The Trace Metal Group

François Morel

Professor of Geosciences
Associated Faculty Department of Chemistry
Associated Faculty Princeton Environmental Institute
Associated Faculty Civil and Environmental Engineering

Following my undergraduate education in France, I obtained my Ph.D. in Engineering Sciences from Caltech in 1971 and spent the first 20 years of my academic career in the Department of Civil and Environmental Engineering at MIT. I have been on the Princeton faculty as Professor of Geosciences since 1994. My research explores the interactions between the chemistry and microbiology of aquatic systems, focusing particularly on the transformations, bioavailability and biogeochemical roles of trace metals such as iron, zinc, cadmium and mercury.

Contact Information:
Princeton University, Department of Geosciences, 153 Guyot Hall, Princeton NJ 08544

Phone: (609) 258-2416
E-mail: morel@princeton.edu

Anne Morel-Kraepiel

I obtained my Ph.D. in 2001 in Chemistry at Princeton University. The guiding principle of my research has been to apply to the study of trace metals in terrestrial systems the approaches and methods that have been applied successfully to aquatic systems over the last 30 years. I am particularly interested in understanding how trace metals may limit key reactions of the carbon and nitrogen cycles, and the strategies that microorganisms have developed to acquire essential metals in the complex soil environment.

Contact information:
Princeton University, Princeton Environmental Institute, M25 Guyot Hall, Princeton, NJ 08544

Phone: (609) 258 7415
E-mail: kraepiel@princeton.edu

Jeffra Schaefer

Initially, I worked as a microbial biogeochemist at the US Geological Survey before going on to obtain my Ph.D. at Rutgers University in 2005, where I investigated the role of mercury resistant organisms in limiting methylmercury accumulation in the environment. My research in mercury continued into my postdoc at Princeton University, where I have focused primarily on understanding the mechanism responsible for mercury uptake and methylation, a key first step in its accumulation and biomagnification in the aquatic food web. Although much of my research has focused on the toxic heavy metal, mercury, I have more general interests in bioavailability and uptake of essential trace metals in anaerobic organisms.

Contact Information:
Princeton University, Department of Geosciences, M-32 Guyot Hall, Princeton, NJ 08544

Phone: (609) 258-7438
E-mail: jschaefe@princeton.edu

Oliver Baars

With a background in chemistry (Leipzig University, Germany) and an interest in environmental processes, I did my Ph.D. at the GEOMAR in Kiel (Germany) studying the distribution and speciation of bio important trace metals (zinc, cadmium, cobalt) in the open ocean. The results allow a better understanding of the availability of trace metals to the microbial community and what controls their cycling in the oceans.

In large areas of the open ocean, many bio-important metals, particularly iron, copper and zinc are overwhelmingly bound by strong organic ligands but little is known about the chemical identity of these compounds. The prevalent notion is that such metal species are not available for biological uptake as indicated by laboratory experiments with chelating agents, such as EDTA. However more recent results show that some organic complexes are highly available for biological metal uptake. In my current project I am investigating the relevance of such metal uptake from organic complexes in the environment. Ongoing experiments involve the chemical characterization of different organic species in conjunction with biological uptake experiments.

Contact Information:
Princeton University, Department of Geosciences, 152 Guyot Hall, Princeton NJ 08544

Phone: (609) 258-2489
E-mail: obaars@princeton.edu

Ja-Myung Kim

My research focuses on the impacts of ocean acidification on marine phytoplankton. During my Ph.D. (at POSTECH in South Korea), a main research topic was to investigate the CO₂-induced changes in growth rate of natural phytoplankton assemblages and organic carbon production. As a postdoc in Morel’s group, I am interested in the bioavailability of iron (Fe), an essential cofactor of enzymes utilized in photosynthesis and respiration in phytoplankton, under acidified ocean conditions. The bioavailability of  Fe depends on its binding to organic compounds and the rate of dissolution of Fe minerals.  My aim is to understand how these processes are affected by acidification and the resulting change in the bioavailability of Fe to phytoplankton.

Contact Information:
Princeton University, Department of Geosciences,158 Guyot Hall, Princeton NJ 08544

Sven Kranz
 

During my Ph.D., which I completed at the Alfred Wegener Institute  for Polar and Marine Research and the University of Bremen in Germany in 2010, I worked on carbon acquisition and dinitrogen fixation by the marine cyanobacterium Trichodesmium. My goal is to quantify as well as to understand the underlying physiological mechanisms of the response of phytoplankton to variations in environmental factors during climate change. Using different techniques based on mass spectrometry, fluorescence and molecular biology allows us to study the metabolism of phytoplankton cells in great detail. Understanding cellular responses will allow us to assess future changes in phytoplankton ecology and ocean productivity.
 

Jodi Young

I am interested in the mechanisms phytoplankton use to acquire carbon for photosynthesis. In particular, I am interested in how these mechanisms will respond to changing concentrations of CO₂. Phytoplankton are responsible for about half of the carbon fixed globally through photosynthesis. However, we only have a poor understanding of how this carbon sink will respond to future environmental changes. I completed my Ph.D. at Oxford University in 2011 where I used a range of molecular biological, geochemical and modelling techniques to investigate the sensitivity of these mechanisms to changing CO₂ over geological and modern timescales. One such project focused on the genetic adaptation of the CO₂ fixing enzyme in photosynthesis, Rubisco. The signal of Rubisco adaptation appears to be responding to changing intracellular CO₂ triggered by physiological adaptations to shifting atmospheric CO₂. At Princeton I am continuing this research along with investigating C₄ carbon concentrating mechanisms in diatoms.

Contact Information:
Princeton University, Department of Geosciences, 158 Guyot Hall, Princeton, NJ 08544

Phone: (609) 258-1052
E-mail: jny@princeton.edu

Xinning Zhang

I am a postdoctoral research associate in the Morel group. I obtained a B.S. in Biological & Environmental Engineering from Cornell University in 2004 and a Ph.D. in Environmental Science & Engineering from the California Institute of Technology in 2010. At Caltech, my research touched on the subjects of microbial ecology, symbiosis and its evolution, genetic signatures of trace metals, and the biological basis for hydrogen isotope fractionation.

 My specific scientific pursuits have evolved over time but at a broad scale they are all motivated by my fascination with the interplay between microbiology and the physical environment on both short (transcriptional) and long (evolutionary) timescales.   The challenges associated with comparing studies at vastly different timescales have sparked my more recent interest in understanding the relationships between biological and isotopic datasets.

 In the Morel lab, these broader scientific interests have led me to become fascinated with trace metals and their impacts on N₂ fixation by diverse bacteria.  I am currently working on methods to differentiate between molybdenum, vanadium, and iron types of nitrogenases using pure culture experiments. Doing so will help us understand the functional roles that “alternative” nitrogenases play in nature and, at a broader scale, how trace metals impact the nitrogen cycle.
 
Contact Information:
Princeton University, Department of Geosciences, M32 Guyot Hall, Princeton NJ 08544

Phone:  (609) 258-7438
E-mail:   xinningz@princeton.edu
Personal Website: http://scholar.princeton.edu/xinningz/

Johanna Goldman

I did my undergrad studies in Paris, France, where I studied Chemistry, Physics and Mathematics in the “Classes Preparatoires” at Louis-Le-Grand and then at the ESPCI (Ecole Supérieure de Physique et Chimie Industrielles) where I received a Master of Science in Chemistry (major), physics and biology (minors). I am currently a Ph.D. student in the Morel group studying the effect of climate change on phytoplankton physiology. 

Contact information:
Princeton University, Department of Geosciences, 159 Guyot Hall, Princeton NJ 08544

Phone: (609) 258-2612
E-mail: johannag@princeton.edu

Jenna Losh

I have been a graduate student in the Geosciences Department at Princeton since 2007, working on nitrogen (N)-limited phytoplankton and carbon dioxide (CO₂). Before coming to Princeton, I received my B.S. in biochemistry from the University of Illinois in Urbana-Champaign. The aim of my project is to determine and quantify the response of ocean phytoplankton to increasing CO₂ concentrations by looking at the C:N stoichiometry of the phytoplankton biomass under N-limiting conditions, both in the lab and the field. I am investigating how changes in the C:N ratio reflect changes in cellular stores of carbon and nitrogen and in the concentrations of proteins, such as RubisCO, and carbon storage compounds such as glucans. I am also interested in climate change and ocean policy and am pursuing a certificate in Science, Technology, and Environmental Policy (STEP) with the Woodrow Wilson School at Princeton.

Eva Groves

Contact Information:
Princeton University 
Department of Geosciences
153a Guyot Hall, Princeton NJ 08544

Phone: (609) 258-2390
E-mail: egroves@princeton.edu