Beautifully Laminated Sediments from Lake Linne
Today was a whirlwind. By 7 am Lauren and I were calibrating new dissolved oxygen and pH sensors for the troll. 8 am meant making a lunch in between finding coring gear, bite of breakfast sandwich here, core tubing there. 9:28 we're hiking, frame pack on back, backpack on front. 11:00 cut fingerprint chunk off on aluminum boat rail burr…but 11:28, good ole' 11:28, we had mud. Svalbard tea, 10YR5/2 Gold…the Svalbard hillbillies have struck it rich…
Our packs and cores, waiting to show off our mud to the Svalbardkurset...
Yes, things moved fast and it is fast approaching too late (~11 pm) but with a glacier day tomorrow and presentations in the evening I did not want to get too far behind. Today, Mike and I initiated two new corers to the field and recovered laminated sediments from the floor of Lake Linne. I say laminated because that simply means that the cores show very finely layered sediments. What we specifically are most interested in are laminated sediments called varves that are light and dark couplets deposited yearly. The laminated sediments we took today came from more shore proximal zones that may have fine layers in them that are not from the simple annual sedimentary regime but rather from distinct events interbedded between the yearly progression (high rain events, underwater avalanches, etc…). Regardless, it was great to get my first look at the sediment from Linne and Helena and Dion to earn their wings.
I watch two, new to the world of coring, assemble the gear.
While it was a mostly calm day, the wind gave us a bit of turbulence and push downline that we had to deal with. This meant doing our best to throttle minor adjustments on the water and keep the lines from tangling or our boat from drifting away from the corer 20 m below the surface and half in the lake bottom. Sediment cores are usually most easily taken from the ice covered surface when you can lay everything out nice and neatly but as you've seen, that's not much of a possibility right now. One plus of the sediments here in the arctic as compared to those in temperate latitudes is that they are extremely stiff and easily handled. We were accordingly able to extrude the cores we weren't planning on keeping to get an immediate view of the results, something not usually possible in other environments. In places like Maine, the sediments on lake bottoms is typically an organic rich gyttja that is comprised of mainly diatomaceous remains (excuse the vulgarity but we refer to it as 'loon crap').
Dion and Helena splitting the core from the west side of Lake Linne
After extruding the core it was a simple feat to split it length-wise and clean with a swiss army knife parallel to the layering. What was then revealed were beautiful layers spanning back many, many years. It is kind of fun to think you can point to a layer and say, "I was born…then…"
A just-split core from Lake Linne
Later in the afternoon, the Svalbardkurset came by on their walking core led by Ole H. to learn about the REU and AG212 projects in the Linne Valley. Many of us gave overviews of our roles in the research taking place and we then extruded a core in front of the group. I was psyched to see a group so interested in the science and will gladly take any government/administrative official (state or federal) coring when I get back to Maine…must be able to lift 50 lbs of gear, have boat and motor, and hold a state fishing license (please send picture of boat and motor).
Svalbardkurset descends upon the north boat park
With that, good night folks and wish me luck making it to the glacier tomorrow for more water samples…it is going to rain…could be worse…wind…could be better…snow…