The Marine Environment

Glacier Bay's marine environment

If you sail through Glacier Bay today, you will travel along shorelines and among islands that were completely covered by ice just over 200 years ago. When Captain George Vancouver charted the adjacent waters of Icy Strait in 1794, he and his crew described what we now call Glacier Bay as just a small, five-mile indent in a gigantic glacier that stretched off to the horizon. That massive glacier was more than 4,000 feet thick in places, up to 20 miles wide, and extended more than 100 miles to the St. Elias mountain range.

By 1879, however, naturalist John Muir discovered that the ice had retreated more than 30 miles, forming an actual bay. By 1916, the Grand Pacific Glacier - the main glacier credited with carving the bay - had melted back 60 miles to the head of what is now Tarr Inlet. Such rapid retreat is known nowhere else.

In 1925 President Coolidge signed a proclamation that created Glacier Bay National Monument for its tidewater glaciers, developing forests, scientific opportunities, historic interest and accessibility. Finally in 1980, after decades of talk, Glacier Bay's status was elevated to that of a national park. Further protection and recognition of Glacier Bay's significance occurred in 1986, when the Glacier Bay-Admiralty Island Biosphere Reserve was established under the United Nations Man and the Biosphere Program. In 1992 Glacier Bay became part of an international World Heritage Site, along with neighboring Wrangell-St. Elias National Park and Canada's Kluane National Park.

In 1999, after great controversy, the National Park Service (NPS) created America's largest temperate marine reserve by closing commercial fishing in parts of Glacier Bay National Park, Alaska. During the 1990s, collapsing fisheries around the world caused doubt about the long-term sustainability of certain fisheries, especially crab fisheries. An emerging theoretical and empirical body of information hypothesizes that "no-take marine reserves" may promote marine biodiversity, increase scientific understanding, and enhance the long-term sustainability of many fisheries.

This unit invites students to learn more about this unique and pristine marine wilderness. They will investigate the complex oceanography of the bay to describe the wide variety of ecosystems within its waters. They will determine why Glacier Bay could be awarded a "Biodiversity Award for the Year" by studying the abundant phytoplankton blooms on which the entire ecosystem rests. They will also use the Bay's natural history to predict the effects of global warming on the area.

This unit is designed for grades 5-8. Activities and handouts usually will be written to upper elementary and lower middle school levels with some Extensions to adjust for the younger and older students.



Unit Outline

Instructional Resources

Activity 1:
Setting the Scene

Activity 2:
Glacier Bay: Prime Real Estate for Phytoplankton

Activity 3:
Changing the Scene

National Standards
Science, English/Language Arts, Geography, Mathematics, Social Studies


>>Background Information
The Marine Environment

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