Staying with Sargassum

By: Calyn Crawford (Univ. of South Carolina, ’20)

The Wrigley Institute 2018 NSF REUs (Research Experiences for Undergrads) have made it to the island! Upon arrival onto beautiful Catalina Island, I looked around to find stunning ocean views juxtaposed with a dry, desert-like land mass. Searching the sleep-deprived, slightly sea sick eyes around me around me, I realized everyone still had a smile on their face and knew I had chosen the right REU program to apply for. Just in the short two weeks I’ve spent in California, I’ve gotten to meet a fantastic group of fellow REU students, mentors and locals.

The 2018 class of WIES REU students

The 2018 class of WIES REU students

Life on Catalina Island is composed of a complex system of well-oiled parts working in sync to promote sustainability and produce cutting edge research. This program has given me endless resources, research experience, confidence, networking, and educational opportunities. These in turn have helped guide me along my career path. As a junior marine science major with a chemistry minor at the University of South Carolina, I feel as though I’ve found my niche. My mentors from USC, Dr. Doug Capone and graduate mentor Yubin Raut, have supported me and helped get my feet under me in the beginning stages of the project. They have patiently corrected mistakes and answered questions, and for that I am incredibly grateful.

My project examines nitrogen fixation associated with the decomposition of different local macroalgae (for example, an invasive species called Sargassum horneri). Broadly, nitrogen fixation is a crucial part of both terrestrial and marine systems since most of the world’s nitrogen is in a gaseous form (N2) and biologically unavailable to most organisms as it is energetically taxing to break the strong triple bond connecting the two nitrogen atoms. However, nitrogen is a pertinent molecule for all living organisms since it is a building block of nucleotides in DNA/RNA, and amino acids which form proteins. Nitrogen fixation is the process carried out by specialized bacteria or archaea (diazotrophs) which utilize the nitrogenase enzyme to convert N2 to biologically usable forms such as ammonia. We can indirectly examine nitrogen fixation associated with macroalgae using the acetylene reduction method which analyzes ethylene production over a time period using a gas chromatograph (GC).

Left: Measuring one of our samples of Eisenia arborea; Right: Aliquoted samples.

Left: Measuring one of our samples of Eisenia arborea; Right: Aliquoted samples.

However, life on Catalina hasn’t been all work! The island is an outdoor playground suitable for anyone wanting to stretch their legs. Catalina offers spectacular views from the Miss Christi, on top of a mountain, in a kayak, and even from Two Harbors! While I still have much to learn and explore about the island and scientific research, I couldn’t be happier being able to do it in a place I’ve come to love with people I’ve come to cherish.