Investigating the Effects of Deforestation on Water Quality in the Wüstebach Catchment, Germany

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RESEARCH PROPOSAL: INVESTIGATING THE EFFECTS

OF DEFORESTATION ON WATER QUALITY IN THE

WÜSTEBACH CATCHMENT, GERMANY

Kerri-Leigh Robinson

11442034

The Research Proposal 5264REPR6Y

EXAMINER: DR. ERIK CAMMERAAT ASSESSOR: PROF. DR. ROLAND BOL DAILY SUPERVISOR: DR. HEYE BOGENA DATE OF SUBMISSION: 16 JANUARY 2020

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Summary

Deforestation events have the ability to alter the cycling of elements in forest ecosystems and nearby freshwater systems. Analyzing the effects of deforestation on water quality is important in informing management and conservation efforts of catchment areas. This proposal proposes to analyze the effects of deforestation on water quality by assessing the stream composition and runoff data of a catchment stream that has been disturbed by deforestation. The composition analysis will be done with respect to the carbon and nitrogen cycle as these cycles are interlinked and affect the performance of ecosystems. The soluble form of nitrogen, nitrate, and the most abundant form of carbon in aquatic systems, dissolved organic carbon, will be analyzed in a headwater catchment stream that has been affected by deforestation in Wüstebach, Germany. This catchment site serves as an ideal analysis scenario as it forms part of the TERENO initiative and thus the site has been monitored for more than a decade. Therefore, stream composition data exists for the entire period prior to deforestation, during deforestation and post deforestation.

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https://courses.lumenlearning.com/microbiology/chapter/biogeochemical-cycles/ _______________________ 7 Figure 2: The N Cycle (Driscoll, et al., 2013) __________________________________________________ 10 Figure 3: Map indicating the four TERENO observatories, their experimental catchments and research stations in Germany (Zacharias, et al., 2011) _________________________________________________________ 13 Figure 4: Map of the Eifel/Lower Rhine Valley Terrestrial Observatory (Umweltbundesamt GmbH, 2020a) _ 15 Figure 5: Map of the Wüstebach catchment indicating sampling locations, soil types and the sub catchments of the tributaries (Weigand, et al., 2017) ________________________________________________________ 16 Figure 6: Map of the Wüstebach experimental catchment and the reference catchment indicating the major soil types and the instrumentation in the area. The aerial images on the right indicate the extent of deforestation that has occurred between 2013 and 2016 (Bogena, et al., 2018). ______________________________________ 17

List of Tables

Table 1: Outline of the workflow of the methodology (Author, 2019) ________________________________ 20 Table 2: Time schedule for the research project (Author, 2019) ____________________________________ 23 Table 3: Budget for the 5-month research project (Author, 2019) ___________________________________ 24

List of Abbreviations

C Carbon

DOC Dissolved Organic Carbon

DOM Dissolved Organic Matter

IPCC Intergovernmental Panel on Climate Change

N Nitrogen

OECD Organization for Economic Co-operation and Development

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1 Introduction

Forests systems serve as important resources that provide many socio-economic functions and services to humans and ecosystems (Dessie & Bredemeier, 2013). Despite the importance of forests to humans, the rate of deforestation is increasing globally, and this type of disturbance can have ripple effects on connected systems. According to Dessie & Bredemeier (2013), deforestation has the ability to alter the natural biogeochemical cycling of elements, and this can be seen by analyzing stream water runoff from catchments where forests have been cleared/harvested (Mupepele & Dormann, 2017). Since anthropogenic activities can alter water quality, it is important that these freshwater systems are appropriately managed and conserved (Bogena, et al., 2018).

Biogeochemical cycling can be defined as the pathway by which a chemical element cycles through the biosphere, atmosphere, hydrosphere and the lithosphere (IPCC, 2014) (National Science Foundation, 2009). Several biogeochemical cycles are operating at different levels at any moment in time in order to enable balance in the environment. Two of the most common biogeochemical cycles are the carbon (C) and nitrogen (N) cycles as they are tightly linked with one another due to the metabolic requirements of organisms for these two elements (Bala, et al., 2013) (Kaplan & Newbold, 2000). Changes in N or C availability will not only influence the biological activity in an environment, but it will also influence the availability and requirements for the other element (Bala, et al., 2013). In the long term, the availability of these elements, or lack thereof, will affect the structure and performance of ecosystems.

When assessing the impact of deforestation on water quality in terms of the C and N cycles, it is useful to assess the forms of C & N that are soluble upon contact with water and are necessary for marine ecosystem functioning. Nitrates (𝑁𝑂#$) and Dissolved Organic Carbon (DOC) are highly soluble forms of N and C and thus they move readily from the terrestrial environment to the marine system when saturated (WHO, 2011). Other forms of C are also soluble, however DOC comprises the largest pool of organic C in marine environments and it serves as a vector for the transport of nutrients to microorganisms within water bodies (Mostovaya, et al., 2017). According to published literature on the influence of deforestation on runoff generation, deforestation events have the potential to increase the runoff and sediment yields from the catchment area (Gholami, 2013) (Hlásny, et al., 2015), and therefore it can be inferred that nutrient levels in catchment streams will be altered by the increased runoff and sediment yields.

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When assessing literature on studies focused on the effects of deforestation on nitrate content in temperate streams it is indicated that nitrate content increases (Malek & Krakowian, 2012) and this increase can continue for up to five years after deforestation (Mupepele & Dormann, 2017). Through examining studies that assessed the effects of deforestation on both DOC and N content it is suggested that both DOC & N content increase in streams affected by deforestation (Gandois, et al., 2012) (Jacobs, et al., 2017), however Gandois et al. (2012) suggested that the rise in DOC may have more to do with catchment characteristics than land-use changes. However, both of these studies were conducted in tropical regions and the results for temperate regions may be different. Therefore, investigating the effects of deforestation on the C & N cycle in temperate regions is useful in filling a knowledge gap and informing conservation and management efforts for these regions.

An ideal research site to study the effects of deforestation on water quality would be one in which water quality and composition has been monitored for a long period of time. Ideally this water quality and composition monitoring would be assessed at regular intervals starting before deforestation began and spanning to a few years after the deforestation event. Analyzing this data would give a holistic representation of stream changes due to deforestation. The Terrestrial Environmental Observatories (TERENO) initiative has various research sites situated around Germany which have been equipped to measure changes in the environment (Zacharias, et al., 2011). One of the TERENO observation sites known as Wüstebach research site has been purpose built in order to investigate the effects of deforestation on the ecosystem, hydrology and biogeochemical processes (Umweltbundesamt GmbH, 2020b). This serves as an ideal research site as runoff data, water quality data and water composition data exist for the entire timeframe spanning from pre deforestation to post deforestation.

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2 Research Aim

The main objective of this study is to assess the impact of deforestation on the water quality of streams in the Wüstebach catchment. This will be done by investigating two elements of water quality, namely: DOC and nitrate content. Assessing how deforestation alters the concentration of certain elements could assist in making future projections about the influence of deforestation on water quality and inform land management practices.

2.1 Research Questions

1. How does a deforestation event alter the in-stream DOC content and nitrate content in the Wüstebach catchment?

2. Has deforestation influenced the runoff pattern in the Wüstebach catchment in comparison to the reference stream?

3. How long does it take for stream composition and discharge to stabilize to prior deforestation levels?

The following hypotheses have been set and will be tested in the research paper:

1. Nitrate and DOC content will initially increase in the streams in the Wüstebach catchment following deforestation however the nitrate content will decrease as more DOC enters the stream system.

2. Runoff and discharge of the catchment area will increase after the period of deforestation

3. The stream system will take an average of 20 years to return to nutrient composition levels prior to deforestation

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3 Theoretical Framework

3.1 The Carbon Cycle

C is an essential element to all life on earth (Reynolds, 2012). All living organisms are formed from organic molecules that contain C and the availability of this element is made possible by the C cycle. The global C cycle, seen in figure 1 below, can be viewed as a series of reservoirs of C in the earth system which are linked by exchange fluxes of C (Bala, et al., 2013). The earth’s C reservoirs include the oceans, terrestrial system and the atmosphere (Post, et al., 1990). The C cycle can be easily explained as two interlinked cycles namely the biological C cycle and the biogeochemical C cycle (Fisher, 2019). The biological C cycle explains the transfer of C between living organisms and the biogeochemical cycle explains the long-term cycling of C through land, water and air (Fisher, 2019).

Figure 1: The C Cycle (modification of work by NOAA). Source:

https://courses.lumenlearning.com/microbiology/chapter/biogeochemical-cycles/

The biological C cycle concerns the transfer of C amongst living organisms. Terrestrial autotrophs photosynthesize by coupling solar energy, water and 𝐶𝑂_& from the atmosphere and use it to produce high energy compounds, e.g. glucose, which is later used by the autotroph in the process of respiration (Fisher, 2019). Marine autotrophs receive their 𝐶𝑂_& in the dissolved form (𝐻_&𝐶𝑂_#). In contrast to autotrophs, heterotrophs receive C by consuming autotrophs, and they break down the high energy compounds in the process of respiration (Fisher, 2019). Respiration involves the removal of C from the high energy compound and the release of 𝐶𝑂_&

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back into the atmosphere creating a cycle (Fisher, 2019).The biogeochemical C cycle concerns the long-term cycling of C through geologic processes (Fisher, 2019). C can be stored for extended periods of time in what is termed C reservoirs. There are three active environmental reservoirs, and these include the atmosphere, the oceans and the terrestrial system (Post, et al., 1990).

The atmosphere is an environmental reservoir as it stores C in the form of 𝐶𝑂_&, which is used in the process of photosynthesis, as discussed above. The terrestrial reservoir includes C stored in the earth’s core, in the earth’s soils and in all terrestrial organisms. C stored in the soil is stored as organic C and it forms as a result of the decomposition of autotrophs and heterotrophs or from the weathering of minerals and rocks (Fisher, 2019). Organic C stored under the surface of the earth are termed fossil fuels and they are formed from decayed plants and animals from millions of years ago (Fisher, 2019). Out of all the C reservoirs, the oceanic reservoir has the largest concentration of C and in contrast, the atmosphere contains the smallest concentration (Post, et al., 1990). As figure 1 depicts, the oceanic reservoir is closely linked to the terrestrial reservoir and the atmospheric reservoir as it exchanges C with both. According to Post, et al. (1990), the oceanic reservoir stores C in three different forms that include DOC, dissolved inorganic C and particulate organic C. Dissolved inorganic C consists of dissolved 𝐶𝑂& and bicarbonate (𝐻𝐶𝑂_#−) and carbonate ions (𝐶𝑂_#&_) (Post, et al. , 1990). DOC consists of both large and small organic molecules and particulate organic C is comprised of organic molecules that are larger than 0.7 micrometers such as live organisms and fragments of decaying plant/animal material (Post, et al., 1990) (Zhuiykov, 2014). Quantitatively, DOC is the largest pool of organic C in marine environments and it is a vector of energy and nutrients from terrestrial to aquatic systems for heterotrophic organisms (Mostovaya, et al., 2017).

3.1.1 DOC and Water Quality

DOC can hence be defined as the organic matter dissolved in water that is capable of passing through a filter which removes material between 0.22 and 0.7 micrometers (Zhuiykov, 2014). Organic C is formed as a result of decomposition of plant or animal material and this C may partially dissolve upon contact with water. This organic C can originate from within the body of water and from the external environment. DOC that originates within the internal environment is termed autochthonous DOC and it is formed from the decayed remains of aquatic organisms and precipitates (Matthews, 2013). Allochthonous DOC is DOC originating

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from the catchment and the surrounding environment (Matthews, 2013). When water originates from areas with a high proportion of organic soils, this organic matter can drain into rivers and lakes and end up in aquatic systems.

According to Kaplan & Newbold (2000), DOC concentrations in streams and rivers, under baseflow conditions, can range from < 0.5 𝑚𝑔𝐶𝐿>?_{in alpine and everygreen forests to}_> 30 𝑚𝑔𝐶𝐿>?_{where streams and rivers drain wetland areas. Factors that influence the} concentration of DOC in water sources include catchment vegetation; climate; microbial activity; soils and hydrology (Kaplan & Newbold, 2000). Since DOC is an important food source for marine microorganisms and is necessary to ensure ecosystem health, it is important for DOC concentrations in a water body to be above a certain level depending on ecosystem requirements. When assessing DOC content with respect to drinking water quality, water with high levels of DOC is a cause for concern (Ledesma, et al., 2012). This is because DOC can act as a vector for other contaminants from the terrestrial environment and this, in turn, increases the cost of the drinking water treatment process (Ledesma, et al., 2012).

3.2 The Nitrogen Cycle

N is the fourth most plentiful element in cellular biomass, and it forms the majority of the earth’s atmosphere (Ngatia, et al., 2018) (Stein & Klotz, 2016). N is an essential element of amino acids which are the building blocks of proteins and thus it is a vital element for all living things on earth (Stein & Klotz, 2016). Like C, N can exist in different forms and it changes as it goes through the processes of the N cycle (see figure 2 below). Despite the vast abundance of N in the atmosphere, N absorption into organisms is challenging. For autotrophs to receive N they require symbiotic bacteria (Stein & Klotz, 2016) to perform biochemical processes termed fixation, nitrification, ammonification/mineralization, and denitrification (Fisher, 2019).

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N fixation is the first step of the N cycle and it includes the conversion of atmospheric N (𝑁_&) into a usable form of ammonium (𝑁𝐻B+) (Zhu, et al., 2015). This process requires N gas to be deposited into soils and surface waters mainly via precipitation. As evident in figure 2 above, the N gas bonds can be broken through three types of fixation, namely atmospheric fixation (lightning), chemical N fixation (man-made), and biological N fixation (bacteria) (University of Hawaii, 2007). Biological N fixation is the most common form of fixation and this occurs when 𝑁_& is deposited into the soils undergoes changes due to the bacteria present in the soil. These bacterium separate the two N atoms and enable them to combine with hydrogen to form ammonia (𝑁𝐻_#) and then ammonium (𝑁𝐻_B+).

𝑁𝐻_B+ is then converted to nitrite (𝑁𝑂_&$) and nitrate (𝑁𝑂_#$) by further microbial processes in the soil. This process is very important as plants are incapable of absorbing ammonia. The process of converting ammonia to nitrates is termed nitrification. Nitrates are then taken up by primary producers during their growth and it is used in the production of organic nitrogenous compounds (WHO, 2011) in the process of assimilation. Decaying plants and animals feed back into the N cycle as the organic N is released back into the soil. The conversion of organic N to ammonium is termed ammonification/ mineralization (University of Hawaii, 2007). Conditions that affect N mineralization include the quantity of organic N; temperature; oxygen; moisture content; and the ratio of carbon to nitrogen (C:N) of the decomposing organic matter

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(University of Hawaii, 2007). According to the University of Hawaii (2007), microorganisms in the soil need both C and N to mineralize and net mineralization occurs when the ration is less than 20:1.

Immobilization is the reverse reaction of mineralization and it occurs when decaying organic matter is low in N i.e. has a high C:N ratio (University of Hawaii, 2007). Denitrification is the final stage of the N cycle and it involves the conversion of 𝑁𝑂_#$ into gaseous N (𝑁_&) (Stein & Klotz, 2016) through microbial processes and it occurs through the removal of oxygen (Ngatia, et al., 2018). According to OECD (2018), total denitrification is influenced by the available oxygen, organic C and pH of the soil. This process thus returns N from the biosphere to the atmosphere (OECD, 2018) and closes the cycle.

3.2.1 Nitrates and Water Quality

As discussed above, nitrates (𝑁𝑂_#$) are necessary as they are readily taken up by primary producers (WHO, 2011). The 𝑁𝑂_#$ ion is the stable form of combined N for oxygenated systems and it is very soluble in water (WHO, 2011). Anthropogenic disturbances have the potential to alter the N cycle and affect the quantity of ions found in different parts of the cycles. Anthropogenic activity’s that are known to alter the N cycle include: the combustion of fossil fuels and biomass (Zhu, et al., 2015) (Fisher, 2019); N-fixing plants cultivation (Zhu, et al., 2015); the application of artificial N fertilizers to increase crop production (Fisher, 2019); and also through clearing vegetation which results in increased mineralization and therefore a buildup of nitrates in the soil (Rusinga, et al., 2008). This is owed to the fact that decaying vegetation that is rich in N will release N back into the soil, and due to the lack of bacteria present in the soil, this N will be in excess of soil biota requirements leading to N loss through leaching or nitrous oxide emissions (Zhu, et al., 2015) (Rusinga, et al., 2008). In this way, 𝑁𝑂_#$can potentially leach into groundwater or be carried away by surface runoff to nearby water bodies (Zhu, et al., 2015). It is therefore clear that vegetation clearing/deforestation can alter the N cycle by producing large amounts of mobile nitrates.

Water pollution caused by N can impact both the ecosystem, animal and human health (OECD, 2018). Excessive levels of N in water bodies cause a eutrophication which in turn can lead to anoxic events (Ngatia, et al., 2018). Eutrophication occurs when a body of water contains a high level of nutrients, often due to run-off from the land, and these nutrients promote excessive

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growth of plant life and algae blooms (Ngatia, et al., 2018) (OECD, 2018).Excessive growth of plants and algae can block the passage of light into deeper waters (OECD, 2018) .When these plants die and decompose, oxygen is removed from the water resulting in a lack of available oxygen. This is commonly known as an anoxic event and it is often deadly for other marine life as it deprives them of oxygen. High concentrations of nitrates in drinking water can also cause Methemoglobinemia in infants (OECD, 2018) and according to Schullehner, et al. (2018), high nitrate content in drinking water may increase the risk of colorectal cancer in humans.

3.3 Relationship between DOC & Nitrates

As mentioned above, the total denitrification in the N cycle is influenced by the available oxygen, organic C and PH of the soil (OECD, 2018). Therefore, DOC and its concentration in water sources can impact N dynamics when under anoxic conditions (Sobczak, et al., 2003) (Bernhardt & Likens, 2002). This is because DOC increases the process of denitrification and thus increases the conversion of nitrate (𝑁𝑂_#$) to N gas (𝑁_&). In this way, the quality and quantity of C influences the rate of denitrification and links the C & N cycles (Bernhardt & Likens, 2002). This would infer that as DOC increases, nitrate content decreases creating a negative relationship between the two variables.

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4 Terrestrial Environmental Observatories (TERENO)

In order to document the long-term impacts of climate and global change at a regional level, in 2008 the German Helmholtz Association began establishing a network of Terrestrial Environmental Observatories (Zacharias, et al., 2011). A total of four observatories were established, namely: the Bavarian Alps/ pre- Alps Observatory; Eifel/ Lower Rhine Valley Observatory; Harz/ Central German Lowland Observatory; and Northeastern German Lowland Observatory. These observatories extend across the country from the lowlands in northern Germany to the Bavarian Alps and the geographic locations can be observed in figure 3 below. The selection of these locations were based due to their placement in regions with a high vulnerability to climate and global change and they are also representative for Germany and other Central European Countries (Zacharias, et al., 2011).

Figure 3: Map indicating the four TERENO observatories, their experimental catchments and research stations in Germany (Zacharias, et al., 2011)

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According to Bogena et al. (2018), the goal of the TERENO observatories is to investigate the consequences of global change on the terrestrial system in two ways. Firstly by providing a data series in excess of 15 years of system states and changes for the analysis and prediction of climate and land use change consequences; and secondly by creating and applying integrated model systems that can inform effective prevention, mitigation and adaptation strategies. The observatories supply continuous data about hydrology, climatology, pedology, biology and socio-economics to allocated research centers (Bens, et al., 2012). These research centers are responsible for the processing of data and the instrumentation of the observatories.There are six Helmholtz Association Centers responsible for these observatories and they are: Helmholz-Zentrum für Umweltforschung (UFZ), Karlsruhe Institut für Technologie (KIT), Deutsches Zentrum für Luft und Raumfahrt (DLR), Helmholtz-Zentrum Potsdam- Deutsches GeoForschungZentrum (GFZ); Forschungszentrum Jülich (FZL), Helmholtz Zentrum München- Deutches Forschungszentrum für Gensundheit und Umwelt (HMGU).

The TERENO initiative is in a sense complimentary to existing measurement networks in Germany and the rest of the world (Zacharias, et al., 2011). According to Zacharias, et al. (2011), these existing networks include the Critical Zone Observatory Program, FLUXNET, Long Term Ecological Research (LTER) Network, and the Integrated Carbon Observation System (ICOS).

4.1 The Eifel/Lower Rhine Valley Observatory

Forschungszentrum Jülich is responsible for the Eifel/Lower Rhine Valley observatory. The central monitoring site of this observatory is the River Rur catchment which spans over an area of 2354 𝑘𝑚&_{. According to Bogena, et al. (2018), altitude increases from the 64 m to 630 m} from the northern to the southern part of the observatory. The northern part of the observatory is characterized by higher mean annual temperatures (10°𝐶) than the south (7°𝐶) and a lower annual precipitation of 650 mm in comparison to 1300 mm in the south. This observatory displays a prominent land use gradient where the northern region is characterized by urbanization and agriculture whilst the southern low mountain range is sparsely populated and contains drinking water reservoirs (Umweltbundesamt GmbH, 2020a). Along the gradients of this observatory, instrumented test sites have been built in order to investigate specific aspects of the terrestrial system. A map of the Eifel/Lower Rhine Valley Observatory can be seen in figure 4 below.

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Figure 4 indicates that the observatory is composed of three research sites, namely: research site Selhausen; research site Rollesbroich; and research site Wüstebach, and a meteorological observatory. The research site Wüstebach is an example of an intensive test-site that was created in order to assess hydrometeorological characteristics of the catchment (Zacharias, et al., 2011). The southern part of the Eifel/Lower Rhine Valley Observatory forms part of the Eifel National park and according to Zacharias et al. (2011), climate change predictions for this region indicate an increase in temperature and an increased risk of flooding. This is due to the increased rate of winter precipitation in the west of Germany.

Figure 4: Map of the Eifel/Lower Rhine Valley Terrestrial Observatory (Umweltbundesamt GmbH, 2020a)

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5 Site Description (Research site Wüstebach)

In 2004, the TERENO Wüstebach site was established and between 2007 and 2010 the site was equipped with various measurement instruments that enable the long-term monitoring of the environment (Bogena, et al., 2015). The purpose of this site is to investigate the consequences of deforestation on hydrological processes, the ecosystem and biogeochemical cycles using an integrated observation approach (Umweltbundesamt GmbH, 2020b).

5.1 Location and Characteristics

The TERENO Wüstebach catchment is in the southern part of the Eifel/Lower Rhine Valley Observatory. It falls within the Eifel National Park and it is in close proximity to the German- Belgian border located at 50°30G_{16 N and 6°20" 𝐸 (𝑊𝐺𝑆 84). The site covers an area of 38.5} ha and sits at an average attitude of 610 meters above sea level. The catchment is characterized by small headwater streams that receive an annual precipitation of approximately 1220 mm per annum which can be seen in figure 5 below. The Wüstebach catchment and the Püngelbach catchment combine to form the headwater of the Erkensruhr river. North east of the catchment is reference stream which is also instrumented to serve as a comparison for the Wüstebach stream. The reference stream has a size of 11 ha and feeds into the Wüstebach stream approximately 10 m downstream. This alliance can be seen in figure 5 below.

Figure 5: Map of the Wüstebach catchment indicating sampling locations, soil types and the sub catchments of the tributaries (Weigand, et al., 2017)

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5.2 Vegetation and Deforestation

Norway Spruce (Piceas abies) is the dominant vegetation found in the catchment as this species was planted in 1946 for timber production. However, efforts are currently being made to restore the Eifel National Park to near natural deciduous forest (Umweltbundesamt GmbH, 2020b). These efforts have included the clear cutting of an area of 9ha within the Wüstebach research site. This deforestation was undertaken by the National Park Forest Management and it occurred in the late summer/early autumn of 2013. The extent of the deforestation event can be seen in figure 6 below. Significant effects are expected in water quality as a result of the deforestation event. The reference site which is located North east to the catchment is an unaffected reference site that has not been subjected to deforestation (see figure 6). Using the reference stream, comparisons can be made between water quality in the deforested stream and the reference stream.

Figure 6: Map of the Wüstebach experimental catchment and the reference catchment indicating the major soil types and the instrumentation in the area. The aerial images on the right indicate the extent of deforestation that has occurred between 2013 and 2016 (Bogena, et al., 2018).

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5.3 Pedology and Geology

The bedrock of this catchment is comprised of weathered Devonian foliated siltstone and claystone and it contains isolated quartzite (Schuster, 2010). This layer is covered by a periglacial solifluction layer which ranges from approximately 1 to 2 meters in thickness. The pedology in this region can be seen in figure 5 and figure 6 above. These figures indicate that the hillslopes are dominated by Cambisols and Planosols whilst the valley is dominated by gleysols and histosols. The dominant soil texture in this catchment is silty clay loam and the overlying litter layer ranges from 0.5 to 14 cm across the catchment (Umweltbundesamt GmbH, 2020b).

5.4 Observation Instrumentation

As mentioned above, the Wüstebach research site was equipped with monitoring instrumentation between 2007 and 2010. This means that environmental measurements were taken long before the deforestation occurred. In order to create an integrated observation system the site was equipped to measure the following parameters: runoff, groundwater and water quality; meteorology; soil moisture; water balance; sapflow; isotope monitoring; soil respiration; and soil properties (Bogena, et al., 2015). The instrumentation used to measure these parameters will now be discussed. For more detailed information on the instrumentation in the Wüstebach catchment- please see the appendix.

Three runoff gauging stations have been installed in the research site to measure stream discharge and these can be seen in figure 6 above. A total of 8 piezometers have been installed in the site in order to assess groundwater levels across the catchment. In an effort to assess water quality, weekly grab samples are taken for chemical analyses at several locations along the Wüstebach stream (Bogena, et al., 2015). In addition to these locations, weekly grab samples are also taken from the main tributaries of the stream and the reference stream (see figure 6 above). To measure changes in meteorology, the main meteorological measurements are condensed around a 38 m high eddy tower that has been installed in the north western area of the catchment. Measurements taken from the tower, above the canopy, at a frequency of 20 Hz include: temperature; humidity; 3D wind vector; and 𝐶𝑂& concentration. Eddy covariance (EC) and radiation is also measured from the tower and a second EC station has been installed in the deforested area (Bogena, et al., 2015).

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Soil moisture monitoring is done through the wireless soil moisture sensor network SoilNet (Bogena, et al., 2015). 150 sensor units have been placed in the catchment that wirelessly provide soil information via several router devices to a central network coordinator unit (Bogena, et al., 2015). Water balance is assessed through six lysimeters installed in the catchment (Bogena, et al., 2015). These instruments also gather data on precipitation, evapotranspiration, and changes in soil water storage. To measure the sapflow fluxes of the research catchment, two sites are monitored, and equipped with sapflow sensors to determine transpiration fluctuations. Isotope monitoring is done by collecting weekly precipitation samples for isotopic analysis (Bogena, et al., 2015). To measure soil respiration, there are two transects installed in the field that measure a total of 84 points that are instrumented with PVC collars. Weekly measurements of soil respiration, soil temperatures and soil moisture measurements are done (Bogena, et al., 2015). To monitor soil properties in the catchment, a series of soil sampling campaigns have been done starting one month prior to the deforestation at a total of 143 sampling sites.

6 Methodology

The research process will be divided into four phases, namely: 1. Prefaces; 2. Data Collection; 3. Data Interpretation and analysis; and 4. Synthesis and conclusion. An outline of the workflow can be seen in table 1 below. Phase 1 will include identifying the problem associated with deforestation and water quality and outlining the objectives of the research paper in an effort to address the main aim. Phase 1 will also comprise the majority of the literature review however existing literature will be consulted, compared and reviewed throughout the research process. Phase 2 will include comprise of collecting long-term water quality data about the research area. This data will include measurements from both the Wüstebach catchment stream and the reference stream, in order to be able to make comparisons regarding the effects of deforestation. Data interpretation and analysis of results will be conducted during phase 3 of the research process. This will be accomplished by performing statistical analysis on the lab results collected in phase 2. MATLAB (R2019b Student), Microsoft Office and IBM SPSS Statistics is the software that will be used to analyze the data, investigate trends, and to compare results with existing published data. Phase 4 of the research process will include synthesizing the findings of the analysis with existing literature and drawing comparisons. The proposed methodology for assessing the research questions will now be discussed.

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Table 1: Outline of the workflow of the methodology (Author, 2019) LI TE RA TU RE R EV IE W PHASE 1 PREFACES PHASE 2 DATA COLLECTION PHASE 3 DATA INTERPRETATION & ANALYSIS PHASE 4 SYNTHESIS & CONCLUSION Problem formulation Aims and Objectives

Quantitative Water Quality Data

• Dissolved Organic Carbon • Nitrate

• Reference Stream • Wüstebach Stream

Synthesize findings with literature Limitations & Recommendations

Conclusion Final Report Data Analysis • MATLAB • MS Office • IBM SPS Statistics Interpretation of Results

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6.1 Research Question 1

How does a deforestation event alter the in-stream dissolved organic carbon content and nitrate content in the Wüstebach catchment?

In an effort to assess changes in DOC and nitrate, data on the chemical composition of the water will be gathered from the Jülich Forschungszentrum for the time spanning from June 2013 to June 2017. This data will be prepared, and a descriptive time series analysis will be performed for this period. This will provide a visualization of the catchment two months prior, including and after the deforestation event took place. This descriptive time series will then be combined with the time series published by Weigand, et al. (2017), in order to create an eight year descriptive time series of DOC and nitrate content in the Wüstebach catchement. This will then deliver an overview of DOC and nitrate concentration in the Wüstebach streams over an eight year period. Statistical software will be used to create box and whisker plots of the sampling stations for the four year period, which will be compared to the published data. Regression and correlation analysis will also be carried out, in order to assess the distribution of the variables in relation to eachother. Using the results generated from pre deforestation and post deforestation for both the Wüstebach and the reference stream, comparisons can be made about the influence of deforestation on C & N content in the catchment.

Has deforestation influenced the runoff pattern in the Wüstebach catchment in comparison to the reference stream?

As mentioned in the instrumentation section of the site description, the Wüstebach site is equipped with three runoff gauging stations which measure stream discharge. Two of them are installed in the Wüstebach stream and one is in the reference stream. An analysis of discharge data for a four-year period will be done starting two years prior to the deforestation and continuing until two years after the deforestation event. This will be realized by creating a descriptive time series of discharge data from each station. Through doing this- comparisons can be drawn between the reference and Wüstebach stream and the effect of deforestation on the runoff pattern can be assessed. Published literature on discharge data from the Wüstebach catchment will also be used in order to compare current discharge rates to prior deforestation runoff rates.

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How long does it take for stream composition and discharge to stabilize to prior deforestation levels?

To answer this research question, the chemical characteristics of the water in the Wüstebach catchment will be analyzed from 2011 to 2015 to cover a four-year period. This time frame may be extended if stabilization is undetectable after two years of deforestation. Each major element present in the catchment will be plotted in a time series graph in order to detect changes in stream composition as a result of deforestation. This data has been collected during weekly grab samples and processed by the Jülich Forschungszentrum. For nitrate and DOC, the published time series and data from Weigand, et al. (2017) will be used and combined with the time series created to answer research question 1. Using the statistical software, the data will be analyzed to investigate any trends. These trends will be analyzed and combined with an evaluation of existing literature on stream stabilization after deforestation, and an estimation on the recovery time can be formulated. To calculate the length of time it will take for discharge rates to stabilize, the data gathered to answer research question two will be utilized and potentially a larger time frame will be analyzed if discharge rates do not begin to stabilize in the two years post deforestation. The statistical analysis performed on this data will be combined with a literature review on discharge stabilization post deforestation in an effort to make an estimation on discharge recovery time.

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7 Time Schedule

The time schedule can be seen in table 2 below, the proposed research project begins in December 2019 and completes in October 2020.

Table 2: Time schedule for the research project (Author, 2019)

December January February August September October

Research Proposal x x Data Collection x x Statistical Analysis x x Data Analysis x x Report Writing x x Hand in x Final Presentation x

* Break between February and August is due to the Tesla minor that I will be completing during this period.

8 Funding

The first two months of the research will be conducted in Jülich Germany and the remainder of the research process will be conducted in Amsterdam. Thus, additional costs will only be incurred for the first two months. These costs can be seen tabulated below (Table 3). The accommodation in Jülich will cost € 684 for ~6 weeks and the transportation getting to Jülich from Amsterdam via train will cost € 50 per journey. The consumables include food, electricity and washing costs and these will be approximately € 200 per month. Finally, the transportation to and from Jülich Forschungszentrum via train will cost approximately € 4 per working day

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adding up to € 124 for the 31 working days. The total cost of the master’s thesis will therefore be €1 308.00.

These costs will be covered by the researcher through the assistance of the Jülich Forschungszentrum that has kindly offered to employ the researcher as a part-time assistant for the first two months of the research process. This payment will assist in covering some of the costs of the research and the additional costs will be borne by the researcher.

Table 3: Budget for the 5-month research project (Author, 2019)

Month 1 Month 2 Month 3 Month 4 Month 5 Total

Accommodation € 460, - € 224, - - - - € 684, - Consumables € 200, - € 200, - - - - € 400, - Transportation: Train (Amsterdam-Jülich) € 50, - € 50, - - - - € 100, - Transportation: € 64 € 60 - - - € 124, - Total € 1 308, -

9 Insurance and Safety

For the duration of the fieldwork and data processing that will be completed in Jülich, Germany, I will be using European Health Insurance (EHIC) that has been granted through the National Health Service (NHS) of the United Kingdom. For third-party insurance, I have taken student insurance from ING Bank in the Netherlands that is valid until the 20th_{of May 2020.} The necessary medical form has been submitted to the medical officer of the University of Amsterdam and the signed field declaration can be found in the appendix.

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10 Equipment List

® Laptop

® MATLAB- MathWorks (Software) ® IBM SPSS Statistics (Software) ® Microsoft Office (Software) ® Safety Shoes

® Outdoor Gear

® Pen & Writing Paper ® External Hard drive

11 Bibliography

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Bens, O. et al., 2012. TERENO – Eine Monitoring- und Forschungsplattform zur Erfassung langfristiger Auswirkungen des Globalen Wandels auf regionaler Ebene. System ERde. Bernhardt, E. S. & Likens, G. E., 2002. Dissolved organic carbon enrichment alters nitrogen

dynamics in a forested system. Ecology, 83(6), pp. 1689-1700.

Bogena, H. R. et al., 2015. A terrestrial observatory approach to the integrated investigation of the effects of deforestation on water, energy, and matter fluxes. Earth Sciences, 58(1), pp. 61-75.

Bogena, H. R. et al., 2018. The TERENO-Rur Hydrological Observatory: A Multiscale Multi-Compartment Research Platform for the Advancement of Hydrological Science. Vadose Zone Journal, 17(180055).

Dessie, A. & Bredemeier, M., 2013. The Effect of Deforestation on Water Quality: A Case Study in Cienda Micro Watershed, Leyte, Philippines. Resources and Environment, 3(1), pp. 1-9.

Driscoll, C. T. et al., 2013. Cross-site comparisons of precipitation and surface water chemistry. In: Long-Term Trends in Ecological Systems . s.l.:s.n., pp. 46-50. Fisher, M. R., 2019. Biogeochemical Cycles. s.l.:Creative Commons.

Gandois, L. et al., 2012. Impact of deforestation on solids and dissolved organic matter characteristics of tropical peat forests: implications for carbon release. Biogeochemistry, 114(1-3), pp. 183-199.

Gholami, V., 2013. The influence of deforestation on runoff generation and soil erosion (Case study: Kasilian Watershed). Journal of Forest Science , 59(7), pp. 272-278. Hlásny, T. et al., 2015. Effect of deforestation on watershed water balance: hydrological

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IPCC, 2014. Carbon and Other Biogeochemical Cycles. In: Climate Change 2013- The Physical Science Basis. s.l.:Cambridge University Press, pp. 465-570.

Jacobs, S. J. et al., 2017. Land use affects total dissolved nitrogen and nitrate concentrations in tropical montane streams in Kenya. Science of the Total Environment, Volume 603-604, pp. 519-532.

Kaplan, L. A. & Newbold, J. D., 2000. Surface and Subsurface Dissolved Organic Carbon. In: Streams and Ground Waters. Pennsylvania: Academic Press, pp. 237-258.

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Volume 432, pp. 1-11.

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Mostovaya, A., Hawkes, J. A., Dittmar, T. & Tranvik, L. J., 2017. Molecular Determinants of Dissolved Organic Matter Reactivity in Lake Water. Frontiers in Earth Science, 5(106). Mupepele, A.-C. & Dormann, C. F., 2017. Influence of Forest Harvest on Nitrate

Concentration in Temperate Streams-A meta-Analysis. Forests, 8(5), pp. 1-14. National Science Foundation, 2009. Earth's Biogeochemical Cycles, Once in Concert,

Falling Out Of Sync. [Online]

Available at: sciencedaily.com/releases/2009/08/090804071400.htm [Accessed 3 January 2020].

Ngatia, L., Grace III, J. M., Moriasi, D. & Taylor, R., 2018. Nitrogen and Phosphorus Eutrophication in Marine Ecosystems. Monitoring of Marine Pollution .

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12 Appendix

12.1 Detailed Overview of Wüstebach Instrumentation

Three runoff gauging stations have been installed in the research site to measure stream discharge and these can be seen in figure # above. All three runoff stations have been equipped with a V-notch weir for low flow measurements and a Parshall flume for normal to higher water flows (Bogena, et al., 2015). To gather runoff data, the two weir types are combined and weighted to represent accurate levels. A total of 8 piezometers have been installed in the site in order to assess groundwater levels across the catchment. In an effort to assess water quality, weekly grab samples are taken for chemical analyses at several locations along the Wüstebach stream (Bogena, et al., 2015). In addition to these locations, weekly grab samples are also taken from the main tributaries of the stream and the reference stream (see figure # above). These samples are taken back to the laboratory at the Jülich Forschungszentrum and analyzed in terms of water chemistry. Whilst weekly grab samples are being taken, water temperature, pH, redox potential and electrical conductivity are also measured manually in the field. Further information about water temperature, pH and electrical conductivity is gathered from multiprobes that have been installed at all runoff gauging stations. Fast changes in water chemistry that occur during discharge events is captured using auto-samplers that have also been installed at the runoff gauging stations.

To measure changes in meteorology, the main meteorological measurements are condensed around a 38 m high eddy tower that has been installed in the north western area of the catchment (see figure #). Precipitation measurements for the area are taken from the Kalterherberg meteorological station which is located 5km west of the catchment. Measurements taken from the tower, above the canopy, at a frequency of 20 Hz include: temperature; humidity; 3D wind vector; and 𝐶𝑂& concentration. Eddy covariance (EC) and radiation is also measured from the tower and a second EC station has been installed in the deforested area at 2.5 meters above the ground (Bogena, et al., 2015). Ground measurements are taken from the base of the tower in an area of 10 m by 10m and these include instrumentation to measure stem and surface temperature and snow depth. In three trenches surrounding the tower, soil heat flux is measured at a depth of 5 cm, and soil temperature and soil moisture is measured at depths ranging from 2 to 100 cm.

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Soil moisture monitoring is done through the wireless soil moisture sensor network SoilNet (Bogena, et al., 2015). 150 sensor units have been placed in the catchment that wirelessly provide soil information via several router devices to a central network coordinator unit (Bogena, et al., 2015). There are a total of 600 ECH20 EC-5 and 300 ECH20 5TE sensors installed in the Wüstebach catchment and they are buried at depth of 5, 20 and 50 cm (Bogena, et al., 2015). In addition to the sensors, a CRS-1000 cosmic-ray soil moisture probe is placed in the middle of the catchment. Water balance is assessed through six lysimeters installed in the catchment. This instrument measures water fluctuations in the soil-plant and atmosphere system (Bogena, et al., 2015). Additionally, these instruments also gather data on precipitation, evapotranspiration, and changes in soil water storage. To measure the sapflow fluxes of the research catchment, two sites were selected. One near the Wüstebach river as it is affected by groundwater fluctuations and the second on a hillslope as it is unaffected by changes in groundwater. At both sites, three trees are equipped with sapflow sensors to determine transpiration fluctuations of the Norway spruce trees.

Isotope monitoring is done by collecting weekly precipitation samples for isotopic analysis from the TERENO meteorological station Schöneseiffen. These samples are taken from a wet deposition collector, cooled in a refrigerator and tested in the laboratory using Isotope-Radio Mass Spectrometry (IRMS) (Bogena, et al., 2015). To measure soil respiration, in 2006 two transects were installed to measure respiration at 35 sites with 10 m between them. In 2008, this instrumentation was extended to include an additional 49 measurement points that are characterized by PVC collars that have been inserted into the forest floor. Weekly measurements of soil respiration, soil temperatures and soil moisture measurements are done (Bogena, et al., 2015). To monitor soil properties in the catchment, a series of soil sampling campaigns have been done starting one month prior to the deforestation at a total of 143 sampling sites. Tests done on these sites include bulk density, porosity, and soil hydraulic properties.

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