Phytoplankton are the oceans’ canaries in a coalmine for USF’s Deneb Karentz, which is why she travels to one of the coldest places on earth to learn how these microscopic life forms are adapting to climate change.
Her three-year research project in Antarctica is among the first to investigate how phytoplankton respond to seasonal changes in temperature and light at a genomic level. Phytoplankton are the foundation of the ocean’s food web, and their health affects larger marine life, from fish to birds to whales, said Karentz, professor of biology and environmental science.
“Our main hypothesis is that the differences between phytoplankton species that succeed and those that don’t can be identified at the molecular level,” said Karentz. “This could provide important insight into how phytoplankton cells respond to environmental changes, such as global warming, ozone depletion, and ocean acidification.”
Some phytoplankton species, of which there are hundreds, thrive in the cold and dark of the Antarctic winter, but others multiply in summer, with its longer daylight and warmer waters. Karentz is trying to understand which of the phytoplanktons’ genes “turn on” or “turn off” with these changes in heat and light.
Austin Gajewski ’13 and Bethany Goodrich ’11 accompanied Karentz to the cold continent. They helped with everything from collecting water samples and counting phytoplankton to measuring sea temperature, salinity, and clarity at different depths.
Bethany Goodrich ’11, researcher Joseph Grzymski, and USF
Professor Deneb Karentz (from left) collect water samples after
cutting a hole in the Antarctic ice between storms.
Gajewski, a biology major, called his experience “invaluable” but was shocked by how time-intensive the research was. “Each data point we collected required going out on the ocean for several hours then several more hours analyzing it back in the lab,” he said. “To make proper scientific observations takes much longer than I ever imagined. Textbooks never really go into all the experiments behind the results they teach.”
With its extreme variations in temperature and light, Antarctica may be ideal for this research, but it’s not ideal for the researchers. “During our field season at the end of winter and early spring, we dealt with harsh weather conditions in Antarctica, where temperatures dropped to about 10 degrees Fahrenheit,” Karentz said. Winds raced to 70 mph and the sea froze over, preventing the team from boating to water sampling sites more than once. “The field work was very challenging,” said Karentz, who has conducted research at Palmer Station, Antarctica since 1986.
The team saw seabirds, seals, and whales almost daily. Penguins, who have no natural land predators in Antarctica, would walk right up to Gajewski and Goodrich out of curiosity.
“All Antarctic life is magnificent, from the microscopic to the grandiose,” said Goodrich, who is working on a graduate degree at the University of Oxford’s School of Geography and the Environment. “I wasn’t particularly surprised at how much I adored them. I dare you to find someone who doesn’t light up and grin when a penguin saunters over to him or her.”
The project is a collaboration with Joseph Grzymski from the Desert Research Institute in Nevada. The work is funded by two grants worth more than $700,000 from the National Science Foundation.