Friday, October 31, 2014

New Geobiology Publication

Check out this new publication in Nature Geosciences by Mariotti, G., Pruss, S. B., Perron, J. T., & Bosak, T.

Microbial shaping of sedimentary wrinkle structures

Abstract: Wrinkle structures on sandy bed surfaces were present in some of the earliest sedimentary environments, but are rare in modern environments. These enigmatic millimetre- to centimetre-scale ridges or pits are particularly common in sediments that harbour trace fossils and imprints of early animals, and appeared in the aftermath of some large mass extinctions. Wrinkle structures have been interpreted as possible remnants of microbial mats, but the formation mechanism and associated palaeoenvironmental and palaeoecological implications of these structures remain debated. Here we show that microbial aggregates can form wrinkle structures on a bed of bare sand in wave tank experiments. Waves with a small orbital amplitude at the bed surface do not move sand grains directly. However, they move millimetre-size, light microbial fragments and thereby produce linear sand ridges and rounded scour pits at the wavelengths observed in nature within hours. We conclude that wrinkle structures are morphological biosignatures that form at the sediment–water interface in wave-dominated environments, and not beneath microbial mats as previously thought. During early animal evolution, grazing by eukaryotic organisms may have temporarily increased the abundance of microbial fragments and thus the production of wrinkle structures.

Tenure Track Job - Geobiology (Dartmouth College)

The Department of Earth Sciences at Dartmouth College invites applications for a junior rank tenure-track position in the general areas of biogeochemistry and geobiology. We especially welcome applications from candidates with research interests that include microbially-mediated biogeochemical interactions in processes of mineralization, weathering, and sequestration of contaminants; hydrocarbon formation and degradation; biogeochemical cycling in fluvial and/or cold environments, including river-channel, floodplain, and lacustrine ecosystem response to environmental change. 

Find out more here:

Tenure Track Job - Paleontology (University of Michigan)

The Museum of Paleontology and the Department of Earth and Environmental Sciences at the
University of Michigan are searching for a tenure-track faculty candidate in the field of
Paleontology. This is a university year appointment with an expected start date of September 1,

Find out more here:

Thursday, October 30, 2014


Hi Everyone! We are working on a new Website/Blog for the GSA Geobiology and Geomicrobiology division. Come to this site for news about the division, recent papers, member profiles, job listings (Postdoc and Tenure track), and student opportunities! In case you aren't familiar with us, here's our purpose statement:

The purpose of the Division is to bring together scientists working at the interface of biology and geology; to encompass the integration of these disciplines through time and across space; to simultaneously promote both the broad scope and detailed disciplinary work demanded of rigorous interdisciplinary research; to nurture this emerging spectrum of fields by active encouragement and mentoring of students; and to advise and assist the officers and committees of GSA in matters related to geobiology and geomicrobiology. Fields currently within this Division include: biogeochemistry, biomineralogy, geochemical ecology, paleontology, micropaleontology, origins of life and co-evolution of planets and life, paleobiology and paleoecology, molecular paleontology and ecology, systems modeling and informatics, and astrobiology.