Research

Current Research Projects: 

(1) Volcanism, Weathering, and Ocean Chemistry on the Eve of the Great Ordovician Biodiversification Event

The early Paleozoic witnessed two of the most profound evolutionary milestones in Earth history: The ‘Cambrian Explosion’ and the subsequent ‘Great Ordovician Biodiversification Event’ (GOBE), which were separated by 40-50 million years. The former was characterized by innovation of a range of new body plans and establishment of almost all of the extant phyla. The GOBE, by contrast, saw the emergence of few higher taxa but witnessed a three-fold increase in species-level diversity. Although faunal trends are well known, the environmental trigger of the GOBE is less well understood. This study seeks to constrain the contributions from volcanic activities, weathering, and marine redox conditions at the dawn of the GOBE by using multiple geochemical tools that will allow me to better understand the associated feedbacks within the Ordovician Earth system that consequently drove the evolutionary landmark in the early Paleozoic.

(2) Co-evolving Redox and Ecosystem Structures in the Early Oceans: Probing the Earliest Environmental Controls and Consequences of Complex Life

The mid-Proterozoic, bracketed by two dramatic steps in the oxygenation of Earth’s atmosphere-ocean system (the Great Oxygenation Event and the Neoproterozoic Oxygenation Event), is marked by remarkable long-term carbon cycle stability associated with seemingly equivalent stability in climate, surface environments, and biology. This period of relatively static life and environments is widely known as the ‘Boring Billion’. Despite their early rise, eukaryotic organisms were not abundant throughout the Mesoproterozoic and did not constitute an ecologically significant lineage until the middle Neoproterozoic. Multiple lines of evidence suggest that the oxygen levels were generally low in the atmosphere during the Mesoproterozoic, and the oceans were dominated persistently anoxic, iron-rich (ferruginous) conditions with very shallow chemoclines. These muted oxic conditions may have played a key role in the evolutionary and ecological stasis of eukaryotic life during the middle chapter of Earth history. Nevertheless, a growing body of evidence suggests dynamic redox conditions in Earth surface environments, characterized by multiple possible pulses of atmospheric oxygenation. This study aims to test the dynamic redox conditions in the mid-Proterozoic Earth surface system, and to shed light on the ecological role of eukaryotes within the microbial communities through biomarker records. Ultimately, these comprehensive approaches will enable me to assess the role of oxygen in the rise and evolution of complex life.

(3) Dynamic Evolution of Marine Productivity, Redox, and Biogeochemical Cycling Linked to Waxing and Waning Cryogenian Glaciation

The Cryogenian Period (~720－635Ma) of the Neoproterozoic was characterized by two episodes of Snowball Earth events (Sturtian and Marinoan glaciations), which were potentially tied to the rise of algae and diversification of eukaryotes that culminated with the emergence of animals. This study will focus on a unique black shale sequence (Datangpo Formation) deposited in a restricted rift basin (Nanhua Basin, South China) during the non-glacial period between Snowball Earths, to provide insights into the dynamic redox conditions of the local depositional environments which were primarily controlled by the wax and wane of the profound glaciations associated with large-scale sea level changes. This study will inform better understanding toward the intrinsic relationships among glaciations, eustatic changes, nutrient availability, primary production, and redox state within the Earth system over this critical geological transition.

FORMER Research Projects: 

Before I pursued my PhD study at UC-Riverside, I completed my undergraduate study at China University of Geosciences (Wuhan), where I undertook multiple projects and developed my strong interest in geobiology. I mainly focused on the co-evolution of life, climates and environments over the Permian-Triassic transition, which witnessed the greatest biocrisis during the Phanerozoic and subsequent delayed recovery. My research involved stratigraphy, paleobiology and sedimentology. The major projects I led are: (1) Permian–Triassic evolution of the Bivalvia: Extinction–recovery patterns linked to ecologic and taxonomic selectivity; (2) Microbially induced sedimentary structures from the Early Triassic terrestrial deposits in Yiyang county, Henan Province, North China.