Glacier talks!

, 5 min, 895 words

Tags: alaska how-stuff-works kayak-adventures

Before I can start getting checked out as a guide, I need to pitch five tarps, practice my "beach speech" five times, and try out five glacier talks. I discussed these glacier talks a little while ago in the context of thematic interpretation. I need to be prepared to give two different "glacier talks." The first is an introduction to glaciers, and the second is elaborating on that to feed into a theme. Imagine that I'm delivering these out on the water, in nearby Aialik Bay.

Glacier 101

Welcome to the glacier, folks! This glacier, like its brethren, is a giant river of ice plowing its way through this landscape. Just like a river, it flows downhill, driven by gravity down the path of least resistance.

Like a tree or a river or a bear, Aialik Glacier has natural cycles in its life. Just like a bear, Aialik has things it needs to thrive. A bear needs food, and Aialik needs to be fed by the Harding Icefield. The cool thing about tidewater glaciers is that a very healthy part of their life cycle is calving. Calving is when a glacier drops big chunks of ice into the ocean, which is what we're paddling through right now. When Aialik gets fed well by a lot of snowfall, it calves more. When it's hungry, that calving might decrease a bit.

Speaking of ice, let's talk briefly about the color of this amazing ice. Glacial ice starts as snowfall, way up on the Harding Icefield. Over several years, snow piles on top of snow and compacts the lower layers, eventually squeezing out air and producing denser and denser ice. After around ten years, this compresses almost all the air out of it, leaving just dense ice. And just like when you have a lot of water, when you have a lot of this very dense ice, it appears blue to us.

I should point out that we are really lucky to have tidewater glaciers here. If we were further south, it would be too warm for glaciers to reach the ocean. That's why there are no tidewater glaciers in the lower 48. If we were further north, it would be too dry to accumulate this much ice in one place, and once again the glacier wouldn't reach the sea. Right here we are in a happy medium, in the northernmost part of the largest coastal rainforest in the world.

If people are still excited about glaciers, I'd talk about advance and retreat here too. For now I'm skipping it, because it's a little harder to explain in the context of tidewater glaciers.

Glaciers: dynamic forces of nature that shape everything in this area

Glaciers shape everything around us, both past and present. A few things I particularly like:

  • The landscape here was carved by glaciers thousands of years ago. Once upon a time, Aialik glacier extended all the way down this bay. Because glaciers pick up rocks and silt as they move, they act as sandpaper, carving out the areas they pass through. For one thing, this helps explain why Aialik Bay is so deep – about 700 feet in some places, while it's only a few miles wide. For another, it explains the rounding of many islands here. Slate Island, for instance, was once under the glacier entirely, which rounded out hard edges and left us with the island we know and love. Finally, all those tiny semicircular bays we passed were once cirque glaciers, like the ones we saw on our journey out of Resurrection Bay.
  • One key thing Aialik Glacier contributes here is minerals. The rock around here is rich in iron, so glacial silt is as well. Iron is really important for your body's function – that's how your blood carries oxygen! It turns out that it's also crucial for the health of marine ecosystems. Many places in the ocean have all the nutrients they need for life, but if they're missing iron, they'll just be ocean deserts. Here, with a steady influx of iron from calving glaciers, we have all the ingredients we need for massive phytoplankton blooms. Phytoplankton are a little like tiny single-cell sea plants, and while you can't see them with your naked eye, you can see the swirls of phytoplankton we have here from space. That wealth of phytoplankton feeds a mass of zooplankton (tiny single-cell sea animals), which in turn feed a mass of krill. Krill feed fish. Fish feed marine mammals: whales, seals, sea lions...the list goes on and on. It's thanks to glaciers that this area is one of the most productive marine ecosystems in the world.
  • We've talked a little about how glaciers carved the landscape here. One thing I find fascinating is how this affected Native peoples as well. Because this area has such inhospitable and impassable terrain, travel by sea was really important. Among other factors, this is why kayaks were such a crucial part of Sugpiaq culture around here.

Practice practice practice

At this point I feel pretty good about my ability to offer interpretation about glaciers past the introduction. But my glacier 101 is noticeably shaky, so it's nice to have it written down somewhere! Over the next days, weeks, and months I will continue to practice and hone these general outlines.