Dropping anchor in Williams Bay early this morning, we awoke to a juvenile brown bear ambling across the intertidal shore, scavenging for mussels and other tidbits for its breakfast. After our healthy breakfast, we hiked through the mixed conifer/ alder forest along a bear trail likely travelled by the brown bear we sighted earlier.
Hiking through this humid, temperate rain forest, we re-discovered many of the plants we have learned about previously. Thick groves of sphagnum moss provided the opportunity to chat about Tlingit cultural use, as well as the development of peat in the short term and coal in a longer geologic setting. Short conversations addressed the necessity of consistent decomposition of organic matter to support the succession of recent forest growth to more mature forests. Towering hemlocks spurred short discussions of the impact of clear cutting and current plans of the Tongass National Forest Service to move toward more harvesting of younger growth trees and preservation of old growth trees. In a segway from peat to lichens, conversation ensued about the necessity of symbiotic relationships that led to cryptogrammic soils, likely the microbial ambassadors that potentially enable the transition of algae and plants from the ocean to the terrestrial sphere as plants developed roots both for stabilizing their erect growth, but also their absorption of nutrients. Symbiosis has likely been a major theme in species evolution and niche development. Other examples of symbiosis included the adaptation of mammals, such as red squirrels and bears, to create dens under tree roots. Brief discussions of herbivory ensued as we ambled through salmonberry, watermelon berry and twinberry patches near the forest seashore ecotone. Transition to kayaks and inflatable boat tours allowed folks to experience the marine biome.
Pulling anchor, we headed up Tracy Arm through the steep-walled, glacial cut granites and quartzite intrusions. Loading onto the inflatable boats, several groups ventured up toward the toe of the Sawyer Glacier. Pushing seaward by the mass of ice of the Stikine Ice-field, snow falling atop the ice-field may take between 200 and 500 years (depending on one’s information source) to reach the calving face of the ocean. We sat mesmerized in our expedition landing crafts safely watching tons of ice tumbles into Tracy Arm, sending swells of water toward our boats and slowly converting the geologic to glacial silt deposition. Conversations related to rates of glacier ablation as a function of climate change ensued, with guests learning that while glacial ablate (as they always have) the real testament of how quickly ice-field melts comes from research measuring annual shifts in snow accumulation as compared snow melt. The rate of glacial movement then becomes a function of snow converted to water that seeps to the base of the ice field and may or may not accelerate the migration of the ice field to the bay.
The evening concluded with a wonderful slideshow of guest photos of the week.
