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anbarlab Researchers in my group use chemical concepts and approaches to study geological, chemical and biological processes that shape the Earth's surface environment and how they have changed through time. Study of these processes teaches us about the habitability of the Earth, the history of the environment and life, the effects of human activities on the environment, and the prospects for life beyond Earth. Our efforts center on the development and application of novel analytical techniques, particularly using mass spectrometry.

Recently, we have been among the pioneers in using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) to precisely measure mass-dependent variations in the isotopic compositions of transition metals, particularly iron and molybdenum. Work by us and others documents that variations of 0.01 - 0.1 %/amu, once undetectable, are actually ubiquitous. Such measurements in natural samples, informed by laboratory experiments and theoretical studies, provide insights into the environmental chemistry of metals and the metal-centered interactions between organisms and their surroundings. Applied to the geologic record, such "metal stable isotope" studies provide information about metal biogeochemical cycles on the ancient Earth, environmental changes that perturbed these cycles, and biological activity in the distant past.

A notable recent example of this research is our use of molybdenum isotopes to study changes in the oxygen content of the oceans through time (Arnold et al., 2004). We plan to continue to explore the biogeochemistry of metals in the middle of the periodic table, using isotopic and other methods. We are especially interested in "metallomic" research that relates the distribution and isotopic composition of metals in nature to the demand for these metals by various metalloenzymes. New state-of-the-art analytical facilities, particularly in the W. M. Keck Foundation Laboratory for Environmental Biogeochemistry, make ASU an exceptional setting to pursue this research. 

  Anbar Group Fall 2007

Front row: Yun Duan, Jennifer Glass, Nahks Tr'Ehnl, Laura Wasylenki, Gwyneth Gordon, Tracy Lund.

Back row: Brian Kendall, Gabrielle Montanez, Bryan Rolfe, Jennifer Morgan, Ariel D. Anbar, Brian Majestic, Greg Brennecka.

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Featured Research
Astrobiology



Follow the Elements! An award from the NASA Astrobiology Institute allows us to look beyond requiring water for life, and try to understand what other elements - including many metals - are necessary. We look at extreme environments on Earth, including Yellowstone hot springs, Mo-poor lake environments and As-rich environments to see the role that different elements assume depending on their environmental availability. Did V- and Ni- hydrogenases evolve before those using Mo? Could life be based on As instead of P? At extremes of temperature and pH, how does life handle its energetic requirements? Is the Shadow Biosphere real? By better understanding the range of life on our blue planet, we can better guide where we look for life - and how to recognize it - elsewhere in the Solar System and beyond.

Recent News
Jennifer Glass' new publication in Limnology and Oceanography

Jennifer Glass has a new publication in Limnology & Oceanography Molybdenum-nitrogen colimitation in freshwater and coastal heterocystous cyanobacteria


Astrobiology All Hands meeting hosted by ASU

An All Hands meeting of ASU's "Follow the Elements" Astrobiology group on January 25-26th, 2010 successfully brought together the many investigators and updated them all on the progress of research.


Greg Brennecka's paper appears in Science

Greg Brennecka is lead author on a paper appearing in the January 22nd, 2010 issue of Science. Coauthored with Stefan Weyer, Meenakashi Wadhwa, Phil Janney, J. Zipfel and Ariel Anbar, this paper measures the 238U/235U ratio in meteorites and suggests that the Solar System's early clock must be adjusted by as much as five million years.


Ariel publishes another article in Science

Ariel is a coauthor on four papers in the journal Science that have emerged out of study of cores in Western Australia from early in Earth's history. The latest is in the October 30th issue.


Greetings and Farewells

This summer we bid a sad goodbye to postdoc Brian Majestic, visiting scientist Tsuyoshi Komiya and undergraduate Bryan Rolfe, and welcomed postdoc Amisha Poret-Peterson and lab technician Carina Arrua.


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