By H. William Detrich

If you were looking for me at the end of June and thought maybe I’d fallen off the edge of the earth, you wouldn’t have been too far wrong. I was on a ship in the frigid South Atlantic, anchored alongside a tiny island so remote, so fogbound and mysterious, that it was discovered not once but three different times, placed in three different locations, and given three different names.

Bouvetoya Island lies 1,600 kilometers southwest of the Cape of Good Hope. A Norwegian territory, Bouvetoya is twenty-two square miles of volcanic rock covered almost entirely by glaciers. The island was named for French navigator Jean-Baptiste Charles Bouvet de Lozier, who discovered it first, on January 1, 1739. (Lacking an accurate chronometer and forced to rely on dead reckoning, Bouvet plotted it about 200 nautical miles out of its true position.) It’s the most isolated island on our planet.

Why was I in that forbidding place? I was the chief scientist aboard the ICEFISH 2004 Cruise, a research trip that brought an international team of polar biologists to the Subantarctic (the area just north of the Antarctic Circle) for two months. Our mission: To learn more about how cold-blooded fishes and invertebrates survive—indeed, thrive—in these extremely cold, largely unexplored waters.

I first started thinking about putting together such an expedition eight years ago. In 2001, I submitted a grant proposal to the National Science Foundation’s Office of Polar Programs; the grant was awarded the following year. Edison Chouest Offshore and Raytheon Polar Services provided logistical assistance, as well as a research ship and a crew.

After two years of intensive planning, we set sail on May 17 from Punta Arenas, Chile, on the research vessel Nathaniel B. Palmer. On board were thirty-one biologists from Australia, France, Germany, Italy, New Zealand, South Africa, the United Kingdom, and the United States. Our fields of expertise ranged from systematics, ecology, and fisheries management, to biochemistry, physiology, and cell and molecular biology. (One of my students joined the cruise as part of her master’s research program.)

We made stops at the Falkland Islands, South Georgia, the South Sandwich archipelago, Bouvetoya, and Tristan da Cunha—collecting and studying marine species at each location—before disembarking at Cape Town, South Africa, on July 17.

Our days were short (usually about seven hours of daylight) and sometimes extremely cold. In the South Sandwich Islands, for instance, the temperature hovered around -18¾C (roughly 0¾F) with a -40¾C (which corresponds to -40¾F) wind chill. (Antarctica is warmest in January, when temperatures along the coast average slightly below freezing.)

Fortunately, the Palmer—named for the first American to see Antarctica, in 1820—has a steel hull made of an alloy that can withstand temperatures of -60¾C. It’s also equipped with a special ice-breaking capacity, which allowed us to navigate through the thick pack ice we sometimes encountered.

Although the ICEFISH biologists represented many different specialties, two major themes drove our research.

First, we were looking for a baseline understanding of how fishes and invertebrates living in extreme, chronically cold (-1.8¾C, or 28.6¾F) Antarctic coastal waters evolved from ancestral stocks that had lived at much higher temperatures (about 20¾C, or 68¾F). The cold-temperate Subantarctic species are thought to provide an evolutionary snapshot of organisms that populated the relatively warm Southern Ocean some forty to sixty million years ago. What was the “raw” genetic toolbox of those ancestral stocks? How did it change to permit life to flourish at very low temperatures?

Second, as the world experiences climate change, an erosion of biological diversity, and the depletion of marine fisheries, the Antarctic and Subantarctic regions offer relatively pristine laboratories for understanding how organisms adapt—or fail to adapt—to such disturbances. For instance, how will fishes and invertebrates that live at very low, constant temperatures respond if their environment warms? In a sense, polar organisms are highly sensitive canaries in a coal mine, the frontline in registering the impact of global change.

My own research on Antarctic icefish is offering a stunning look at species adaptation, which could potentially lead to some important medical advances.

Fifty years ago, the oxygen-transporter protein hemoglobin, found in red blood cells (erythrocytes), was generally regarded as essential to adult vertebrate life. What a surprise awaited scientists, then, when Norwegian zoologist J. T. Ruud published his seminal article on icefishes, “Vertebrates without erythrocytes and blood pigment,” in the journal Nature in 1954.

Ruud himself had earlier harbored doubts about the existence of the “bloodless” fish that Norwegian whalers reported living in the shelf waters of South Georgia. Then, in 1953, he captured four specimens of the white crocodile fish Chaenocephalus aceratus at South Georgia.

He found their colorless, nearly transparent blood contained white blood cells at less than 1 percent of total blood volume, and no red blood cells or hemoglobin. The oxygen capacity of their blood was 10 to 12 percent of the blood of the related, but red-blooded, South Georgian marbled rock cod and yellowbelly rock cod.

Today, my students and I have shown that virtually all sixteen icefish species have lost the genes needed to produce hemoglobin protein chains. How did this apparently deleterious characteristic evolve? Most likely, globin gene loss could occur only in fishes that live in an extremely and chronically cold environment. Cold water has a higher capacity to dissolve oxygen and other gases. Icefish have large gills and no scales, which allows oxygen to enter all tissues easily. Hence, they can maintain a relatively oxygen-rich blood fluid even without hemoglobin.

Icefish also fail to express many genes necessary to produce the red cells of their red-blooded Antarctic relatives and all other vertebrates. Studying this naturally evolved “knock-out” of red cells allows us to pinpoint genes that produce erythrocytes in “normal,” red-blooded vertebrates. My students and I have already found a new gene, which we’ve named “bloodthirsty,” that plays a critical role in red cell formation.

By understanding the functions of this and other newly discovered genes, researchers may one day be able to develop new therapeutic drugs to treat the anemias that result from kidney dialysis or chemotherapy.

The ICEFISH expedition produced other significant discoveries. For example, one deep-sea trawl (1.7 miles down!) netted an extremely rare cusk eel, a major find. It may be only the second specimen of this ophidioid fish ever found in the Southern Ocean (the first was collected in 1906). Or it could represent a completely different, previously unknown species.

The large variety of organisms we collected will be studied by more than twenty different research groups, and the results of our work won’t be fully known for many months and years to come. But it’s already clear our cruise was a huge success.

And take it from me: When you’re eager to get away from it all, forget the quiet Caribbean beachfront. I know a little spot that really does feel like the last place on earth.

H. William Detrich is a professor of biochemistry and marine biology. For more information on the ICEFISH 2004 Cruise, visit <www.icefish.neu.edu>.