Abundant ammonia aids life's origins

March 2, 2011

An important discovery has been made with respect to the possible inventory of molecules available to the early Earth. Scientists led by Sandra Pizzarello, a research professor at Arizona State University, found large amounts of ammonia in a primitive Antarctic asteroid. This high concentration of ammonia could account for a sustained source of reduced nitrogen essential to the chemistry of life.

The work is being published in this week’s Proceedings of the National Academy of Sciences (PNAS). The paper is titled, “Abundant ammonia in primitive asteroids and the case for a possible exobiology,” and is co-authored by Pizzarello, geologist Lynda Williams, chemists Gregory Holland and Jeffery Yarger, all from ASU and Jennifer Lehman of UC Santa Cruz. Download Full Image

The finding of a high concentration of nitrogen-bearing molecules in an asteroidal environment shown by the new study is very provocative. Besides the noble gases, nitrogen is the fourth most abundant element in the Sun and the universe overall. On the Earth, it is an indispensable ingredient of the biosphere, being essential to DNA, RNA and proteins. In other words, it is necessary for life's information transfer and catalytic processes.

“All origins-of-life theories need to account for a sustained source of reduced nitrogen in order to make amino acids and nucleobases,” said Pizzarello, who works in ASU’s Department of Chemistry and Biochemistry in the College of Liberal Arts and Sciences.

On the early Earth, on the other hand, the prebiotic inventory of reduced nitrogen necessary for the formation of N-containing biomolecules has been difficult to predict. The hypotheses of a reducing atmosphere had initially allowed one to envision considerable ammonia abundance as well as evolutionary pathways for the production of amino acids. However, the current geochemical evidence of a neutral early Earth atmosphere, combined with the known photochemical destruction of ammonia, has left prebiotic scenarios struggling to account for a constant provision of ammonia.

An abundant exogenous delivery of ammonia, therefore, might have been significant in aiding early Earth's molecular evolution, as we should expect it to have participated in numerous abiotic as well as prebiotic reactions.

It also is interesting to note that the new PNAS work was made possible by the finding in Antarctica of these exceptionally pristine, ammonia-containing, asteroidal meteorites. Antarctic ices are good “curators” of meteorites. After a meteorite falls – and meteorites have been falling throughout the history of Earth – it is quickly covered by snow and buried in the ice. Because these ices are in constant motion, when they come to a mountain, they will flow over the hill and bring meteorites to the surface.

Jenny Green

Clinical associate professor, School of Molecular Sciences


Education entrepreneurs seek funding for web mentoring program

March 2, 2011

In the world we live in competitions can only have one of two outcomes, you either win or you lose. More than likely we have all been a part of the loosing train at one point or another. The question is, how long will it take for you to get off that train and on to a better one.

For Stephanie Garcia and Tracy Geiger, two graduate students at the Mary Lou Fulton Teachers College, the trip was less than 24 hours. Download Full Image

Garcia and Geiger are the two masterminds behind the idea of the Mobile Mentor Program, an interactive networking site geared to students who don’t believe that college is for them.

“Its conceptualized as an E-mentoring program so secondary students or students who are in either middle school or in high school will end up connecting with current college students and those college students will serve as their mentor,” said Geiger.

Secondary students will have the opportunity to learn what college is really about, why it is important and then they will be connected to a current college student who will sustain excitement for college. Having the program based online allows time and travel constraints to disappear.

The idea stemmed from the well below average graduation rates of high school and college seniors. Garcia and Geiger soon found that their idea had potential when they became one of 30 finalists from over 150 teams at ASU’s Innovation Challenge.

“It was a big shock for us that we even made it past the first round,” said Garcia.

The second round of eliminations arrived with Garcia and Geiger as the first team of the day to compete. With no one to watch as an example the tag team found themselves relying on practice and luck.

However, it was here that the Mobile Mentor Program lost.

“We get disappointed but not discouraged,” said Garcia. She believes that they have planted the seed for their program and already they are receiving great responses from the community.

The two are unsure on the next type of funding opportunity they will pursue whether it be through ASU, nationally or both.  What they do know, is that the program will be moving forward.

With a competition dominated by engineers, businessmen and scientists, the defeat could have been the end of the Mobile Mentor Program.  Ironically, it ended up being a blessing in disguise.

Garcia and Geiger did not allow one door closing to hinder something they are so passionate about. The opportunity in itself was an accomplishment nonetheless.

“So we failed,” said Garcia, “we will get back on the horse and we’re gonna try again.”

Clarissa Tapia
, Clarissa.Tapia">mailto:Clarissa.Tapia@asu.edu">Clarissa.Tapia@asu.edu
ASU News intern