Carolyn Buchwald

Canada Research Chair in Ocean Chemistry

Tier 2 - 2017-11-01
Dalhousie University
Natural Sciences and Engineering Research Council


Coming to Canada From

Woods Hole Oceanographic Institution, Massachusetts, United States

Research involves

Using nitrogen and oxygen isotopes to decipher nitrogen biogeochemistry in the ocean.

Research relevance

This research will provide insights into ways to remove nitrogen pollution from coastal waters.

Microbes Teach Us the Best Way to Keep Our Ocean Clean

Have you ever been to a beach or pond that was too green and slimy to swim in? Those conditions are usually thanks to an overgrowth of algae, which in turn is caused by an over-abundance of nutrients—specifically nitrogen.

Humans have been rapidly increasing the amount of nitrogen in the environment by producing fertilizers that will help grow food to support the ever-growing global population. Most of this nitrogen ends up in our oceans.

While nitrogen is important for all life, it can be harmful in high doses, causing excessive growth of algae and other microscopic organisms, like bacteria. These microbes breathe all the oxygen out of the water, causing fish and larger organisms to suffocate and die. They also lead to the unsightly, foul-smelling green slick of algae that humans find so off-putting. This phenomenon is known as eutrophication.

Dr. Carolyn Buchwald, Canada Research Chair in Ocean Chemistry, has been tackling this problem using “pet microbes.” Grown in her lab, these special microbes can use nitrogen instead of oxygen to breathe. When they use the nitrogen, they convert it from a dissolved form in the water back to a gaseous form, removing it from the water and cleaning up the environment in the process.

To study how this works, Buchwald and her research team use chemical labels called stable isotopes. They grow the microbes, measure the effect they have on the stable isotope content in nutrients, and use this information to track their growth in the natural environment. Ultimately, Buchwald’s research could point to new ways to remove nitrogen pollution from coastal waters.