Searching for nitrogen fixers

By: Yubin Raut

My name is Yubin Raut and I am a fourth-year graduate student in the Capone lab where our primary focus is investigating different aspects of the marine nitrogen cycle. Nitrogen, an important constituent of many of life’s building blocks (e.g. nucleic acids, amino acids), is essential for all living things. Despite making up ~78% of our atmosphere, most organisms cannot tap into this large reservoir of dinitrogen (N2) gas to satisfy their nitrogen demands. Biological nitrogen fixation is the process by which microbes (bacteria and archaea) convert N2 gas into a biologically usable form of nitrogen (i.e. ammonia) that’s accessible to other organisms.


I am very lucky to receive the 2019 Wrigley Summer Fellowship as it allows me to spend another summer at the Wrigley Marine Science Center (WMSC) investigating the potential interactions that these nitrogen fixers have with marine macroalgae. Marine macroalgae are vital to coastal ecosystems where they serve numerous different ecological functions (e.g. create habitats, provide food source).

As of recently, macroalgae are also gaining a lot of attention from various aquaculture, pharmaceutical, and biofuel industries. Macroalgal productivity is largely dependent on light (for photosynthesis) and their ability to acquire key nutrients such as nitrogen. As associations with nitrogen fixers could potentially alleviate this nitrogen limitation, I will be sampling the rich assemblage of benthic macroalgae surrounding Santa Catalina Island to investigate if they host nitrogen fixing microbes. A large part of my research involves free diving around local sites such as Isthmus Reef to collect macroalgae to bring back to the lab to set up incubations to measure rates of nitrogen fixation associated with the seaweed.

Fortunately, I don’t have to do all this work by myself as I got another chance to mentor an undergraduate student involved in the summer Research Experiences for Undergraduates (REU) program. With their help, we plan on carrying out lots of experiments and have a full research load planned ahead of us.


2018 REU Calyn Crawford measuring nitrogen fixation rates on a gas chromatograph

In addition to doing research, I am also anticipating plenty of fun opportunities to volunteer with education and outreach programs for various groups (e.g. high school students) visiting the island. Most of these opportunities involve leading snorkels around Big Fisherman Cove and kayaking to different sites such as Bird Rock and Blue Caverns so people get an opportunity to explore the natural beauty surrounding Catalina. With the recent resurgence of giant kelp, it is inevitable that we encounter these complex underwater ecosystems during snorkels which will give me the chance to share my project with these different groups and encourage the next generation of students to become involved with marine research.