The Jokulhlaup

If there is one take-away from this Glaciology Summer School that I would want everyone to know (of those who hadn’t already known), it’s that glaciers themselves are a force of nature. Their presence can alter an environment, and their disappearance can affect the environment. We went on a different trek to the glacier front, led by Mike Loso of Alaska Pacific University Anchorage, and saw the glacier’s effects everywhere, from the rocky riverbed left behind as the glacier retreated, to the layers of the mountainside sloping down to the glacier bed below, to the white rock that had been scourged by the glacier…

Here is the Kennicott rive flowing towards us. The treeline/ridge is the terminal moraine (the accumulated soil at the edge of the glacier) during the last little ice age. The riverbank on the left is eroded most years by the annual Hidden Creek Lake flood, aka the “jokulhlaup”, (there’s a new word for most of us) and that boulder was still in that bank as of just a couple of years ago).

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Mike showed us this plant, called Dryas drummondii (in the photo is the plant’s seed head). The cool thing about this plant is that it is one of the early species to colonize newly un-glaciated terrain. And it’s a “nitrogen-fixing” plant, which means it takes atmospheric nitrogen and turns it into nutrients, which then benefits the soil for other plants.

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There may not be white in front of us, but there is a glacier. Here we are looking out at debris-covered glacier ice. This meltwater pond is next to where Kennicott River is coming out of the ice, and on the right is Bonanza Ridge, home to the old copper mines that used to dot this landscape.

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We climbed this beautiful glacier-scoured bedrock which lies near the toe of the Kennicott Glacier. The exposed sediment at the top among the trees is also glacier till (unsorted, unlayered sediment) that was deposited sometime during the last ice age.

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This tree has seen it all. This spruce stump, still in growth position, grew in front of the Kennicott Glacier in the late 1500s. It was overrun by advancing glacier ice in the 1600s, where it remained until the late 1900s, when it was exposed in this river channel as the Kennicott Glacier retreated. And it’s still here.

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2 Responses to The Jokulhlaup

  1. Lija says:

    Lindsay! So excited to following along with you on this adventure digitally after sharing your previous one with you on the other end. (Although I will be honest, I’d much rather be there beside you than behind my computer screen at work.) Of course being a nitrogen enthusiast, I just had to comment on this post! I will admit I don’t know much about terrestrial nitrogen-fixers, but in the ocean this task is fulfilled by tiny ‘bugs’ (not really bugs… just a pet name we scientists like to call microorganisms) called cyanobacteria, but only a few special kinds! Most marine nitrogen fixation happens in the nutrient poor ‘deserts’ of the ocean, which are around the tropics. In a way these regions are a lot like the newly unglaciated dirt I would imagine; no nutrients for other plants to use, so the special nitrogen fixers are able to work their magic, then allowing other plants (phytoplankton in the sea) to grow there as well–Another link between the tropics and the poles and a cool analogue between seemingly very different marine and terrestrial ecosystems. SCIENCE IS AWESOME! :D

    Say hi to the ice for me!
    ~Lija

    • lindsay says:

      HI Lija, so glad you are following digitally (of course it would be awesome if you wre here in person)! I was thinking about you actually when I learned about those nitrogen-fixing plants. And I love the connection you made between ice and the tropics. The ice said to say hello to you too!

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