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Research Interests:

My research interests are interdisciplinary and center on the late Quaternary paleoecology and paleoclimatology. Im interested in using multiple proxy data in studying dynamics of vegetation, climate, hydrology and carbon cycle and their connections. I have used multiple paleoecological records (pollen, conifer stomata and plant macrofossils) derived from lake and wetland sediments to reconstruct past flora and vegetation changes and to discuss environmental influences on dynamics/succession of upland and wetland vegetation. Reconstructed change in vegetation from these paleoecological records together with independent proxies on climate from oxygen isotopes and on soil/ landscape development from elemental geochemistry provide valuable data in discussing past ecosystem processes related to climate-soil-vegetation interactions.

Im also interested in paleoclimatic and paleohydrologic applications of stable-isotope and elemental geochemistry techniques. I have used these geochemical records from lacustrine carbonates (bulk marl, mollusc and ostracode shells) in investigating deglacial climate oscillations, mid-Holocene droughts and late Holocene wet-dry climate cycles. I have also involved in a project of using present-day lake water samples to calibrate isotopic and geochemical paleo-records. Over the last few years, I have worked on Holocene paleoclimate variations and associated peat carbon accumulation dynamics in continental peatlands using high-resolution 14C dating and paleoecological records. This line of research also involves modelling long-term peatland dynamics, especially for continental peatlands in western Canada. The long-term goal of my research program is to further integrate the multidisciplinary data in understanding earth system processes and in solving paleoecologic, paleoclimatic and paleohydrologic problems and to link modern processes to the record of environmental changes.

Recent and ongoing projects:

Collaborative Research: Identifying Hydroclimatic Regimes of Carbon Stability in Northern Peatlands - Holocene Data Analysis and Process-based Modeling. National Science Foundation Carbon and Water in the Earth System Program. Principal Investigator (PI): Yu, with PIs: Frolking (University of New Hampshire Lead PI) and MacDonald (UCLA). $543,105 to Lehigh University. 10/1/2006 - 9/30/2010.


Understanding Holocene Climate Variability in the Northeast: Insights from Multiple Sedimentary Proxy Records. The Petroleum Research Fund - American Chemical Society (Type AC). Principal Investigator: Yu. $80,000 for two years from 6/2005 to 8/2007.


Collaborative Research: Pilot Study for Testing Potential of Paired Lakes on the NE Tibetan Plateau for Multidisciplinary Study of Interaction Between Hydrochemical Evolution and Environmental Change. National Science Foundation Geobiology and Environmental Geochemistry/Global Change Programs. PIs: Z.C. Yu (Lehigh University Lead PI) and E. Ito (University of Minnesota). $48,835 to Lehigh University for 9/2005-8/2007.


Environmental Changes and Strategy in Northwest China. Chinese National Natural Science Foundation (Chinese NSF) National Outstanding Scholar Program, Principal Investigator: Yu (with collaborator F.H. Chen at Lanzhou University). 400,000 Yuan (~$50,000) for three years from 1/2006-12/2008.


Carbon Accumulation in the Fens of Boreal, Western Canada. National Science Foundation Integrated Carbon Cycle Program. Co-PI with K. Wieder (Villanova University Lead PI) and D. Vitt (Southern Illinois University at Carbondale). $138,199 to Lehigh University from 10/2002 to 9/2006.


Planning a Russian-American Peatland Research Program: A Coordinated Approach. National Science Foundation International Plan and Workshops Program, $34,091 for 08/05-08/06. Co-PIs: D.H. Vitt, M. Turetsky, M. Vile, Z.C. Yu, and R.K. Wieder. Awarded to Southern Illinois University, Carbondale.


In Search of Stable Isotopic Records of Deglacial Climate Oscillations in Mid-Atlantic Region. The Petroleum Research Fund - American Chemical Society. Principal investigator: Yu. $35,000 for 9/2002 - 8/2004 (extended to 8/2005).

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