Glacier Bay National Park and Preserve
As the Sea Lion sails deep into Glacier Bay, we rewind time toward the ice ages. Ocean water gives way to tidewater glacier, and rainforest fades to sparse vegetation and ultimately bare rock. With the fastest documented retreat of glaciers in the world, here we can fathom the processes that introduce life after iciness.
A time-lapse moving image might come to mind as we ponder the processes of glaciation, natural succession, and climate change. Clouds sweeping overhead quickly dump snow on mountains; icy swaths forming and sliding rapidly downhill, sculpting out valleys, dragging fragments of mountains with them. As Earth swings out around the sun on a changing ellipse, wobbling as it goes, shifting its tilt, the amount of incoming radiation received varies, affecting ice cover, sea level and climate. Successive ice ages and interglacial periods rhythmically cycle.
During warm stretches, glaciers form more slowly and their termini retreat counter-intuitively uphill (although individual ice molecules always ride gravity down). New land is exposed and pioneering botanical organisms creep in laying foundation for temperate rainforest. Floated in as seed or spore, lichen, moss, alder, willow, cottonwood, spruce and hemlock rise up in sequence, photosynthesizing energy as they clamber for real estate, light, nutrients and water.
Oceanic waters flood in behind the retreating ice, filling new fjords, and carrying colonizing tidal invertebrates, a prodigious variety of fish species and various marine lifeforms. Mammals expand their ranges into now newly exposed landforms, rainforests and marine habitats.
Today we enjoyed viewing a brown bear foraging at the beach, mountain goats on steep cliffs, sea otters floating on their backs, puffins flying about their nesting burrows, humpback whales breaching—all active creatures that have swept into this national park as retreating ice has created new opportunities on land and sea.
While most glaciers are retreating, some like the Grand Pacific we saw today are in advance, suggesting the continuing cycles of ice, land, and life that spin through the millennia. In this pristine protected place, the processes of time—climatic, geologic, biologic, astronomic—on scales beyond our normal perceptions, are here before us to appreciate.
As the Sea Lion sails deep into Glacier Bay, we rewind time toward the ice ages. Ocean water gives way to tidewater glacier, and rainforest fades to sparse vegetation and ultimately bare rock. With the fastest documented retreat of glaciers in the world, here we can fathom the processes that introduce life after iciness.
A time-lapse moving image might come to mind as we ponder the processes of glaciation, natural succession, and climate change. Clouds sweeping overhead quickly dump snow on mountains; icy swaths forming and sliding rapidly downhill, sculpting out valleys, dragging fragments of mountains with them. As Earth swings out around the sun on a changing ellipse, wobbling as it goes, shifting its tilt, the amount of incoming radiation received varies, affecting ice cover, sea level and climate. Successive ice ages and interglacial periods rhythmically cycle.
During warm stretches, glaciers form more slowly and their termini retreat counter-intuitively uphill (although individual ice molecules always ride gravity down). New land is exposed and pioneering botanical organisms creep in laying foundation for temperate rainforest. Floated in as seed or spore, lichen, moss, alder, willow, cottonwood, spruce and hemlock rise up in sequence, photosynthesizing energy as they clamber for real estate, light, nutrients and water.
Oceanic waters flood in behind the retreating ice, filling new fjords, and carrying colonizing tidal invertebrates, a prodigious variety of fish species and various marine lifeforms. Mammals expand their ranges into now newly exposed landforms, rainforests and marine habitats.
Today we enjoyed viewing a brown bear foraging at the beach, mountain goats on steep cliffs, sea otters floating on their backs, puffins flying about their nesting burrows, humpback whales breaching—all active creatures that have swept into this national park as retreating ice has created new opportunities on land and sea.
While most glaciers are retreating, some like the Grand Pacific we saw today are in advance, suggesting the continuing cycles of ice, land, and life that spin through the millennia. In this pristine protected place, the processes of time—climatic, geologic, biologic, astronomic—on scales beyond our normal perceptions, are here before us to appreciate.
