Chaohui Zhang

Dr. Zhaohui Zhang is a Qiushi Professor at Zhejiang University, a former director of the Institute of Marine Chemistry and Environment at Zhejiang University.

Dr. Zhang was graduated from Nanjing University with a B.S. degree in 1990 and from the Institute of Geochemistry, Chinese Academy of Sciences with a M.S. degree in 1993. Then he worked as a research assistant and research associate in the Institute of Geochemistry, Chinese Academy of Sciences .

Dr. Zhang obtained his Ph.D. from Dartmouth College, the smallest school in the Ivy League in March 2003. He was awarded a Comer Postdoctoral Fellowship and worked in the Chemcial Oceanography group at the Massachusetts Institute of Technology (MIT) from April, 2003 to December, 2005. He spent half year working at the Woods Hole Oceanographic Institute (WHOI) during this period. He worked as a senior research associate at University of Massachusetts Amherst from 2006 till 2008. During this period he spent half year as a visiting scholar at the School of Oceanography, University of Washington. Dr. Zhang served as a professor at Nanjing University from 2009 to 2015, before he joined the faculty in Ocean College at Zhejiang University in 2016.

His interests are biomarkers preserved in water columns, and sediments (ocean, lake and loess)--their molecular structures and compound-specific carbon and hydrogen isotopes in order to better understand paleovegetation and paleoenvironment. He is interested in hydrogen isotope fractionation during algal growth and their responses to environmental factors such as temperature, nutrient limited growth rates, etc, GDGT distributions in water columns, biomarkers as paleoenvironmetnt and paleocliamte indicators, and organic chemical process in the water columns in oceans.

Education

Ph.D. (2003) Dartmouth College, Hanover, NH, USA

M.S. (1993) Institute of Geochemistry at Chinese Academy of Science, Guiyang, China

B. S. (1990) Nanjing University, Nanjing, China

Employment History

Professor, Ocean College, Zhejiang University, 2015-present

Professor, School of Earth Sciences and Engineering, Nanjing University, 2008–2015

Senior Research Associate, University of Massachusetts Amherst, 2006–2008

Comer Postdoctoral Fellow, Massachusetts Institute of Technology, 2003–2005

Research Assistant, Institute of Geochemistry, Chinese Academy of Sciences, 1993-1996

Grants from the National Science Foundation of China

1. The evolution of the Indian water flux into the Red Sea and its environmental impacts during the Holocene: Biomarker-based reconstruction (NSF 41673098, 2017-2020)

2. Biomarkers and their compound-specific carbon and hydrogen isotope study of sulfate reducing bacteria and archaea in hot springs   (NSF 41473069, 2015-2018)

3.  Biomarkers and their compound-specific carbon and hydrogen isotope study of sulfate reducing bateria and archaea in hot springs   (NSF 41473069, 2015-2018)

4. Litter decomposition mechanism: a prospective from compound-specific carbon isotope study  (NSF 41273086, 2013-2016)

5. The study of applicability of GDGTs-based paleoenvironmental proxies in stratified lakes and high-latitude lakes   (NSF 41173080, 2012-2015)

6. Compound-specific radiocarbon dating of biomarker in the loess/paleosol deposits on the Chinese Loess Plateau    (NSF 40973052, 2010-2012)

7. Reconstruction of paleomosoonal precipitation using compound-specific hydrogen isotope of algal biomarkers    (NSF 40873056, 2009-2011)

Key member, Innovation Research Group project of National Science Foundation

     1.  Surfacial Geochemistry and environmental shifts  (NSF 41021002; 2011.01-2013.12）

     2.  Surfacial Geochemistry and environmental shifts（NSF 41321062; 2014.01-2016.12)

My research interests have been on organic geochemistry and using biomarker distribution and their compound-specific hydrogen and carbon isotope ratios for reconstructing temperature, precipitation and vegetation, which enable us to understand climate change and related ecosystem responses in the past.

1. Hydrogen isotope fractionation in algal lipids

I have been keen on to what extent the algal lipids record water D/H ratios. I conducted a series of algal cultures under controlled conditions at Woods Hole Oceanographic Institution, involving five species from different families and grown under different temperatures. I performed intensive lab work on separating different classes of algal lipids and measured their compound-specific hydrogen isotope ratios on GC-IRMS at MIT. In 2006 when I was visiting University of Washing for half year, I further supplemented this study with the effect of nutrient limitation and growth rate by studying the D/H ratio difference in algal lipids grown under nutrient-deplete and nutrient-replete conditions.

2. Reconstruction of paleoprecipitation with compound-specific hydrogen isotope ratios

The largest perturbation to global climate on an inter-annual time scale is the El-Nino-Southern Oscillation (ENSO). El Niño significantly changes the global precipitation patterns, causing drought in normally rain-abundant locations such as Indonesia and torrential rains in desert regions such as Galápagos Islands of Ecuador. Will El Niños become more intense and/or frequent in response to global warming? Such precipitation reconstruction used to be a formidable job because we did not have the right parameter (tool) as a rain gauge.

We chose an enclosed lake with a single source (rain) and sink (evaporation) of water, where the lake level and the D/H ratio of water are determined by the balance between precipitation and evaporation (P/E). Algae utilize dissolved CO₂, water and sunlight for photosynthesis. As hydrogen atoms are only sourced from water, we can assume the algal lipid D/H ratio would reflect that of water in which they grow. By measuring the dD of algal biomarker preserved in lake sediments, we might be able to reconstruct a profile of water level and precipitation variation.

3. Reconstruction of paleovegetation using compound-specific carbon isotope ratios

My ideas were to use the molecular biomarker approach to see how continental C₄ vs. C₃ vegetation changes might have responded to climate variations during the Last Glacial to the Holocene transition. One possibility was to employ the technique of analyzing the carbon isotope ratios of long-chain n-alkanes preserved in sediment deposits. Long-chain (C₂₇-C₃₅) n-alkanes with characteristic odd-over-even number predominance are mostly produced by land vascular plants. Their distributions make n-alkanes a good proxy for terrestrial plant input because these compounds are highly resistant to biochemical degradation and often survive sediment diagenesis. I chose the Chinese Loess Plateau as my main study site.

Growing-season temperature, precipitation and lower pCO₂ have all played a part in controlling C₄ vs. C₃ vegetation change in monsoonal China. The former two factors are tightly related with monsoonal variations during the LGM to the Holocene transition. During the LGM, strengthening winter monsoon/weakened summer monsoon resulted in decreasing temperatures but increasing aridity, while the amplitudes varied in the different regions. Our new n-alkane d¹³C data showed that the CLP witnessed a significant decrease in C₄ plant cover because of lower growing-season temperatures, despite lower pCO₂ and higher aridity. A growth-season temperature below a turnover point of about 14°C appears to be deleterious for C₄ vegetation. By contrast, in the Holocene, C₄ plant coverage increased on the CLP as growth-season temperatures rose.

4.  The applicability of TEX₈₆ in temperature reconstruction using GDGTs preserved in lake sediments

●   Zhaohui Zhang*,  Rienk H. Smittenberg and Raymond S. Bradley (2016) GDGT distribution in  a stratified lake and implications for the application of TEX₈₆ in paleoenvironmental reconstructions. Scientific Reports 6, 34465; doi: 10.1038/srep34465

●   Richard  J. Arculus, Osamu Ishizuka, Kara A. Bogus, Michael Gurnis, Rosemary  Hickey-Vargas, Mohammed H. Aljahdali, Alexandre N. Bandini-Maeder,  Andrew P. Barth, Philipp A. Brandl, Laureen Drab, Rodrigo do Monte  Guerra, Morihisa Hamada, Fuqing Jiang, Kyoko Kanayama, Sev Kender, Yuki  Kusano, He Li, Lorne C. Loudin, Marco Maffione, Kathleen M. Marsaglia,  Anders McCarthy, Sebastién Meffre, Antony Morris, Martin Neuhaus, Ivan  P. Savov, Clara Sena, Frank J. Tepley III, Cees van der Land, Gene M.  Yogodzinski and Zhaohui Zhang (2016) Reply to ‘unclear causes for subduction’. Nature Geoscience 9, 338-339

●   Arculus,  R.J., Ishizuka, O., Bogus, K., Aljahdali, M.H., Bandini-Maeder, A.N.,  Barth, A.P., Brandl, P.A., do Monte Guerra, R., Drab, L., Gurnis, M.C.,  Hamada, M., Hickey-Vargas, R.L., Jiang, F., Kanayama, K., Kender, S.,  Kusano, Y., Li, H., Loudin, L.C., Maffione, M., Marsaglia, K.M.,  McCarthy, A., Meffre, S., Morris, A., Neuhaus, M., Savov, I.P., Sena Da  Silva, C.A., Tepley, F.J., III, van der Land, C., Yogodzinski, G.M., and  Zhang, Z., 2015. Expedition 351 summary. In Arculus, R.J., Ishizuka, O., Bogus, K., and the Expedition 351 Scientists, Proceedings of the International Ocean Discovery Program, Expedition 351: Izu-Bonin-Mariana Arc Origins: College Station, TX (International Ocean Discovery Program). http://dx.doi.org/10.14379/iodp.proc.351.101.2015

●   Richard  J. Arculus, Osamu Ishizuka, Kara A. Bogus, Michael Gurnis, Rosemary  Hickey-Vargas, Mohammed H. Aljahdali, Alexandre N. Bandini-Maeder,  Andrew P. Barth, Philipp A. Brandl, Laureen Drab, Rodrigo do Monte  Guerra, Morihisa Hamada, Fuqing Jiang, Kyoko Kanayama, Sev Kender, Yuki  Kusano, He Li, Lorne C. Loudin, Marco Maffione, Kathleen M. Marsaglia,  Anders McCarthy, Sebastién Meffre, Antony Morris, Martin Neuhaus, Ivan  P. Savov, Clara Sena, Frank J. Tepley III, Cees van der Land, Gene M.  Yogodzinski and Zhaohui Zhang (2015) A record of spontaneous subduction initiation in the Izu-Bonin-Mariana arc. Nature Geoscience 8, 728-733

●  Weiming Gong and Zhaohui Zhang* (2015) Lipid biomarkers and organic matter   carbon isotopes in estuarine sediments as proxies for evaluating seawater intrusion. Estuarine, Coastal and Shelf Sciences 155, 38-46.

●  Zhaohui Zhang*,  Guillaume Leduc, and Julian P. Sachs (2014)  El Niño evolution  during the Holocene revealed by a biomarker rain gauge in the Galápagos  Islands. Earth and Planetary Science Letters 404, 424-434

●  Zhaohui Zhang*, Pierre Metzger and Julian P. Sachs (2014) Bound lipid biomarkes in sediments from El Junco Lake, Galápagos Islands. Organic Geochemistry 75, 122-128

●   Zhaohui Zhang*, Daniel, B. Nelson, and Julian P. Sachs (2014) Hydrogen isotope fractionation in algae: III. Theoretical interpretations. Organic Geochemistry 75, 1-7

●   Ji Shen, Xudong Wu, Zhaohui Zhang^*,  Weiming Gong, Tong He, Xiaomei Xu, Hailiang Dong (2013) Ti content in  Huguangyan maar lake sediment as a proxy for vegetation density and  erosion rate in the Holocene. Geophysical Research Letters 40, 1-7

●   Huayu  Lu, Shuangwen Yi, Zhengyu Liu, Joseph A. Mason, Dabang Jiang, Jun  Cheng, Thomas Stevens, Zhiwei Xu, Enlou Zhang, Liya Jin, Zhaohui Zhang,  Zhengtang Guo, Yi Wang, and Bette Otto-Bliesner (2013) Variation of  East Asian monsoon precipitation during the past 21 k.y. and potential  CO₂ forcing. Geology 41, 1023-1026

●   Zhaohui Zhang*,  Pierre Metzger and Julian P. Sachs (2013) Unprecedented long chain  1-chloroalkenes and 1-chloroalkanes in the Holocene sediments of Lake El  Junco, Galápagos Islands. Organic Geochemistry 57, 1-6

●   Xudong Wu, Zhaohui Zhang*,  Xiaomei Xu and Ji Shen (2012) Asian summer monsoonal variations during  the Holocene revealed by Huguangyan maar lake sediment record. Palaeogeography, Palaeoclimatology, Palaeoecology 323-325, 13-21

●   Zhaohui Zhang*, Pierre Metzger and Julian P. Sachs (2011) Co-occurrence  of long-chain diols, keto-ols, hydroxy acids and keto acids in recent  sediments of Lake El Junco, Galápagos Islands. Organic Geochemistry 42, 823-837

●   Nicholas L. Balascio, Zhaohui Zhang,  Raymond S. Bradley, Bianca Perren, Svein Olaf Dahl, Jostein Bakke  (2011) A multi-proxy approach to assessing isolation basin stratigraphy  from the Lofoten Islands, Norway. Quaternary Research 75, 288-300

●   Mark B. Bush, Paul A. Colinvaux, M. Steinitz-Kannan, J.T. Overpeck, J. Sachs, J. Cole, A. Collins, J. Conroy, A. Restrepo and Zhaohui Zhang (2010) Forty years of Paleoecology in the Galápagos. Galápagos Research 67, 55-61

●   Julian P. Sachs, Dirk Sachse, Rienk Smittenberg, Zhaohui Zhang, David S. Battisti, Stjepko Golubic (2009) Southward movement of the Pacific Convergence Zone AD 1400 to 1850. Nature Geoscience 2, 519-525

●   Zhaohui Zhang*,  Julian P. Sachs, and Adrian Marchetti (2009) Hydrogen isotope  fractionation in freshwater and marine algae: II. Temperature and  nitrogen limited growth rate effects. Organic Geochemistry 40, 428-439

●   Stefan  Schouten, Ellen C. Hopmans, Jaap van der Meer, Anchelique Mets, Edouard  Bard, Thomas S. Bianchi, Aaron Diefendorf, Marina Escala, Katharine H.  Freeman, Yoshihiro Furukawa, Carme Huguet, Anitra Ingalls, Guillemette  Ménot-Combes, Alexandra J. Nederbragt, Masahiro Oba, Ann Pearson, Emma  J. Pearson, Antoni Rosell-Melé, Philippe Schaeffer, Sunita R. Shah,  Timothy M. Shanahan, Richard W. Smith, Rienk Smittenberg, Helen M.  Talbot, Masao Uchida, Benjamin A.S. Van Mooy, Masanobu Yamamoto, Zhaohui Zhang,  Jaap S. Sinninghe Damsté (2009) An interlaboratory study of TEX86 and  BIT analysis using high performance liquid chromatography/mass  spectrometry. Geochemistry, Geophysics and Geosystems 10(3) doi:10.1029/2008GC002221

●   Zhaohui Zhang*, Pierre Metzger and Julian P. Sachs (2007) Biomarkers evidence for the co-occurrence of three races (A, B and L) of Botryococcus braunii in Lake El Junco, Galápagos. Organic Geochemistry 38, 1459-1478

●   Zhaohui Zhang* and Julian P. Sachs (2007) Hydrogen isotope fractionation in freshwater algae: I. Variations among lipids and species. Organic Geochemistry 38, 582-608

●   Julian P. Sachs, Katharina Pahnke, Rienk H. Smittenberg and Zhaohui Zhang (2007) Biomarker indicators of past climate. In Elias, S.A. (Ed.). Encyclopedia of Quaternary Science. Vol.2. Elsevier, pp. 1627-1633

●   Zhaohui Zhang,  Meixun Zhao, Geoffrey Eglinton, Huayu Lu and Chi-yue Huang (2006) Leaf  wax lipids as paleovegetational and paleoenvironmental proxies for the  Chinese Loess Plateau over the last 170kyrs. Quaternary Science Reviews 25, 575-594

●   Zhaohui Zhang*,  Meixun Zhao, Xiangdong Yang, Suming Wang, Xuezhong Jiang, Frank  Oldfield and Geoffrey Eglinton (2004) A hydrocarbon biomarker record for  the last 40 kyr of plant input to Lake Heqing, southwestern China. Organic geochemistry 35, 595-613

●   Zhaohui Zhang*, Meixun Zhao, Huayu Lu and Anthony M. Faiia (2003) Lower temperature as the main cause of C₄ plant declines during the glacial periods on the Chinese Loess Plateau. Earth and Planetary Science Letters 214, 467-481

●   Meixun Zhao, Geoffrey Eglinton, Simon K. Haslett, Richard W., Jordan, Michael Sarnthein, and Zhaohui Zhang (2000) Marine and terrestrial biomarker records for the last 35,000 years at ODP site 658C off NW Africa. Organic Geochemistry, 31, 919-930