Waters in the Gulf of Alaska were surprisingly acidic this summer, an indication they are absorbing high levels of carbon dioxide. Farther north, a polar bear in search of food wandered dangerously close to a town where it would have been killed. And along the Northwest Passage from Alaska to Greenland, Inuit people told stories of their ice becoming too thin for them to walk across.

These and other observations were the work of the sailors and scientists on board the ship Ocean Watch. The job of the crew's four members does not end there. Half their mission is to share these stories and engage people in thinking about ocean health at each of the expedition's 31 stops in its clockwise circumnavigation of North and South America.

This week, Ocean Watch, which left Seattle at the end of May to embark on a 13-month voyage, reached the Intrepid Sea, Air and Space Museum on the Hudson River in Manhattan. New York City marked mile 9,000 of the 64-foot ship's 25,000-mile voyage. Hundreds of city school children and curious adults, who might have been drawn to the bright orange octopus on the ship's sail, came to learn about the floating science laboratory.

"We can go out and take key measurements. The public is following along and it gives them a sense of involvement, a sense of ownership" of the problems facing ocean conservation, says Michael Reynolds, the crew's oceanographer who has spent 40 years on more typically sized, 300-foot research vessels. He describes the opportunity to combine science with his passion for sailing as having "won the lottery."

To explain to people how climate change is affecting ocean health, Reynolds often talks about the Gulf of Alaska's low pH. As the expedition continues southward, he expects to find other signs of the ocean's failing health to share. For example, the crew is collecting water samples at each port to see if jellyfish have become more abundant, which would indicate that the local marine ecosystem is out of balance.

In addition to serving as a vehicle to deliver messages about the ocean, the experiments aboard Ocean Watch are part of collaborations with eight different universities and agencies. The samples of jellyfish will make their way to the University of Southern California where scientists will analyze their DNA. In the Northwest Passage, the Ocean Watch crew put three buoys in the water, which will help the International Arctic Buoy Programme at the University of Washington in Seattle make weather and ice predictions. And, on a daily basis, cameras on the ship's boom capture 48,000 images of the sky and sea. NASA is using pictures of the clouds in these images to complement data collected from its satellites for a better understanding of cloud formation and, in turn, climate modeling.

Folks who visit Ocean Watch at their hometown port will be treated to some more upbeat lessons that balance the despairing messages about the changing seas. The educator on board for the first leg of the journey, Zeta Strickland, a teacher from the Pacific Science Center in Seattle, shows school kids at the different ports an underwater, remote-controlled camera called the Sea Perch, developed at M.I.T. She says it is simple enough for middle school students to build. The captain of the crew, Mark Schrader, joked that this little device would make a great Christmas present, as part of his presentation at the Intrepid Museum Wednesday evening.

Perhaps the most stunning stories told at the presentation were conveyed via the photographs of crewmember David Thoreson who, in 2007, became the first American to sail the Northwest Passage. His photos captured some of the peril that the Ocean Watch crew faced as their 44-ton ship came within what looked like mere feet of potentially crushing 500-ton ice sheets in the Passage.

Thoreson says the adventurous spirit of the Ocean Watch mission helps engage people in the science and the story of the lives affected by climate change in a way that is not political and does not polarize.

Today, Ocean Watch will push out off for Charleston, S.C. It will follow a tight schedule, Schrader says, to make it the rest of the way south to Cape Horn by early January, when conditions are right to circle the tip of South America. By July 4, 2010, he expects to return to Seattle, having completed a full circle in just over a year.

The project was developed by Sailors for the Sea, a nonprofit organization founded by David Rockefeller, Jr., in partnership with the Pacific Science Center. The monthly $50,000 operational costs are funded by The Tiffany & Co. Foundation, Unilever, The Rockefeller Family and The Osberg Family Trust. The aim of Ocean Watch is to make sailors and all citizens of the Earth better stewards of the sea.*

*Note (10/13/09): Due to an error, this sentence has been modified since the original posting.

Image courtesy of David Thoreson