We will take NPK (nitrogen, phosphorous, potassium) data from the
Sólheimajökull soil samples and sequence the DNA extracted from those
samples using both Nanopore MinION and the traditional 16s rRNA technologies
to quantify the soil’s development. Information from these tests will facilitate
more accurate sampling and data collection methods for future trips. The
sequencing data will tell us how microbial populations evolve as the glacier
recedes and soil conditions change.
Digging for DNA at a Receding Icelandic Glacier
Acknowledgements: Gummi Magnússon, Skálanes
(Ólafur Pétursson, Rannveig Þórhallsdóttir, Freyr),
Icelandic Field Studies 2017
Mapping Sólheimajökull
What Next?
Glaciers around the world are retreating at an accelerating rate as a result of global climate change. As the ice melts and exposes more land, bacterial populations in the soil
change in response to their new environment. We are exploring microbial population changes at the Mýrdalsjökull glacial offshoot Sólheimajökull in Iceland. We hope to learn
how microbial populations are shifting as the glacier retreats. Soil samples were taken at fourteen different sites in May of 2017. Collected at different end moraines, the
samples represent a range of time frames of exposed soil (determined with Quantum Geographic Information System (QGIS) software). We used DNEasy kits to extract DNA
from each soil sample. Unfortunately, we were only able to extract usable DNA from 5 samples. Our next steps include 16s rRNA sequencing and whole genome sequencing to
identify what microbial species are present at each site. We will visit this site in future years to collect more samples and grow our database.
Sampling at Sólheimajökull
● Georeference maps using QGIS from 1960, 2010 and 2015 to
understand glacial retreat throughout history
● Determine coordinates for dirt extraction and sampling sites at
different end moraines
● Go to the sites when physically possible (some were too steep
and dangerous to reach on foot)
● Gather data at each location
○ Take a photo of the site and import into our FieldDay platform
○ Collect data on temperature and elevation
○ Withdraw dirt from three points at each site using a core with
preference to spots with signs of life nearby
● Test nitrogen, phosphorous and potassium (NPK) levels in each
sample
● Extract microbial DNA from each sample using a DNEasy
PowerSoil kit (MoBio) for downstream sequencing
Method
Using QGIS we overlaid several
maps from different eras. By
examining the location of the glacier
over a period of 50 years, and
reading several accounts we used
the QGIS system to determine the
latitude and longitude of several
points selected for approximate
length of time exposed from the ice.
After studying the samples we went
back to QGIS and updated the map
with the quality of the sample site.
Cait Conley, ‘19; Andrew Fishback, ‘19; Daniel Stoffregen, ‘19; Emi Smith, Assistant Professor of Biology
Figure 1: Team Dirt collecting samples at Sólheimajökull. Our teams braved dangerous slopes of scree and some very windy
conditions to collect our samples. We were not able to collect all of the originally planned samples due to conditions on the ground. We
took alternate samples to replace those we could not physically access. Large image: Sólheimajökull glacier with a team on top of a
high point collecting a sample. Inset image: Sampling team at work collecting soil and location data.
Figure 2: QGIS image of sampling locations. Each dot
represents a location where a sample was collected. Colors
of each spot indicate quality of DNA extraction. Landscape
image of the glacier’s snout provided by our drone.
Site
Number
Sample Site Coordinates
Latitude Longitude
DNA
quality
Date Site
Became
Exposed
1 n/a n/a -
2 63.5336 -19.3435 none 2014
3 63.5311111 -19.3669444 poor 2003
4 n/a n/a -
5 n/a n/a -
6 63.53361 -19.34444 poor 2012
7 63.53167 -19.34528 ok 1997
8 63.53056 -19.34778 none 1935
9 63.529507 -19.34778 ok 1908
10 63.5322222 -19.3569445 ok 1933
11 63.53328 -19.3466 none 2011
12 63.53273 -19.34704 none 2009
13 63.53432 -19.35766 none 2005
14 63.5322417 -19.325322 none 1500
Table 1. Coordinates of soil samples and quality of
DNA extracted from each site.
Figure 3: DNA extracted
from Sólheimajökull
samples. Three DNA
extractions were collected
from each sample and run on
a 0.8% agarose gel with a
1 kb DNA ladder (NEB).
