Trees get all the attention when it comes to oxygen production, but half of the world’s supply is produced in the oceans by a number of species of bacteria. A major contributor is Prochlorococcus, the smallest marine bacteria, which nevertheless is estimated to be responsible for some 31 percent of oxygen production by upper-ocean bacteria. Prochlorococcus flourishes in the warm waters of Earth’s tropical seas (there are roughly 100,000 cells in a milliliter of ocean water), but what will happen as the oceans become increasingly acidic due to climate change?
That’s a question that grips senior Matthew Kuhl, the first student in UAB’s new Accelerated Bachelors/Masters Program in Biology. (The program allows students to be dual-enrolled in the bachelor’s and master’s programs in biology and earn his bachelor’s and master’s degrees in five years or less.) “Increasing acid levels affect Prochlorococcus by affecting Alteromonas, another type of bacteria that grows in the ocean with them,” Kuhl said. Alteromonas produces an enzyme, catalase, that helps Prochlorococcus grow. “We expect that the increasing acid levels in the ocean will negatively affect growth of Alteromonas, which will affect growth of Prochlorococcus,” Kuhl said. “If it is significant enough, that could be disastrous.” Kuhl will share his early progress at the 2019 Spring Expo on April 19.
For the past several months, Kuhl has been working in the lab of Assistant Professor Jeffrey Morris, Ph.D., in the Department of Biology, on the early stages of an experiment to find out just how significant will be the effect of rising ocean acidity on Prochlorococcus oxygen production. The work involves controlling for many different variables, including purifying the Alteromonas and Prochlorococcus strains. It’s not as simple as cranking up acid levels in the lab and measuring the results. By the time oceanic carbon dioxide levels reach their predicted levels in the year 2100, the rapidly evolving Prochlorococcus and Alteromonas will have changed along the way. So Kuhl is tapping into the Morris lab’s Long-Term Phytoplankton Experiment — a “really cool resource,” Kuhl said — that uses experimental evolution methods to gain understanding of how marine microbial populations will change in response to climate change.
“We have bacteria that have been evolved over 500 generations,” Kuhl said. “They have been growing in the predicted CO2 levels of the future. We’re comparing how these bacteria grow to the type in the ocean today.” As Kuhl noted in his Expo abstract, “understanding risks to important oxygen producers could help us develop solutions or spur climate change control to minimize negative global effects.”
Kuhl, who is a member of the University Honors Program in the UAB Honors College, has always been interested in microbiology and specifically microbiotechnology, which involves harnessing microbes “to grow biofuels and biomaterials,” he said. UAB’s strong microbiology program drew the Winter Park, Florida, native to Birmingham. “I had a really strong experience with Dr. Austad [biology chair Steven Austad, Ph.D.] and Dr. Watts [biology graduate program director Stephen Watts, Ph.D.],” Kuhl said. “They met with me personally and have kept in touch as my mentors throughout my time as an undergraduate.”
After he graduates with his master’s degree, Kuhl plans to enter the job market. “I was originally interested in the academic side of things,” he said. “But I’m very interested in microbiotechnology and biofuels and I’ve come to the decision that I’d rather be involved in an industrial setting. I may decide to come back for a Ph.D. later, but I’m ready to go out and do something first.”
Matt Windsor, UAB, 18 April 2019. Article.
