Candidate number: 001837 -0030
INTERNAL ASSESSMENT
Geography HL
Fieldwork question:
What was the impact of the retreat of the moterasch glacier?
Word count:
2432
Session:
May 2023
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Candidate number: 001837 -0030
Criteria A - Introduction 2
Aim: 2
Geographic context: 2
Reasons for glacial retreat: 2
Figure 1: Map of Switzerland Figure 2: Model of Morteratsch glacier (where the
data was collected) 2
Hypothesis 1: 3
Hypothesis 3: 3
Figure 4: Drawn topographic map of Morteratsch glacier 3
Criteria B 4
Figure 5: Distance from previous group (m) 7
Figure 6: DIstance from river (m) 7
Figure 7: Measuring ground wind speed, and air temperature 7
Figure 8: Soil depth diagram: soil probe inserted in saturated soil, until bedrock
blocks it 7
Figure 9: Inserting probe and identifying percentage of vegetation 8
Figure 10: Measuring soil depth with ruler 8
Criteria C and D 9
Hypothesis 1 9
Figure 11: *scatter represents the large raw data + identifies anomalies 9
Table 1: 9
Table 2: Spearman's rank 10
Table 3: Rs result for correlation between soil depth and percentage of vegetation
coverage 10
Figure 14: *bar graph clean visual representation of the quantitative data 11
Normals 11
Anomalie 11
Hypothesis 2 13
Figure 19: *Bar graph compares the raw quantitative data 13
Normals 13
Anomalies 14
Hypothesis 3 14
Normals 15
Figure 25:*Visualisation of figure 24 scenario 16
Normals 16
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Criteria E 17
Criteria F 18
Strength: 18
Weakness + Improvement: 18
Extension of the investigation: 18
Works cited 19
Word count 2432
Criteria A - Introduction
Aim:
To investigate the impact of the Morteratsch glacier’s retreat on its surroundings; vegetation, air
temp, humidity, ground wind speed, soil depth and how this correlates to climate change.
Geographic context:
The Morteratsch glacier located in Pontresina, Switzerland is the largest
glacier by area in the eastern Alps. Conradin Burga, was the first to
analyse Morteratsch's vegetation dynamics over 20 years, this map
corresponds to his research from 1857 to 1997 and demonstrates
convincing evidence of the glacial retreat due to climate change.
Reasons for glacial retreat:
On a global scale, increases in greenhouse gases are the main cause for
glacial retreats, and on a local or regional scale, changes in the Earth’s
orbit around the sun and the ocean heat distribution also contribute to
the retreat.
This glacier is untouched and suitable for raw data collection. To take
full advantage of its natural state, data was collected 10m away and
along the proglacial river Ova da Bernina, at the base of the U shaped
valley up until the glacial cirque at the head of the valley.
In correlation to the IB syllabus this topic comes from The
characteristics of extreme environments (option C) - changing
distribution of extreme environments over time, including the advance and retreat of glaciers and
natural desertification.
Figure 1: Map of Switzerland Figure 2: Model of Morteratsch glacier (where
the data was collected)
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Hypothesis 1:
There is a positive correlation between soil depth and vegetation coverage. Multiple variables affect
this, such as floodplains, solar energy (required for photosynthesis) and escarpments where water
runs down where the risk of soil erosion (icefall, rocks, gushing water) is greater.
Hypothesis 2:
As ground wind speed increases the percentage of vegetation coverage decreases. Wind can remove
soil particles, causing soil to erode and hinder growth of vegetation. In addition, freeze damage
caused by cold wind strips moisture from plants resulting in dehydration and damage to cell walls.
Hypothesis 3:
There is a positive correlation between soil depth and distance from the glacier snout.
Considering that the Morteratsch glacier is retreating due to ablation, new land then has longer to
develop sufficient substrate depth for vegetation than the glaciated land before it.
Figure 4: Drawn topographic map of Morteratsch glacier
Criteria B
The 50 sites were chosen as they gave a wide range of accessible data that could
communicate a correlation between the distance from the glacier snout and the variables;
soil depth, vegetation coverage, ground wind speed. This is also beneficial when anomalies
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occur, as there is enough backup data to still provide an identifiable relationship between the
data. With the use of Spearman’s Rank (which identifies a correlation between rank and not
the actual value), we can give a degree of statistical accuracy with ‘Rs’ when there is not an
obvious correlation.
Measuring tools Sampling strategy Why was this used: Hypothesis
Holding the kestrel 3000 close to the Correlates to hyp 2:
ground to measure ground wind speed. ● Easy to read
● Reusable
Using the tip of the probe to measure soil Hyp 1,3:
depth ● Reusable
● Sharp edge - easy to
insert into soil
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Measure the soil depth from the mark on Hyp 1,3
the soil probe ● Easy to read
● Reusable
Distance: To accurately measure 20m Hyp 1,2,3
away from the previous group. ● Long enough to measure
20m
- control variable, ensuring data ● Flexible - place over
collection is accurate large debris
String 10m string was used to measure the Hyp 1,2,3
distance from the river ● Easy to hold close to
river + flexible
- control variable, ensuring data ● Constant 10 m
collection is credible
Used to sample soil depth and % Hyp 1,2,3
vegetation: ● Reusable
Insert soil probe into 4 different quadrants ● Sturdy
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Measure longitude and latitude Location awareness
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Figure 5: Distance from previous group (m)
Figure 6: DIstance from river (m)
Figure 7: Measuring ground wind
speed, and air temperature
Figure 8: Soil depth diagram: soil probe inserted in
saturated soil, until bedrock blocks it
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Figure 9: Inserting probe and identifying
percentage of vegetation
Figure 10: Measuring soil depth with ruler
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Criteria C and D
Hypothesis 1
There is a positive correlation between soil depth and vegetation coverage. Multiple variables affect
this, such as floodplains, solar energy (required for photosynthesis) and escarpments where water
runs down where the risk of soil erosion (icefall, rocks, gushing water) is greater.
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Figure 11: *scatter represents the large raw data + identifies anomalies
Graph showing no significant correlation between the 50 points of the percentage of vegetation (%)
and soil depth (cm), as the trend line is relatively straight.
To see if there is a more significant correlation, the average must be taken from every 4 points from
both the percentage of vegetation and soil depth for all 50 points. This will ensure 100m intervals of
data which might draw out some anomalies.
Table 1:
Average:
(a1+a2+a3+a4) ÷ 4
Table 2: Spearman's rank
Figure 12: How to calculate Rs
Figure 13: How to recognise whether the correlation
between variables is significant:
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Table 3: Rs result for correlation between soil depth and percentage of vegetation coverage
Evidently the Rs value of 0.336 is below both critical values, hence there is no significant correlation
between soil depth and vegetation percentage as it is smaller than both critical values.
Figure 14: *bar graph clean visual representation of the quantitative data
The graphs show the positive correlations after having removed anomalies from the 100m interval
from table 2.
Although the Rs showed no relationship, after analysing table 2, it can be identified that there is a
positive correlation between soil depth and percentage vegetation as at 2.32cm soil depth there is
9.4% vegetation coverage and at 4.60cm depth, there is 32.6% vegetation.
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Normals
This occurs as the deeper the soil the more time the soil has to recover from soil contraction to form
suitable oxygenated soil for vegetation succession and provides more water and nutrients to plants
than shallow soils. This is demonstrated clearly after the average was taken (100m) 0.0% to (900m)
69.4%.
Additionally, hardpans (compacted layers of soil particles) reduce usable soil depth and increase the
chance of overland runoff, this is why breaking up hardpans by soil ripping is a standard technique in
most households, however, as the Morteratsch glacier is untouched it is unlikely to achieve such
vegetation %.
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As demonstrated some anomalies from analysing the two variables together that resulted in an
insignificant Rs correlation.
Anomalie Diagram
Figure 15:
Distance: 540
Soil depth: 0cm
Percentage of vegetation: 0%
Possible reasons for 0% of vegetation is due to
excess water causing overland-runoff (occurs
when precipitation exceeds the infiltration rate)
that infiltrates slowly into the soil resulting in
the plant’s ‘wilting point’. This limits soil from
having oxygen suitable for healthy roots and
this compacted soil leads to erosion.
0cm soil depth is simply due to either the large
rocks or sorted small pebbles between the
larger rocks that block the probe from reaching
soil.
Figure 16:
Distance: 740 Figure 17:
Soil depth: 0cm
Percentage of vegetation: 2%
As the Quadrat was placed onto two rocks, the
soil probe was not able to be inserted into the
soil, or the quadrats that were chosen had rocks
blocking the soil. Anomalies like such cannot be
prevented during data collection as the quadrat
must be placed where the 20 m lands from the
previous group, and 10 m from the river.
Such till occurs when glaciers pluck and deposit
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down-ice to form terminal, lateral medial and Figure 18:
ground moraines.
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Hypothesis 2
As ground wind speed increases the percentage of vegetation coverage decreases. Wind can remove
soil particles, causing the soil to erode and hinder growth of vegetation. In addition, freeze damage
caused by cold wind strips moisture from plants resulting in dehydration and damage to cell walls.
Figure 19: *Bar graph compares the raw quantitative data Figure 20: *Bar graph clearly shows negative correlation
between the two variables
Considering the raw data had multiple data points from the
same ground wind speed, averaging the data point from 0.5
intervals was the more effective way to display the
information.
Normals
This graph shows the higher the wind speed, the less vegetation %, such as at 2.1m/s there is 0%
vegetation, and at 0.0m/s there is 100% vegetation.
This is evident due to wind erosion. Erosion depletes organic matter, thus a decrease in soil
productivity for natural vegetation. When topsoil that contains organic matter such as nitrogen,
phosphorus and potassium (NPK), are eroded from the soil structure, this reduces the possibility of
efficient vegetation growth. Moreover, when there is a loss of mineralization, this results in the
degradation of soil (physical and chemical cycling in soil quality), making soil compact and hard for
aeration (oxygenated soil).
Anomalies
After analysing the graph, anomalies such as at 360m there is 27% vegetation coverage with 1.3m/s,
considering this as a high wind speed in relation to the other trials. This is due to the glacial till
surrounding the anemometer, thus blocking the wind from certain areas of the quadrat. The
vegetated quadrants were covered by the boulder.
Another reason as to why this occurs is wind picks up seeds and disperse them randomly, therefore
areas of higher wind s/m have more vegetation %, such as at 1.8m/s there is 13% of vegetation
coverage.
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Figure 21: *Visual representation of data collection
Hypothesis 3
There is a positive correlation between soil depth and distance from the glacier snout.
Considering that the Morteratsch glacier is retreating due to ablation, new land then has longer to
develop sufficient substrate depth for vegetation than the glaciated land before it.
Figure 22: *Visual graph clearly shows data plotted with Av. of 4, 20m distance marks, giving 100m
intervals and a total of 1000m
This map shows the positive correlation between distance from glacial snout and soil depth.
By excluding anomalies at 700m which was due to the fact that students got to choose which
quadrants they wanted to measure the soil depth, therefore students must have chosen 4 with the
highest soil depth which resulted in deeper soil. Soil depth increases further away from the snout of
the glacier by an average rate of 87%.
Figure 23: Calculation % error
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Figure 24: Process of glacier ablation
Normals
Soil depth can be affected by a range of variables;
● Poorly sorted till grain, boulders, pebbles, clay
Debris in the glacier is deposited by ice (till) as shown in the diagram above near the ablation zone.
As the ice in the U shaped valley moves from the area of accumulation to ablation, it acts as a
conveyer belt and transports debris located beneath, within, and above the glacier towards its
terminus, due to climate change the temperature of our atmosphere is increasing, hence the ice
retrieves/melts away, as shown in figure 22 The timeline shows an estimate of where the ice once
was and how deep the soil was at this point.
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Figure 25:*Visualisation of figure 24 scenario
Normals
The pressure of the snow that has accumulated over the ice gathers weight and builds up pressure
on the bottom layers, which then results in those layers of ice getting warmer and melting. Due to
friction, the ground underneath allows the glacier to move, during this process, the soil becomes
extremely compact and is additionally stripped from its topsoil layer that contains NPK (as explained
in hypothesis 2). Moreover, the soil takes an average of 3-5 years to fully replenish these nutrients
and therefore explains why the soil that is further away from the glacier snout has greater soil.
Criteria E
The aim of the investigation was to analyse the impact of the retreat of the Morteratsch
glacier.
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Hypothesis 1, there was a significant correlation between soil depth and vegetation
percentage after the data was organised within the spearman’s rank column in table 2. The
vegetation increases from 0.0% (1.76cm soil depth) to 69.4% (11.68cm soil depth). The
Spearman’s rank did not support this claim as the stat value of 0.036Rs, this was due to
environmental obstacles that were inevitable data collection errors, resulting in 4 anomalies
(ex. figure 15-18) extracted from the final graph (figure 14).
Hypothesis 2, it’s true when ground wind speed increased, the percentage of vegetation coverage
decreased. Figure 19 demonstrates raw data collection with 50 points, this was enough to
recognise a pattern, as at 2.1m/s - 0% vegetation, and at 0.0m/s - 100% vegetation. The
fluctuations are due to anomalies caused by environmental obstacles ex. in Figures 21-22.
Hypothesis 3, was correct, there is a positive correlation between soil depth and distance from
the glacier snout. Figure 22 was plotted with Av. of 4, 20m distance marks, giving 100m intervals and
a total of 1000m. It was easier to recognise the increase in soil depth as the distance physically
increased on the map, with an av. increase in depth of 87% each 100m. As of 100m, there was 0.0%
vegetation and this increased to 91.6 at 1000m away from glacier snout. The anomaly was at 700m
the soil depth was 76.0cm which was more than the next two distances 800m (60.6cm) and 900
(69.4cm), this was due to human error explained in figure 22.
All hypotheses on the impact of the retreat were supported.
Criteria F
After analysing the data, the investigation resulted in significant data that complimented all
hypotheses.
Strength:
The data was accurately gathered by using measuring tape 20m away from the previous group and
10m string from the river to place the quadrat in the correct position for data collection. Although
this led to anomalies such as in figure 17, this was simply due to natural debris (given that we chose
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a location that did not have any human interference) and not a data collection error. After extracting
this data we could see correlations such as figure 14.
As evaluated in the conclusion, the results supported our hypothesis due to a great deal of accuracy
that was presented in a range of quantitative and qualitative graphs, that finally supported what ‘the
impact of the retreat of the Morteratsch glacier was.
Weakness + Improvement:
Students choose where they stuck the soil probe, and use this specific quadrant for every data set
therefore a method to improve the accuracy of this is to use a consistent quadrant for each data
collection with the use of number recognition. This will guarantee consistency and more accuracy
throughout data collection.
Figure 26: number quadrant
Extension of the investigation:
1. Comparing data collected in summer vs winter
a. What was the impact of the retreat of the Morteratsch glacier in summer in
comparison to winter?
2. What are the effects of the Morteratsch (a glacier that is retreating) to the Jakobshavn
(glacier expanding in size). We can gather the wind speed, temperature and sea-level
elevation of both glaciers, then evaluate the difference that explains why the Morteratsch is
retreating.
a. What are the impacts of the retreat of the Morteratsch glacier to the expansion of
Jakobshavn?
With the use of extensions it is possible to delegate who can benefit from this set of data as the
extension could consist of different weather conditions and nature of the glacier itself.
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Works cited
ALPECOLE. (2011, August 29). Evapotranspiration and the Water Cycle. GEO.UZH. Retrieved
October 19, 2021, from
https://www.geo.uzh.ch/microsite/alpecole/static/course/lessons/09/09e.htm
Burga, C. A. (1999). Investigation area of Morteratsch glacier forefield [Illustration].
Institute Agroindustria. (2017, December 9). Soil science and plant nutrition. Scielo. Retrieved
October 14, 2021, from https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0718-
95162018000100001
Nagle, G., & Cooke, B. (2017). Geography: Course companion (2nd ed.). Oxford University Press.
National Park Service. (2020, January 21). Plant Succession. National Park Service. Retrieved
October 10, 2021, from https://www.nps.gov/kefj/learn/nature/plant-succession.htm
Ophardt, M. (2016, June 27). Garden Tips: Wind is tough on garden plants. Tri City Herald.
Retrieved October 6, 2021, from http://i-cityherald.com/living/home-garden/marianne-
ophardt/article85905332.html
Tilley, N. (2021, April 7). Tips For Saving Cold Damaged Plants. Garden Knowing How. Retrieved
November 2, 2021, from
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-
damaged-plants.htm
USGS. (2020). Evapotranspiration and the Water Cycle. USGS. Retrieved October 15, 2021, from
https://www.usgs.gov/special-topic/water-science-school/science/evapotranspiration-and-
water-cycle?qt-science_center_objects=0#qt-science_center_objects
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