Andrew H. Knoll


Geobiology, paleobotany, environments on Mars.
Post Docs:

David Johnston


As an isotope / experimental geobiologist, my primary interest is in better understanding the relationship between microorganisms and Earth surface evolution. This ranges from tracking the onset or environmental expression of different metabolic processes to following atmospheric / oceanic oxidation and evolution. My work blends an understanding of stable isotope systems (primarily sulfur [ 32 S, 33 S, 34 S, 36 S] and oxygen [ 16 O, 17 O, 18 O]) with modern microbial ecology and geologic terrains.

In collaboration with Peter Girguis and Andy Knoll and through the Microbial Sciences Initiative (MSI) program, I am investigating new means of constraining the evolution of the Precambrian biosphere and changes in ocean chemistry. In the lab, the goal is to quantitatively track the relationship between environmental conditions and microbial populations. Specifically, we are interested in using a novel bioreactor design to better fingerprint the microbial response (using isotopic and quantitative molecular techniques) to changes in seawater sulfate concentrations. Field based studies are employing proven techniques, as well as developing new proxies for uncovering the character of Proterozoic marine sediments. These include, but are not limited to whole rock isotopic and elemental investigations (C, S, O, Fe…), extraction of trace phases (such as carbonate associated sulfate), and the mineralogical and isotopic study of black chert.


Graduate Students:

Jon Wilson


I am interested in reconstructing the physiology of extinct plants. Terrestrial plants preserve a record of their development, structure, and physiology in the chemistry and morphology of their cell walls, and my research uses fluid dynamics modeling, geochemical analysis, and comparative anatomy to understand water transport rates in Paleozoic and Mesozoic plants that have no close extant relatives.  I hope that a more complete knowledge of extinct plant function will shed light on paleoenvironmental and phylogenetic interpretation, as well as the evolutionary history of seed plants.
Leaf physiology and function

Phoebe Cohen

I am interested in the roles that biological and environmental factors played in the events leading up to the Cambrian radiation. I am approaching this by investigating Neoproterozoic eukaryotic evolution, specifically looking at the evolutionary history and biological affinity of organic-walled microfossils known as acritarchs. Many gaps remain in our understanding of acritarch evolution through time, especially the potential effects of the Sturtian and Marinoan glaciations. However, these questions cannot be fully answered until we have a better grasp of acritarchs' biological affinities. I am approaching these questions with a combination of field work and analyses of possible modern acritarch analogs.

Ben Kotrc


Ben hails from Vienna, Austria. He has an undergraduate degree in geology from Imperial College, London, and a master's degree in paleobiology from the University of Bristol. He has worked on the Paleocene/Eocene Thermal Maximum in the North Sea, during a brief stint working for Shell, and on the Cenozoic evolution of size and silica use in Radiolaria while in Bristol. He carried out field work for his undergraduate thesis in the Precambrian Mozambique Orogenic Belt in the Samburu District, Kenya. His research interests are broad-ranging and include, but are not limited to, the interaction and coevolution of the biological and geological earth systems over time, evolution and biogeochemical cycles, macroecology, complexity, computer modeling and the evolutionary history of marine plankton.
Visiting Students  
Renata Hidalgo

Renata Hidalgo is a Research Assistant in the Paleobotany Lab. After graduating with a biology degree from Universidade Estadual Paulista, Brazil, Renata taught Biology and Chemistry at a High School for several years. She was interested in
origin of life and then graduated with a Masters of Science at Universidade de São Paulo in Brazil. Since then, her studies has focused on Precambrian microfossils. Recent research projects include stratigraphy and paleontology in the three
areas in Brazil: Couto Magalhães Formation (Pará State), Araras Group (Mato Grosso State) and Corumbá Group (Mato Grosso do Sul Sate).

Administration: Diane Sheridan
Collaborators at Harvard: Charles Marshall Analytical paleontology
Ann Pearson Biogeochemistry
Paul Hoffman Earth history
Missy Holbrook Plant physiology

Knoll Group Alumni

Graduate Students

Julian Green (University of South Carolina)

Stephen Grant

Nicholas Butterfield (University of Cambridge)

Loren Smith

Nan Arens (Hobart and William Smith College)

Linda Kah (University of Tennessee)

Shuhai Xiao (Virginia Tech)

Susannah Porter (UC Santa Barbara)

Kevin Boyce (University of Chicago)

Jon Payne (Stanford University)

Woodrow Fischer (Caltech)

Robin Kodner

Postdoctoral Fellows

Roger Buick (University of Washington)

Sarah Damassa (Consulting Palynologist)

Vladimir Sergeev (Geological Institute, Russian Academy of Sciences)

Jay Kaufman (University of Maryland)

Julie Bartley (Western Georgia University)

Bruce Lieberman (University of Kansas)

Nora Noffke (Old Dominion University)

Emmanuelle Javaux (Liege University, Belgum)

Jochen Brocks (Australian National University)

Yanan Shen (University of Montreal)

Matt Hurtgen (Northwestern University)

Sara Pruss (Smith College)

Long Term Researchers

Anne Raymond (Texas A&M University – Radcliffe fellow)

Connie Soja (Colgate University – Radcliffe Fellow)

Dong Xiping (Peking University, PR China)

Akiko Tomitani ( Institute for Research on Earth Evolution, Japan)

Tanja Bosak (MIT -- MSI Fellow)

David Fernandez Remolar (Spanish Center for Astrobiology)

Richard Bambach (Virginia Tech, emeritus)