Living in two extreme conditions, Indian American astronaut Sunita Williams, aboard the International Space Station and marine biologist Timothy Shank aboard Alvin, the world's first deep-ocean submersible, shared views on their respective jobs.

The 15-minute conversation, which took place on Friday, was broadcast on National Aeronautics and Space Agency Television, following the conclusion of a station status media briefing from NASA's Johnson Space Center in Houston.

The two talked about the similarities and differences in their jobs and compared notes on science and exploration. In addition, they also responded to several queries submitted by students, educators and public.

Speaking from inside Alvin, two miles beneath the Pacific Ocean, Shank talked with Expedition 14 flight engineer Williams.

"Greetings Alvin, this is the International Space Station Alpha, flying about 250 miles above the Earth's surface," Sunita said.

Replying to a question about what alien life forms each of them had seen so far in their separate environments, Sunita said, "We haven't seen anything up here, but I am sure you have seen stuff that looks pretty weird down there."

"Yes, absolutely Suni," said Shank, a researcher with the Woods Hold Oceanographic Institution, adding, "Some of the life forms down here I think of as being aliens."

Despite differences in their research as Shank works in a murky aquatic environment beyond the reach of the Sun, while Williams sees 15 sunrises a day, the two scientists have found a common ground.

"We are both living life in the extremes," Shank said.

At times, the two showed signs of 'status' envy. "Hey, what do you think about switching jobs? I would have loved to do your job and see what's living on the ocean floor. How about coming up here sometime," Sunita asked.

Indian-American Sunita, 41, a Massachusetts native and commander in the US Navy, served as a diver and helicopter pilot prior to being selected as an astronaut. She was a member of a NASA crew in 2002 that lived underwater for nine days in the Aquarius habitat off the Florida coast.

She boarded the space station on December 11, 2006, as a flight engineer for the Expedition 14 crew, joining Commander Michael Lopez-Alegria and fellow Flight Engineer Mikhail Tyurin. She will spend six months on the complex.

Shank, a marine biologist in the Woods Hole's Department of Biology, is currently conducting research diving in the Alvin at the hydrothermal vent field on the East Pacific Rise.

He is leading a National Science Foundation-funded research expedition as part of the RIDGE2000 programme. Alvin is owned by the Navy and operated by Woods Hole as part of the National Deep Submergence Facility.