; Sperling, Erik A.
    Geobiology explores how Earth's system has changed over the course of geologic history and how living organisms on this planet are impacted by or are indeed causing these changes. For decades, geologists, paleontologists, and geochemists have generated data to investigate these topics. Foundational efforts in sedimentary geochemistry utilized spreadsheets for data storage and analysis, suitable for several thousand samples, but not practical or scalable for larger, more complex datasets. As results have accumulated, researchers have increasingly gravitated toward larger compilations and statistical tools. New data frameworks have become necessary to handle larger sample sets and encourage more sophisticated or even standardized statistical analyses. In this paper, we describe the Sedimentary Geochemistry and Paleoenvironments Project (SGP; Figure 1), which is an open, community-oriented, database-driven research consortium. The goals of SGP are to (1) create a relational database tailored to the needs of the deep-time (millions to billions of years) sedimentary geochemical research community, including assembling and curating published and associated unpublished data; (2) create a website where data can be retrieved in a flexible way; and (3) build a collaborative consortium where researchers are incentivized to contribute data by giving them priority access and the opportunity to work on exciting questions in group papers. Finally, and more idealistically, the goal was to establish a culture of modern data management and data analysis in sedimentary geochemistry. Relative to many other fields, the main emphasis in our field has been on instrument measurement of sedimentary geochemical data rather than data analysis (compared with fields like ecology, for instance, where the post-experiment ANOVA (analysis of variance) is customary). Thus, the longer-term goal was to build a collaborative environment where geobiologists and geologists can work and learn together to assess changes in geochemical signatures through Earth history.