Rotten Ice

Extreme summer melt: Assessing the habitability and physical structure of rotting first-year Arctic sea ice

The response of Arctic sea ice to a warming climate includes decreases in extent, lower ice concentration, and reduced ice thickness. Summer melt seasons are lengthening with earlier melt onsets and later autumn freezeups. We believe this will likely lead to an increase in so-called “rotten ice” in the Arctic at the end of summer. This ice has experienced a long summer of melt, is fragile, difficult to work with, and has received little attention. Comprehensive information on its physical and microbiological properties does not exist. Our team is embarking on an ambitious field campaign in order to study this poorly-understood type of sea ice in the context of its microstructural properties and potential for habitability.

This project has two main objectives:

  1. Determination of the physical and microbial characteristics and microstructural evolution of sea ice exposed to severe melt
  2. Exploration of the influence of biogenic particles such as sea ice algae, bacteria and polymer gels on the melting behavior of sea ice. This research will develop and apply state-of-the-art microbiological, molecular, biogeochemical and geophysical techniques to examine the character and evolution of natural Arctic sea ice at the end of the melt season at field sites near Barrow, Alaska.

This project will assess:

  1. Ice physical characteristics (ice density, salinity, permeability, albedo, and microstructure) using standard and novel microscopy and X-ray computed tomography techniques
  2. Ice algal and bacterial characteristics (abundance, activity, biomass, productivity and diversity) using epifluorescence and confocal microscopy, flow cytometry and massively parallel taq sequencing techniques
  3. Polymer gel characteristics (abundance, composition, gel carbon biomass, and size) using in situ microscopy, flow cytometry and confocal microscopy techniques
  4. The relationship between biogenic particles and ice physical characteristics, in particular microstructural properties for melted and intact ice samples using image analysis and correlative statistical methods.


The Team

Karen Junge
Project PI
Bio coming soon!
Bonnie Light
Principal Physicist
Bio & Interview
Monica Orellana
Biological Oceanographer
Bio coming soon!
Carie Frantz
Bio & Interview
Shelly Carpenter
Micro/Molecular Biologist
Bio & Interview



The wonderful APL outreach folks have produced some videos about us and our work, check them out! Link to APL YouTube Channel

May: Just after our first group trip to Barrow, the team discusses our goals for the project.July: 2015 field season complete, we share our impressions of rotten ice and talk about all of the lab work that will be keeping us busy in the coming months.
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Field Reports

  • June 1: Back to Barrow

    We’re back! We had a busy two weeks at home in Seattle spent catching up on the rest of life and processing as much as we could from our May expedition in order to stay ahead of the game and, critically, to try to identify problems early so that we can correct them in June and July. Shelly has been busy with the several dozen cell counts she came home with (Spoiler: there are lots of cells in the ice!) and ordering stuff that we either ran out of, forgot to bring, or didn’t realize that we needed. I’ve been…

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  • May 13: Farewell Feasts and Whalemeat

    On one of our last days, the lab staff invited us to a muktuk feast, which they had prepared from whale meat that Scotty, the lab mechanic, had from being part of a whaling crew. After a prayer of thanks, they told us what was what: first, traditional frozen, raw muktuk from the previous season: about an inch-thick piece of whale skin and blubber; second, a cooked version of the same from fresh meat from the whale just caught; third, steaks of whale tongue. We were given seasoning mix to flavor it, a traditional rounded ulu knife to cut it,…

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  • May 11: Back in the Lab

    For me, back to the lab meant back to the walk-in freezer. Things went well all morning, but when we started back up after our cafeteria lunch (which included more of the fudge-like chocolate cake to which several of the team had become hopelessly addicted and which Bonnie described as “regrettably good”), things started to go south.As one particularly-beautiful-looking thin section was nearing completion, a spider crack suddenly formed halfway through a scrape and the whole thing fell apart. I sawed off a new piece and tried again, but again once the sample was close to completion, it cracked and…

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  • May 9: Elson Lagoon

    After all the time cooped up working hard in the lab, another field day was a literal breath of fresh air. But first we had to wait over an hour for our bear guard, who had slept through his alarm because he was out partying the night before because a large female bowhead whale had been caught by one of the local native whaling crews. We passed the time by packing up the sled, telling field stories, and taking increasingly silly photos.We were so anxious to get out on the ice when he finally did arrive, that we didn’t discuss…

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  • May 8: Optics Day 1

    Bonnie and I went out today to do some optics measurements at a location close to the sampling site on the Chukchi Sea. We also recruited the BARC Senior Scientist, Karl Newyear, to help us out.Bonnie wanted to measure the following: the relative amount of sunlight reflected by the snow (albedo), the relative amount of sunlight transmitted through the snow and ice at the bottom of the sea ice (light transmittance), and the amount of sunlight that passes through the snow and ice at regular intervals down a core hole (vertical light profile).In the photo above, you can see the spectrophotometer…

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  • May 7: Lab Time

    Field days are what we all look forward to most, but most of our time in Barrow (and in general) is necessarily spent in the lab. Cores and other samples acquired the day before on the Chukchi Sea, it was time to buckle down and process everything. We had been in the lab until almost 2 am the night before, but there was still much to be done, and we scattered into the lab and various walk-in freezers and coldrooms.It all starts in the walk-in freezer, which I had set to -15°C, nice and frozen, with the fans blowing cold…

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  • May 6: Chukchi Sea Sampling Day

    As we begin Day 7 of our trip up here to Barrow, Carie has officially declared that “Super Fantastic Science Has Happened!”While Carie is busy in the cold room chopping up ice cores, microtoming them into thin sections and inspecting them under the microscope, keeping meticulous notes, setting up cell incubations, consulting with the PIs, videotaping the team for science outreach, singing songs to stay warm, etc. she has had barely any time to keep up with the blog. Well, almost no time. As you’ll see shortly, her thoughts are interspersed throughout this post as well. Until Carie can fully take…

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  • May 5: Settling In

    We spent all day today unpacking our three pallets of coolers and boxes and cases, setting up the lab, and getting everything prepared for our first day out on the ice and the experiments after that. Carie was relieved that the fancy and expensive microscope seemed none the worse for the wear after its long trip up here and that the little sensor spots she had last-minute shipped from Germany made it in on time. Monica and Karen spent the day gluing said sensor spots into little glass vials while Shelly and Julianne tag-teamed getting the whole mess sorted into…

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  • May 4: Barrow Bound!

    It’s been a year of planning and preparation, ordering and organizing, testing and troubleshooting, but today we’re finally off to the Arctic!We’re all feeling pretty excited to be headed North to the ice. Shelly just got back from fieldwork in Greenland little over a month ago, but she’s buzzing and anxious about this busy trip (“Gaaaah just board the flight already!! How can people be sitting? Let’s GO!”). This is Karen’s first trip to Barrow since 2001 and she’s beaming like a kid. Bonnie is toting a shiny new spectrometer that arrived Friday after quite a bit of “is it…

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