@article{3b130a6fea98482e9e2853aaf2f36a70,
title = "Multiscale approach reveals that Cloudina aggregates are detritus and not in situ reef constructions",
abstract = "The earliest metazoans capable of biomineralization appeared during the late Ediacaran Period (635–541 Ma) in strata associated with shallow water microbial reefs. It has been suggested that some Ediacaran microbial reefs were dominated (and possibly built) by an abundant and globally distributed tubular organism known as Cloudina. If true, this interpretation implies that metazoan framework reef building—a complex behavior that is responsible for some of the largest bioconstructions and most diverse environments in modern oceans—emerged much earlier than previously thought. Here, we present 3D reconstructions of Cloudina populations, produced using an automated serial grinding and imaging system coupled with a recently developed neural network image classifier. Our reconstructions show that Cloudina aggregates are composed of transported remains while detailed field observations demonstrate that the studied reef outcrops contain only detrital Cloudina buildups, suggesting that Cloudina played a minor role in Ediacaran reef systems. These techniques have wide applicability to problems that require 3D reconstructions where physical separation is impossible and a lack of density contrast precludes tomographic imaging techniques.",
keywords = "Biomineralization, Early life, Ediacaran, Reefs, Three-dimensional reconstructions",
author = "Akshay Mehra and Maloof, {Adam C.}",
note = "Funding Information: ACKNOWLEDGMENTS. We thank C. Husselmann for granting us access to Driedoornvlakte Farm, G. and L. Fourie for allowing us to work in Zebra River Farm, and the Curtis family for opening up Donkergange Farm. M. Laflamme and R. Wood provided helpful discussions while in Namibia. G. Schneider at the Geological Survey of Namibia granted us permits for working in Namibia. J. Eiseb of the Geological Survey of Namibia assisted us with the export permitting process. J. Grotzinger let us use his locker at the Geological Survey of Namibia. We thank BC Parks for granting us a permit to conduct fieldwork on Salient Mountain and Matt Morison at Yellowhead Helicopters for logistical support. All of Situ Studio, but especially B. Samuels, were instrumental in the development of GIRI. A. Spatzier developed the initial routines and operational procedures for GIRI. K. Kellerson at Millennium Machinery gave us useful advice about machine programming and grinding processes. A. Tasistro Hart, R. Bartolucci, W. Van Cleve, and C. Gray provided assistance in the field. S. Gwizd, A. Hager, and D. Okhai helped prepare and run samples for stable isotope analysis. B. Getraer assisted with measuring and electronics fabrication. J. Irving first suggested the use of neural networks for fossil segmentation. This paper benefited from feedback by M. Eddy, B. Schoene, S. Porter, and A. Knoll. We thank the editor and two anonymous reviewers for their thoughtful feedback. This work was supported by NSF Earth Sciences Grant 1028768 to A. Maloof and by funding from the Princeton Tuttle Invertebrate Fund. Funding Information: We thank C. Husselmann for granting us access to Driedoornvlakte Farm, G. and L. Fourie for allowing us to work in Zebra River Farm, and the Curtis family for opening up Donkergange Farm. M. Laflamme and R. Wood provided helpful discussions while in Namibia. G. Schneider at the Geological Survey of Namibia granted us permits for working in Namibia. J. Eiseb of the Geological Survey of Namibia assisted us with the export permitting process. J. Grotzinger let us use his locker at the Geological Survey of Namibia. We thank BC Parks for granting us a permit to conduct fieldwork on Salient Mountain and Matt Morison at Yel-lowhead Helicopters for logistical support. All of Situ Studio, but especially B. Samuels, were instrumental in the development of GIRI. A. Spatzier developed the initial routines and operational procedures for GIRI. K. Kellerson at Millennium Machinery gave us useful advice about machine programming and grinding processes. A. Tasistro Hart, R. Bartolucci, W. Van Cleve, and C. Gray provided assistance in the field. S. Gwizd, A. Hager, and D. Okhai helped prepare and run samples for stable isotope analysis. B. Getraer assisted with measuring and electronics fabrication. J. Irving first suggested the use of neural networks for fossil segmentation. This paper benefited from feedback by M. Eddy, B. Schoene, S. Porter, and A. Knoll. We thank the editor and two anonymous reviewers for their thoughtful feedback. This work was supported by NSF Earth Sciences Grant 1028768 to A. Maloof and by funding from the Princeton Tuttle Invertebrate Fund. Publisher Copyright: {\textcopyright} 2018 National Academy of Sciences. All Rights Reserved.",
year = "2018",
doi = "10.1073/pnas.1719911115",
language = "English (US)",
volume = "115",
pages = "E2519--E2527",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "11",
}