University of Southern California

Antifreeze Fish


Nishad Jayasundara, January 30, evening — In 1967, two young scientists, Stanford University graduate students who had spent a winter together doing research in Antarctica, published the article “Temperature Tolerance of Some Antarctic Fishes” in the prestigious journal Science. They reported on three species of Antarctic fish that live in constantly near-freezing waters and can’t tolerate temperatures higher than 6C. This was the lowest upper-lethal temperature reported for any animal — and the record still stands. Forty-three years later, I am reading that same Science article and staring at the majestic Transantarctic Mountains from the third floor of the Crary science building library on the U.S. base at McMurdo Sound.

nishadfish.JPGAs participants in the 2010 Antarctic Biology Course, we have been studying the effects of temperature on a diversity of organisms living under the ice. Our mentor is Professor George Somero, one of the two scientists (along with Dr. Art DeVries, now of the University of Illinois) who made the discovery on the thermal limits of the Antarctic fish four decades ago.

Notothenioids, a group of more than 120 species of Antarctic fish, have evolved at near-freezing temperatures for approximately 14 million years. Many of the Notothenioids have “antifreezes” in their blood that help them survive in freezing seawater. They offer us a unique opportunity to explore the physiological adaptations of fishes to extremely cold and stable temperatures.

Together with Tim Healy, a graduate student from University of British Columbia, I have been focusing on thermal limits of heart function in the same fishes used in Somero and DeVries’ 1967 study. Essentially, our research will provide insights into the challenges of climate change that these marine organisms will face due to warming temperatures predicted to occur in the polar regions.

I wonder if back in 1967, George Somero could have imagined one of his future students sitting comfortably in a library near the Ross Ice Shelf, using wireless Internet to read that article. Did he foresee that the subjects of his fish research would face severe environmental challenges due to human activities thousands of miles away from this icy continent?

Spending this month in Antarctica has made me think more about climate change and its effects on the oceans. And I wonder what we can do to make a difference.

Nishad Jayasundara is a Ph.D. student at Hopkins Marine Station of Stanford.
 
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2 Comments

very nice, thanks for sharing. I like how you bring in the issue of climate change :)
Nishad! I just found this while looking for some info on Art's work to help a student out with a report. Hope all is well and that you are loving your time on the ice! Elizabeth