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How will cold-loving Antarctic fish respond to warming ocean waters?

With a new NSF grant, Northeastern professor William Detrich will study how rising ocean temperatures will affect the development of the embryos of these fish and the growth of juveniles after hatching

Northeastern University

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IMAGE: This is Northeastern professor William Detrich in his lab at the Marine Science Center in Nahant, Massachusetts. view more

Credit: Photo by Matthew Modoono/Northeastern University

Antarctic fish are a vital com­po­nent to the food web that sus­tains life in the cold Southern Ocean that sur­rounds Antarc­tica. They feed on smaller organ­isms, and serve as meals for the bigger ones. But little is known about how the rapid rate at which these waters are warming will affect the devel­op­ment of fish embryos and their growth after hatching, according to North­eastern pro­fessor William Detrich.

Answers to these ques­tions, he said, are needed to under­stand how the ecology of the Southern Ocean may be per­turbed by cli­mate change.

Det­rich, who is an expert in marine mol­e­c­ular biology and bio­chem­istry, has received a four-year, $1.25 mil­lion award from the National Sci­ence Foun­da­tion for a project that will sup­port his con­tinued research to address what he calls a crit­ical research gap.

"The Antarctic Penin­sula is the hot zone right now for warming oceanic waters," Det­rich said. "Along the penin­sula, the Southern Ocean is warming faster than any other ocean on the planet. That's a big driver for this research. We're working in an area that is really demon­strating cli­mate change."

Tem­per­a­ture read­ings:

Det­rich pointed to the Inter­gov­ern­mental Panel on Cli­mate Change's esti­mates that the Southern Ocean around the penin­sula could rise between two and five degrees Cel­sius over the next one to two cen­turies. At the present time, the body tem­per­a­tures of Antarctic fishes fall in a very narrow range deter­mined by their cold habitat--between minus 1.9 degrees and plus 2 degree Celsius--and the long-term objec­tive of Detrich's project is to under­stand whether these fish are equipped to respond and adapt to higher tem­per­a­tures as the Southern Ocean warms.

"For organ­isms like fish that have adapted to very cold habitat tem­per­a­tures over a long period of time, 50 mil­lion years, the chal­lenge of a rapid tem­per­a­ture increase will be a real shock to their phys­i­o­log­ical sys­tems," he said. "The ques­tion is: are they capable of dealing with that?"

More co-ops coming to Antarc­tica:

Det­rich is in the Col­lege of Sci­ence and is based at Northeastern's Marine Sci­ence Center in Nahant, Mass­a­chu­setts. Over the past three decades he's made many treks to Palmer Sta­tion in Antarc­tica to study ice­fish and other species native to those waters, and since 2010 stu­dents have joined him there for co-op expe­ri­ences. He said this new project will lead to even more co-ops in the win­ters of 2016 and 2018.

"I'm proud that my research has pro­vided the oppor­tu­nity for many under­grad­uate and grad­uate stu­dents to gain invalu­able expe­ri­ence in expe­di­tionary bio­log­ical sci­ence, a unique example of expe­ri­en­tial learning set in the last place on Earth," he said.

What the research will involve:

In this project Det­rich will assess the effects of ele­vated tem­per­a­tures on embryo via­bility, on the rate of embryo devel­op­ment, and on the gene "toolkits" that respond to tem­per­a­ture stress. He and his team will focus on two related species, one a red-blooded rockcod, the other a white-blooded ice­fish. For each species, there will be one group raised at cur­rent water tem­per­a­tures (0 degrees Cel­sius) and another at the pre­dicted ele­vated water tem­per­a­ture (plus 4 degrees Celsius).

As part of his project, Det­rich will eval­uate how and why the white-blooded fishes evolved to no longer pro­duce red blood cells, a defect that may make its embryos par­tic­u­larly vul­ner­able to heat, he said.

This research, he hopes, will help pro­vide the public and pol­i­cy­makers more data to inform deci­sion making around strate­gies to address cli­mate change, par­tic­u­larly pro­tecting life in the Southern Ocean.

Det­rich noted that there are two extreme out­comes that could result from rising tem­per­a­tures. One is that higher tem­per­a­tures will be very dis­rup­tive to devel­op­ment and the fish embryos will die. The second is that the fish would live, but they'd develop much more rapidly. In the latter case, he explained, the fish would hatch ear­lier than normal, in the dark win­ter­time when their food source--phytoplankton, which requires light--hasn't bloomed yet.

"Under the rapid devel­op­ment sce­nario, what you'd have is a larval fish looking for food and per­haps not finding it," he said.

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