Welcome!

Welcome to the first edition of Rock, Metal, and Water: Le GEM Blog! I am excited to begin this new endeavor as a blogger chronicling the exploits of the GEM lab at Central Michigan University. My name is Dr. Meghan Wagner, and currently I am a postdoctoral researcher working with Professor Anthony Chappaz. I earned my bachelor’s and master’s degrees in chemistry, and last year I completed my Ph.D. in earth and environmental sciences. Having a background in both chemistry and earth science allows me to act as a bridge between the two sciences, and—I think—to look at earth science problems in nontraditional ways. My personal research interests involve trace metal geochemical cycling, climate, and the relationship between ocean circulation and oxygen concentrations in the deep ocean.

The purpose of this blog is to give all of my readers an insider’s view of what happens in an academic research laboratory, and what the life of one postdoc is like. Each Friday, I will share our successes and failures, bring my readers along for fieldwork and conferences, and try to bring some clarity to scientific concepts and instrumentation that we will run across. Above all I want this blog to be widely accessible and fun to read! I am sure that my writing style and skill will improve with more practice, and so I ask that you, my readers, please contact me with questions, comments, and suggestions for things that you would like me to blog about.

I hope that you will take a few minutes to explore the GEM lab website to learn more about the people, our research interests, and facilities. Briefly, we are aquatic geochemists interested in trace metal chemistry. In other words, what are the trace metal concentrations in aquatic waters and sediments? What can trace metals tell us about nutrient cycling, primary productivity, oxygenation, and pollution? How and why are trace metals preserved? How are trace metals transported through aquatic and terrestrial systems?

And what are trace metals? Trace metals are metals present in small quantities—around the part per million (ppm) or part per billion (ppb) level. Usually this means transition metals, also known as d-block elements. There is a wonderful website www.webelements.com that has a wealth of information about all of the known elements. The transition metals are the ones colored in pink. Some of these elements are probably known to you, such as zinc (Zn) and copper (Cu), while others may be unfamiliar, such as scandium (Sc) and ruthenium (Ru). In human physiology, elements like zinc and copper are essential micronutrients. The same is true for other organisms—more on this later.

In our laboratory, we are especially interested in the interaction of the metal molybdenum (Mo) with dissolved organic matter (DOM). DOM is a complex mixture of naturally occurring organic molecules. The size that constitutes “dissolved” is not universally agreed on, but one common definition is anything that will pass through a 0.45 micrometer filter. For comparison, human hair is approximately 80-100 micrometers wide. So we are interested in very small things! Last Friday Anthony and I went out to the field to collect some DOM for our experiments. Here in central Michigan, we have recently had a lot of rain, which has washed organic matter produced by trees and other plants into the Chippewa River. So that day “the field” was a local park. Here I am collecting river water into a carboy.

Yes, that’s right: For my job, sometimes I get to play in the river. Neener neener, desk denizens! Afterward we brought the river water back to the lab and filtered it to remove the large particles. Here you can see the filtration in progress and what we collected on the filters.

The carboys are sitting in black plastic trash bags to protect the DOM from light. This is because some DOM is broken down by light (photodegradation), and we want to preserve our sample. The next step was to concentrate the DOM using a reverse osmosis system built in-house by one of our lab volunteers, Jacob Spreitzer. Here is the reverse osmosis system and the concentrated DOM sample (on the right, clean water on the left for comparison).

After a resin treatment to remove metals bound to the river DOM, we have a DOM sample ready to use!

So long for now! Next Friday will be very exciting because I will be writing from the Advanced Photon Source at Argonne National Laboratory where Anthony has been awarded beam time.