The Barrow Arctic Research Center lab. Photo by Carie
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 wind hard down my neck as I took cores we had collected from the field and used a chop saw we had hauled up with us to cut the samples into manageable chunks (but not before sterilizing the blade—we were interested in pristine in-ice biology after all). Some of those chunks, cut into 10 cm pieces, were then handed off to Karen and Mónica, who weighed them and then tried to set them up in a centrifuge retrofitted to handle large chunks of ice so that we could spin them and extract what brine we could from the inside of the ice.
Two of the walk-in coldrooms where much of the lab work took place. Photos by Julianne
Arctic sea ice forms when the sea freezes. Since seawater is salty, it freezes at lower temperatures than freshwater freezes. As water freezes out, the salt that makes seawater salty gets concentrated into increasingly saline fluids called brines that form little pockets and channels of salty liquid inside the solid ice. In these liquid oases within ice, living organisms can survive and even remain active at temperatures well below the freezing point (e.g.,
Junge et al. 2004). As part of this project, we want to see how the microbial communities within ice change as the ice “rots” as summer progresses, and wanted to see the difference between the microbes in these brines versus those frozen into the ice. The only way to get the brines out of cold, winter ice is to centrifuge it—spin it at really high speeds—and hope some of it comes out of the ice.
Centrifuges are things to be handled with great respect. Centrifuge samples need to be perfectly balanced…an unbalanced centrifuge is a bomb capable of hurling a large and heavy metal projectile at terrifying speeds out into the room. Most (including the one we were using in Barrow) have safety mechanisms and will refuse to ramp up to high speeds if they are improperly balanced, but imbalance can still damage them, and they are expensive and invaluable pieces of equipment. So balance them they did, with all means available, down to adding small strips of lab tape to the outsides of the bottles to get down to sub-gram accuracy. Still, some of the samples were difficult beasts with weak layers and multiple chunks that made balancing—not just of the mass but of the load distribution—a challenge that kept Karen and Mónica busy for a solid and frustrating day and a half.
Monica and Karen weighing and balancing ice samples for centrifugation. Photo by Julianne
Once the samples were finally spun, both the spun out brine (sometimes as little as just a few milliliters from the large chunks of ice, one of the reasons we had collected so many cores the day prior) and the remaining brine-depleted ice were handed off to Shelly for further processing. Shelly had during all this been hanging out in a small cold lab set at 5°C. She was bundled up in a wool hat, puffy jacket, warm pants, boots, and fingerless gloves as she took samples handed to her, melted the ice (into saltwater to keep the organisms inside from getting too shocked by the transition from brine to much fresher meltwater) inside giant sterile bags, and aliquoted it out into the dozens of different measurements we’d be doing back in Seattle: cell counts and species identifications, analysis of carbon in its many forms, presence of nutrients, polymer sizes and types and concentrations, and experiments to measure microbial activity. She also pumped the liquids through filters of various sizes to collect and measure chlorophyll, particles, and to collect samples for DNA and RNA analyses. The samples were put into all of their hundreds of different special bottles with their hundreds of pre-printed sample labels, poisons and fixatives were added and the vials capped and sealed to make sure the microbes didn’t throw parties in them before we could analyze them, and they were stored in their various places—boxes, freezers, refrigerators, and deep-freezers for shipment and analysis back home. As inevitable volume shortages or excesses popped up, impromptu meetings were called to discuss measurement priorities which always involved a discussion not only of scientific importance, but also of cost, likelihood of success, and whether or not we had brought enough bottles.
Meanwhile, Bonnie and Julianne were back out on the ice with a sled full of light meters of various kinds and purposes for “field optics day”, which hopefully one of them will chime in on in a separate post since I wasn’t there to report on what went on. While they were outside enjoying a nice Arctic day, we were all freezing our butts off in lab.
As the freezers and fridges and boxes of samples filled up, I was still in the -15°C room. In addition to the samples for chemical and biological measurements, we had ambitious microscopy goals, and I was making microscope slides of different parts of the ice so we could look at microstructure, microorganisms, polymers, and the spatial relationships between those things. The first step was cutting little cm-thick hockey pucks of ice from different parts of interest in the core. I made both horizontal slices—little round pucks because of the round ice cores pockmarked with brine pockets—and rectangular vertical slices that showed the long strings of brine channels. Those pucks were smoothed on the bottom and glued—using clean freshwater which froze almost instantly in the cold—onto glass plates. It was then a long process of painstakingly shaving 10- to 40-micron-thin slivers of ice off of the tops of the pucks using a very sharp knife blade on a microtome to get the pucks shaved down to a glass-smooth piece of mm-thin ice glued onto that glass plate. Shaving down each slide was a labor of love that took anywhere from 20 minutes to over an hour depending on the thickness and evenness of the puck and how prone to breaking it was. Often, the shaved ice pieces would be almost thin enough to use on the microscope when they’d suddenly crack open and break to pieces, and I’d have to start over. I spent an entire day in down pants, winter boots, layers of jackets and hats, and thick gloves (when I could use them—much of the work required bare or lab-gloved hands) shaving ice with a razor in a dimly-lit -15°C room. But getting a nice thin section was incredibly satisfying—each time I got one without it breaking I felt like I’d produced a masterpiece. They were beautiful, and it was really exciting seeing the fine structure of the ice crystals and brine pockets and channels like I’d only seen it in textbooks and papers before.
Carie preparing thin sections on the microtome in the -15°C walk-in freezer. Photo by Shelly
Once the thin sections were prepared, the microscopy work could begin, and the -15°C room (kept that way to make it possible to do the precision shaving of the ice to prepare the thin sections) was warmed to a balmy -5°C that would allow us to see the ice at
in situ temperatures (i.e., the temperature we had found the ice at). As the room warmed, you could watch brine channels opening up and expanding in the slides, which is what they do as ice warms in nature. The goal was to do a thorough analysis of thin sections of each horizon of the ice and look at the layout and structure of the ice under transmitted light, crystal structure and orientation under cross-polarized light, look for chlorophyll-containing algae by their red autofluorescence, and look for other organisms and microbial slime using fluorescent stains. All of this proved frustrating because of the presence of a whole lot of unidentified “stuff”—maybe salt precipitates, sediment, lint blown around the coldroom, or who knows what else—in our samples as well as problems with the stains not being as specific as we had thought they should be and debates about what was what between Karen, the ice bacteria expert, and Mónica, the algae and polymer expert. Still, we got some beautiful images and hope eventually to figure out what it all means.
Karen and Julianne at the microscope, bundled up in parkas to survive the cold while they worked in the walk-in freezer. Photo by Carie
All of us took periodic breaks from the demands of walk-in-freezer work to do things like measure salinity, pH, and density of our ice horizons; take reads of photosynthetic efficiency in ice and filtered samples; and compile, type up, and organize all of our field notes and photos. We also all tried to squeeze in moments to keep somewhat caught up with the demands of normal life—emails from colleagues and students and journal editors (most of which were met with “In the Arctic, will respond when I return” autoresponses) as well as loved ones. Our ten days in Barrow for this May trip were relatively short by arctic field standards, but that’s still a long time to leave family and children behind. As Karen skyped on a spotty internet connection with her husband and kids, giving them a walking tour of the lab on her tablet, Bonnie told us stories of creative ways she stayed connected with her kids while out on even longer expeditions, including an elaborate, pirate-themed scavenger hunt with emailed clues.
For me, it wasn’t as much being away from people that was hard, but being with people 24/7. We worked together, ate together, went to and from the lab together, roomed together. The only alone time we had were bathroom breaks (one of the lab bathrooms was really warm, so several of us took regular long bathroom breaks whether we needed a bathroom or not to thaw out). That combined with the long work hours (we were regularly in the lab until after 10pm—which in 24 hour daylight was easy to do), misbehaving instruments, exploding experiments (don’t ask, I’m still upset about it) and confusing results, the WHOMPing of the water pump back at our hut which had left some of us (me especially) sleep-deprived and cranky, and nerves started to get short. Some discussions started to border on arguments, there were some “I’m going for a walk and I don’t want anyone to follow me” moments, and some minutes spent staring at the wall and breathing deeply to keep from throwing an instrument across the room. I mean, I won’t speak for everyone, but I certainly had a few of those moments.
Carie, taking a break from the world. Photo by Julianne
However, our team has a lot of shared respect and affection and that made a world of difference in keeping the wheels of this project turning. Everyone has a role and a long pile of tasks, everyone brings necessary expertise and knowledge to the table, and everyone is needed here. We also all really like each other and work well together, so despite short nerves, we continued sciencing without fights or dramatic meltdowns. Some of the lab staff commented that they’d never seen a group seem so harmonious and happy working together as we were. One of them attributed it to us being an all-woman team, which was an interesting hypothesis. Before I started this project I had people—men and women—warn me that all-woman groups would be catty, competitive, passive-aggressive, too emotional to get things done, and all sorts of other negative stereotypes that were quite the opposite of reality. This was the smoothest field effort I’ve ever been part of! Whatever the cause of our general success, I was grateful for Shelly’s humor, Karen’s warmth, Mónica’s enthusiasm, Bonnie’s even keel, Julianne’s positivity, and everyone’s dedication and hard work (and the laughs—the laughs were key!). It’s a lot easier to keep motivated when everyone else is, too!
-Carie
Monica is excited to see algae in our Chukchi Sea samples | 
Diatoms from Chukchi Sea ice as viewed under the microscope |
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