The Yin and Yang of Nitrogen

Amy Marcarelli studies nitrogen fixation and denitrification in streams across North America.
Amy Marcarelli studies nitrogen fixation and denitrification in streams across North America.
Amy Marcarelli is one of the three women at Michigan Tech to receive an NSF CAREER Award.
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By Allison Mills
Published

There’s more to nitrogen than the letter N. The element and its biogeochemical cycle is the focus of research by Amy Marcarelli, an associate professor of biological sciences. Last year, Marcarelli won a National Science Foundation (NSF) Early Career Award grant to explore two halves of the nitrogen cycle. Her work could flip how we currently think about the nitrogen cycle.

In the nitrogen cycle, the balance of nitrogen fixation and denitrification is not a perfect yin-yang. Unbalanced systems can lead to more than just August pond scum; excess nitrogen is the main driver of the world's dead zones at major river deltas. Marcarelli's research, funded by an NSF CAREER grant, dives into the unexplored side of nitrogen fixation in streams.

Learn more about Marcarelli's research in a few ways:

  • Join @mturesearch Thursday March 17 from 1 to 2 p.m. Eastern for a live chat with @AmyMarcarelli. Follow #mtulive to see the conversation.
  • Don’t worry if you missed the live chat—check out the Storify below.
  • We also break down the yin and yang of nitrogen fixation and denitrification in an infographic.
  • For even more, listen to Marcarelli explain her research with Allison Mills in the video below, with illustrations by Jordan Blahnik and produced by Ben Jaszczak. (Check out the too long; didn't read version up top)

Then, stay tuned this summer as Marcarelli and her research team make their way across North America to measure streams from Puerto Rico to Michigan to Idaho to Alaska. They'll be taking a van that is currently in the shop with a team of mechanical engineering seniors, who transforming it for their senior design project into a transportable ecology lab and classroom. Watch for updates on @mturesearch and #FieldworkFriday.

Watch Amy Marcarelli: Denitrification Career Award video
Preview image for Amy Marcarelli: Denitrification Career Award video

Amy Marcarelli: Denitrification Career Award

 Nitrogen Fixation Infographic

The infographic below explains how nitrogen fixation and denitrification are like a yin-yang. Most of the time, we think the processes balance each other out. However, Marcarelli's research focuses on the fact that nitrogen fixation is rarely measured in streams; that means we're missing an entire half of that yin-yang. Plus, from other studies on lake environments, we know that nitrogen limitation—a cap on how much nitrogen is available for organisms—is influenced by the availability of other nutrients, notably phosphorus.

Nitrogen Fixation infographic

Yin-Yang of Nitrogen: #NSFCareer Researcher Amy Marcarelli

The balance of nitrogen fixation and denitrification is not a perfect yin-yang. Unbalanced systems can lead to more than just August pond scum; excess nitrogen is the main driver of the world's dead zones at major river deltas.Amy Marcarelli's research, funded by an NSF CAREER grant, dives into the unexplored side of nitrogen fixation in stream

Over the next summer, @AmyMarcarelli will be leading a team across North America, gathering samples in streams from Puerto Rico to Alaska to get a better sense of nitrogen fixation. Stay tuned on @mturesearch and mtu.edu/unscripted to learn about the team's work. Here's a local stream where they'll sample.

This is a recap of a live chat with @AmyMarcarelli and @mturesearch from March 17, 2016.

Meet the Processes

@AmyMarcarelli's work focuses on two processes in the nitrogen cycle: nitrogen fixation and denitrification. In undisturbed natural ecosystems, the processes balance each other out, with each part of the cycle driven by certain microbial communities. In a nutshell: nitrogen gas gets converted (via nitrogen fixation) into a new form of nitrogen (ammonium), which is transformed into another kind (nitrate), and is finally changed again and released back into the atmosphere (via denitrification.)

Here is a quick explainer:

Watch Amy Marcarelli: Denitrification TL;DR video
Preview image for Amy Marcarelli: Denitrification TL;DR video

The Balancing Act

Within this big global biogeochemical cycle, @AmyMarcarelli is interested in how nitrogen fixation and denitrification are balanced.

The Other players

Nitrogen is a major nutrient that organisms need to survive. However, it's not the only nutrient.

Summer Streams

Hard to imagine with this picture, but in the summer, the van below will be an ecology powerhouse. Right now a group of @mtuMEEM students are giving the vehicle a make-over to turn it into a transportable lab and classroom.

And all that travel is guaranteed to be better than this:

Michigan Technological University is a public research university founded in 1885 in Houghton, Michigan, and is home to more than 7,000 students from 55 countries around the world. Consistently ranked among the best universities in the country for return on investment, Michigan’s flagship technological university offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, computing, forestry, business and economics, health professions, humanities, mathematics, social sciences, and the arts. The rural campus is situated just miles from Lake Superior in Michigan's Upper Peninsula, offering year-round opportunities for outdoor adventure.

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