Postdoctoral Associate

phone (608) 469 7590

Department of Earth, Atmospheric and Planetary Sciences
Massachusetts Institute of Technology
E54-1025, 77 Mass Ave
Cambridge, MA 02139



2016-present –Agouron Postdoctoral Associate, Department of Earth, Atmospheric and Planetary Sciences, MIT
2009-2016 – Ph.D., Department of Earth and Planetary Sciences, University of California-Davis
2009-2012 – M.S., Geology Department, University of California-Davis
2004-2008 – B.A., Geology Department, Carleton College

Tyler works in modern microbial ecosystems and their ancient sedimentary record to explore the history of life on Earth. His research combines field observations with detailed sedimentary and geochemical analyses to assess records of early animal and microbial activity preserved in carbonates. Tyler received his PhD from the University of California, Davis Department of Earth and Planetary Sciences, where his work focused on microbial communities of ice covered lakes in Antarctica. He is currently an Agouron Postdoctoral Fellow in the Massachusetts Institute of Technology Department of Earth, Atmospheric and Planetary Sciences.


The expansion of complex multicellular life like animals marks a pivotal point in Earth history, with the origin of novel behaviors that transformed the evolutionary and biogeochemical landscape. Evidence for the first animals comes in the midst of the major climate perturbations of the Cryogenian (635-850 Ma), but the habitats that would have been available for these early animals are poorly defined.

Tyler works with Cryogenian sedimentary successions from Svalbard, where transitions between glacial Snowball Earth and interglacial conditions are preserved in mixed carbonate and siliciclastic sections. Within these varied depositional environments, he explores how changes in climate affect the habitats that would have been available for early animal evolution. This work combines sedimentary and petrographic observations with analysis of carbonate clumped isotopes, synchrotron-based characterization of Mn and Fe redox state, and biomarkers across Sturtian and Marinoan glacial deposits in Svalbard. By combining these data sets he constrains (a) diagenetic conditions that could have modified environmental signatures, (b) the range of physical environments and oxygenation of habitats available during glacial episodes and (c) the biological significance of the habitats.

Alongside this work in the Cryogenian, Tyler continues his research in modern Antarctic microbial mats. Such microbial ecosystems serve as a natural laboratory to test how information about depositional environments and biological activity can enter into the rock record.

Select Publications

Mackey, TJ, Sumner, DY, Hawes, I, Leidman, S, Andersen, DT, Jungblut, AD (2018) Stromatolite records of changing primary productivity in perennially ice-covered Lake Joyce, McMurdo Dry Valleys, Antarctica. Biogeochemistry. 137(1-2): 73-92 DOI:10.1007/s10533-017-0402-1

Mackey, TJ, Sumner, DY, Hawes, I, Jungblut, AD (2017) Morphological signatures of microbial activity across depositional microenvironments of Lake Vanda, Antarctica. Sedimentary Geology. 361: 82-92. DOI:10.1016/j.sedgeo.2017.09.013

Mackey, TJ, Sumner, DY, Hawes, I, Jungblut, AD, Lawrence, J, Leidman, S, Allen, B (2017) Increased mud deposition reduces stromatolite complexity. Geology, 45: 663-666. DOI:10.1130/G38890.1

Jungblut, AD, Hawes, I, Mackey, TJ, Krusor, M, Doran, P, Sumner, DY, Eisen, J, Hillman, C, Goroncy, A (2016) Microbial mat communities along an oxygen gradient in a perennially ice-covered Antarctic lake. Applied and Environmental Microbiology, 82(2): 620-630. DOI:10.1128/AEM.02699-15

Sumner, DY, Hawes, I, Mackey, TJ, Jungblut, AD, Doran, P (2015) Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases. Geology, 43: 887-890. DOI:10.1130/G36966.1

Mackey, TJ, Sumner, DY, Hawes, I, Jungblut, AD, Andersen, DT, (2015) Growth of modern branched columnar stromatolites in Lake Joyce, Antarctica. Geobiology, 13: 373-390. DOI:10.1111/gbi.12138

Hawes, I, Sumner, DY, Andersen, DT, and Mackey, TJ (2011) Legacies of recent environmental change in the benthic communities of Lake Joyce, a perennially ice-covered Antarctic lake. Geobiology, 9: 394-410. DOI: 10.1111/j.1472-4669.2011.00289.x