Zach studies two of the major transitions in the history of life as part of the Knoll Group: the origins of replicating molecules and the origins of the eukaryotic cell. For his PhD project, he discovered two new sources of microfossils in the 1.4 billion year old Belt Supergroup of Montana. The assemblages include unique specimens of Tappania plana, one of the earliest examples of complex eukaryotes and the first such fossils reported from Laurentia. The quality of preservation, diversity of the assemblages and the accessibility of the units opens new avenues into exploring the morphology and ecology of some of Earth’s oldest eukaryotes. Zach continues to use these and other fossils for his postdoctoral project, looking for taxon-specific carbon isotope values and ultrastructural clues as to the affinity or metabolism of these organisms.
Zach also studies geologic settings that could have promoted the synthesis of complex organic compounds on the early Earth, with a focus on conditions capable of driving prebiotic oligomer synthesis reactions. Using radioactive heavy mineral placer beaches as a conceptual model, his work has turned to the production of reactive phosphorus, mirror symmetry-breaking radiation and non-enzymatic oligomer synthesis arising from neutron moderation-governed temperature fluctuations