It’s the time of year for soil science

Maud van Souest, PhD student at Loughborough University studying the effects of dust deposition on soil development reports from the field.

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And we are back! Halfway through the third and last field visit of the project’s first year. The group is a bit bigger this time with seven people focused on different parts of the project. Keechy Akkerman, Clay Prater, Adam Heathcote, Tom Mockford and Rebecca McKenzie set foot on the Greenlandic soil for the first time. John Anderson is, of course, the veteran of the group (it’s his 22nd field season in Greenland) and Maud van Soest is well on her way.

Today, our main task of was to move all the scientific, and less scientific equipment, that is stored here at KISS to another building (also known as moving all of John’s junk, according to Adam). The weather was supposed to be very bad, but I think that we could all use a little break of from the long days in the field. It is, however, impressive that we were able to take a break relatively early in the week. We have only one lake left to sample, most of the dust traps are reset and many kilos of soils have been collected. Clay is doing a good job in the lab trying to work out the enzyme experiment and processing the water samples that come back from the field.

One of the biggest problems that we encountered is a bacterial reaction in the dust traps that makes the filtering of the sediments very difficult. A different kind of dust traps (BSNE) is installed to measure the vertical dust flux to be compared with the horizontal deposition. This will allow us to distinguish local reworking from actual dust storms. Last but not least, Tom has worked on installing DustTraks that will be deployed in April next year that measure dust concentration in the air.

Keechy has been taking multiple sediment cores, rock scrapings and aquatic plants for her PhD project in order to get a grip on the spatial variability of primary productivity within the lake. Our visitor Adam was so kind to sit in the boat for at least an hour without a break to make a high resolution bathymetry using a GPS coupled to a SONAR. The last lake we visited, SS1590, was especially interesting in this respect with a complex bathymetry and large lake-level variability, which was observable from the retreated shore line and could be traced back in the long sediment core that Keechy analysed before the fieldwork started.

This field visit is the most important for the soil part of Maud’s PhD, as the active layer of the soils around Kangerlussuaq are only defrosted for a very brief time, and this is the sampling window!. She has been describing the variety of the soils in the 4 lake catchments with dust traps and on the ridge in order to make some soil maps of these areas. She will analyse some of the profiles in more detail in the laboratory over winter.

One more week to go in which we will finish sampling, doing our analysis in the lab and leave everything ready to go for the next field visit in April 2018!

 

 

 

 

Sampling in the sun

The Dusty team returned to Greenland in June, once the ice on the lakes had melted. What a difference 6 weeks makes. This is a beautiful time of year in Kangerlussuaq, with clear blue skies and warm sun, which made for some stunning hikes out to the sites among the flowers which were in bloom.

Here is a video of the view across lake SS17b  where we were transporting equipment across towards the next site.

The main aims of this trip were to sample waters from a number of lakes across a transect of dust deposition leading away from the ice sheet to monitor the associated patterns of water chemistry and enzyme activity.  Chris also set sediment traps to capture particulates as they settle in the lakes.

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We found an especially nice surprise at a new site elegantly named SS17c which had stunning views down the outwash plain, and from which we could see the wind blowing dust up onto the surrounding higher land.

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For this trip we had to set up the chemistry lab once more, for analysis of a range of macronutrients and for the enzyme assays. Some long lab days lay ahead, on top of the fieldwork.

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We also set up a leaching experiment to determine the release rates of nutrients and other elements from the dust. A dusty job weighing out the aliquots to spike the experiment with!

This was a long day’s work- finishing at 3am, and because we had to sample at 12 hour periods afterwards, Amanda volunteered to do the shift work for the next few days while the rest of the team finished off the field work. The experiment is now doing it’s thing in the growth chamber…

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Maud was also in charge of emptying the dust traps which were set on the April trip which will be used to monitor dust deposition.

P1070045Meanwhile, back on the lake, we were sampling the benthos which grow on the bottom of the lake, using core samplers to capture the massive variability in habitats on the bottom of the lakes. Here are some Nostoc spp, a cyanobacteria which grows in very large balls on the bottom of the lake, together with charophytes.

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Added to this, we also using ‘Dusty Cam’ to explore the bottom habitats in the lakes.

The team will be back in August to look at revisit the lakes