E
XPLORING THE INFLUENCE OF SUCCESSION IN WET COASTAL DUNE
SLACKS ON PIONEER SPECIES
L
IPARIS
L
OESELII
,
WITH FOCUS ON SOIL
ORGANIC MATTER AND NUTRIENT CONTENT ALONG AN AGE GRADIENT
.
Teuntje Parnassia Hollaar 10167617
Supervisor: Mw. dr. A.M. Kooijman
2
ndsupervisor: Dhr. dr. J.G.B. Oostermeijer
Institute for Interdisciplinairy Studies (IIS)
Institute for Biodiversity and Ecosystem Dynamics (IBED)
University of Amsterdam
2 Contents Introduction 3 Methods 4 Results 6 Discussion 13 Conclusion 16 Acknowledgements 16 Literature 17 Appendix 19 Abstract
In coastal areas, pioneer plant species, such as the perennial orchid Liparis Loeselii appear in early successional stages in wet base-rich dune slacks as well as in inland fens. These species depend on repeated formation of new dune slacks for new pioneer habitat. A decline of early successional species occurred since 1850, coincident with changed dune management that reduced dune dynamics. As countermeasures, since 1952 projects have been carried out to restore and improve habitats for these pioneer species.
This research explores the parameters that drive succession in wet coastal dune slacks on the Wadden island Texel, the Netherlands. It aims to explore the increase and decrease of the parameters organic matter, bulk density, carbon, nitrogen and the C/N ratio over time. This examination is a follow-up study of A. van der Craats (2011). Very similar measurement strategies and locations are used to make a comparison between the years. A comparison is made along an age gradient of the dune slacks, with the space for time substitution theory. The gathered data is also compared to the data of 2010 of the research of A. van der Craats (2011).
Field data is gathered in the Hors, here 44 plots distributed over nine dune slacks are sampled and described for plant presence and soil properties. The soil samples were examined in the lab using CNS analyses and oven-dried to calculate the bulk density, and subjected to statistical tests.
The results show that the organic matter content has significantly increased over time, as so did the amount of nitrogen and carbon in the soil. Accumulation of soil organic matter and the increase of nutrients in the soil, occur simultaneously with the change of an open to a dense vegetation
3 Introduction
The coastal dunes are generally considered to provide a rich habitat for many relatively rare plant species, owing to geomorphologic and hydrological gradients. This may be due to the fact that these dunes are one of the few nutrient-poor landscapes in the Netherlands (Grootjans e al., 2002), which gives an opportunity for pioneer species to flourish. Though, a decline in species-rich pioneer and early successional stages was caused by planting the species Ammophila arenaria to stabilize the system by dune management in 1950 (Arens and Geelen, 2006; van der Craats, 2011). Though, projects have been introduced to restore dune dynamics and with this early successional stages since 1952 (Grootjans et al., 2002). This research aims to contribute to the knowledge of the parameters thriving succession in coastal dune slacks. This knowledge provides information helpful for coastal management in the Dutch dunes, and could contribute to the restoration of dune dynamics and biodiversity in the pioneer stage.
A dune slack (as defined in Grootjans et al, 1991), is a low-lying area within the coastal dune system, here the water table is near the surface but also has a high seasonal fluctuation. One could distinguish two types of dune slacks; primary dune slacks and secondary dune slacks. Primary dune slacks are partially or completely cut off from influence of the sea. This results in desalinization of the soil within a few years. Secondary dune slacks are caused by intense sand-blowing in dune complexes (Grootjans et al., 1991). Primary succession in dune slack is divided into four phases (Grootjans et al., 1997). During the first phase microbial mats and algae dominate and accumulation or organic matter is low. In the second phase phanerograms colonize, which are adapted to low nutrient availability. During the third phase a moss layer of pleurocarpic bryophytes develops and invasion by tall grasses and shrubs. The fourth phase is characterized by a rapid accumulation of organic matter, partly due to acidification of the top layer, which leads to replacement of non-competitive plant species by shrubs and trees. In early successional stages, the soil in the dune slack is semi-bare and there is opportunity for pioneer species to establish in this environment. Though, over time abiotic and biotic factors change in the dune slacks, leading to more dense vegetated stages and a decline in pioneer species. Young dune slacks, although only scarcely covered by vegetation, show large variability in their species composition (Grootjans et al., 1998).
Successions in plant species on the Dutch Wadden islands are often caused by acidification, accumulation of organic matter and the increase of nutrients in the soil. This will occur simultaneously with the change of an open and short vegetation to a dense and tall vegetation cover (Grootjans et al., 1995). The increase in atmospheric deposition of nitrogen also contributes to succession of the soil (Kooijman and Besse, 2002). In this research the following parameters causing succession are explored: soil organic matter and the presence of the macro-nutrient nitrogen (N). Nutrients in young sandy dune soils are mostly absorbed to organic matter, therefore the organic matter influences the nutrient availability, concerning mostly the two macro-nutrients nitrogen and phosphorus. Both contribute to the formation of biomass (van der Craats, 2011), though phosphorus availability is high and the ecosystem is limited by the availability of nitrogen in the Wadden district (Kooijman et al., 1998). Therefore, this research does solely focus on nitrogen as macro-nutrient. Other important factors influencing succession are pH and the water table, which were explored in the research of Jongejans (2014). This results will be included in the discussion, because all variables influence each other.
The orchid Liparis Loeselii is a characteristic pioneer species of calcareous wet dune slacks (Westhoff and van Oosten, 1991). The species is indigenous of Europe and North America (FLORON, 2008), but is highly endangered in Europe. In the Netherlands the species is at the top of the Red List of Threatened Species. The pioneer is protected by several laws; the Habitats Directive introduced by the European Commission protects Liparis L. in Europe and the Flora- and Fauna law protects the species in the Netherlands. Liparis Loeselii is one of several pioneer species that prefers open vegetation and is therefore restricted to early successional stages (Odé and Bolier, 2003). The orchid is a pioneer species of nutrient poor, base rich and wet environments (van den Broeck, 2014). This species shows the health of the ecosystem and reacts quickly on abiotic changes in dune slacks. Therefore, Liparis Loeselii for fills the role as a key species of wet coastal dune slacks and provides an indicator for the success of current dune management (van der Craats, 2011).
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Figure 1: Map of the spatial distribution of the sampling plots of the dune slacks H1 to H9, on the Hors (van der Craats, 2011).
The field study is conducted at the Hors, the most South Western tip of the Wadden island Texel. There are several other locations where populations of Liparis Loeselii are present, though this is the perfect setting because the Hors is a dynamic area with little human interaction. The beach plains are expanding , due to accreting shoals, which is the main source of sand for the development of new dune slacks (Westhoff and Van Oosten, 1991). This is research is a follow-up study of the MSc research of A. van der Craats (2011) on a dataset gathered in 2010. So, the same measurement methods and sampling locations are used, for a reliable comparison of the parameters influencing soil succession between 2010 and 2014.
The research question of this study is: What are the main changes of organic matter content, nitrogen content,
carbon content and bulk density along an age gradient in coastal wet dune slacks?
This is divided in three sub questions:
1. What are the main differences of organic matter content and nutrient presence comparing the nine dune slacks?
2. What are the main differences of organic matter content and nutrient presence between 2010 and 2014? 3. How do the parameters influencing succession relate mutually?
Methods
Preparation
The shape files of van der Craats (2011) sampling locations in 2010 are adapted for use in the 2014 field campaign, using GIS software. Locations other than H1 to H9 are deleted. Also, only the locations where in 2010 Liparis Loeselii was present are used. The shape file is read in the Yuma 2 GPS device for use in the field.
Fieldwork
The field work is conducted in May 2014. It was not possible to find the exact same locations, due to faults in the use of the GPS system in 2010. Though, a specialist whom was with A. van der Craats as well, showed us the locations where the Liparis Loeselii is most likely to grow.
The sampling locations are spread out over 9 dune slacks, along an age gradient going from North East to South West (Figure 1). H1 is the oldest dune slack and H9 the youngest, as shown in Table 1. The difference of age of the populations of Liparis Loeselii is related to the age of the dune slacks and the stage of succession of the dune slack (van der Craats, 2011).
In 2010, the population of Liparis Loeselii at location H1 was considered extinct and at H9 the Liparis Loeselii was expected to appear. At all other locations (H2 to H8), Liparis Loeselii was present in 2010.
In total 44 plots are described, three soil samples are taken at each plot. Per location, four plots were sampled. At locations H4 and H6, eight plots are described, to allow taking the height gradient into account. For every
sampling plot a 1 by 1 meter square is marked and the vegetation is described giving every category a
percentages. The categories are: shrubs, herbs, mosses, bare sand and open water. Secondly, a drilling hole is made using an auger. The maximum depth augered was 0.5 meter. Due to the shallow groundwater levels, the depths of 2010 could often not been reached. The young soil profiles were described in horizons O, Ah, C1, C2 and C3. An O horizon is described where a peat layer was present, so more than 50% organic matter present. An Ah horizon is described when an organic horizon was present and the organic part is less than the amount of sand. C1 is the next horizon below the A or (if present) B horizon, comprising of the oxidized part of the C horizon that had no sign of mottling yet. Below the C1 (if present) the C2 horizon is found, a layer of both oxidation and reduction with oxidized matrix and clear mottling could usually be found. Last was the C3 horizon, this is a permanently reduced layer with a reduced matrix consisting of grey/blue sand and some mottling could be
5 present (van der Craats, 2011). The thickness of each horizon, including the organic horizon, is noted as well as is the colour using a Munssel scale. Also, the total depth of the profile and the maximum depth of roots are listed. At least, three soil samples are taken of the first 5 cm’s of the soil with a pF ring of 100 cm3 per sampling plot. These samples are stored in closed bags and kept at a cool temperature. After the fieldwork the samples were taken to the lab for chemical analysis.
Figure 2: Nine sampling locations. The sampling plots on the lower part of the slope are indicated as H4L and H6L, the higher part of the slope as H4H and H6H. “-L” indicates the presence of Liparis Loeselii in 2010. The quantity of sampling plots per sampling location are shown in the column “n”. *Not clear (secondary blow outs since 1953) stabilized in 1986, so average of the years is chosen. ** In 1996 in H6, still bare beach plane under influence of the sea (with some primary dunes) and in 1996 in H5 there are still Aeolian processes visible.
Lab work
The same methodology for chemical analyses of the soil samples is used as in A. van der Craats (2011), to ease comparison of the data.
The soil samples are weighted in gram at 2 decimal precision, after which they are dried in the oven at 70°C in an open bag for 72 hours. After this, the samples crushed by hand to remove the aggregates before sieving. The samples were sieved to remove material > 2 mm, such as small rootlets. This debris is described dispose. The sieved samples are weighed (correcting for the weight, of the bag that carried it). Now the dry weight of the sample is calculated as well as the bulk density, knowing the total volume per sample is 200 cm3 (Equation 1). For the analysis of C and N content, one spoon of the < 2 mm sieved sample was grinded for 5 minutes at 400 rpm. To determine the concentration of total carbon and nitrogen, a CNS analyzer (Elementar Vario EL tube) is used. Approximately 10-50 mg of grinded material is placed in a tin cup intended for mineral sample analysis and then folded until nothing can spill. Ten samples have a duplicate, and smaller folded tin cups with 7 mg
sulphanilic acid were placed before, in between and after the samples to calibrate the instrument. All tin cups are weighted with two decimals (mg) and their weights stored as input in the instrument. The tin cups are placed in the CNS analyzer where they will be burned individually at 1150 °C in a combustion chamber. The used output from the computer is a total percentage carbon and nitrogen and the C/N ratio. The average of the total
percentage carbon and nitrogen is calculated for the samples with a duplicate. Percentages were then converted into mmol/kg according to equation 2, with b=concentration of the measured parameter, and c=12 for the atomic mass of carbon and c=14 for the atomic mass of nitrogen.
The samples with high pH (Jongejans, 2014) have been tested for CaCO3 with a few drops of hydrochloric acid, to
confirm none was present.
Location Dune slack
formation finished
Code n
Dune slacks N-Nw of western Horsmeertje
1953 H1 4
Grauwe Gans valley 1969* H2-L 4
Kreeftepolder East 1977 H3-L 4
Kreeftepolder middle – wet 1977 H4L-L 4
Kreeftepolder middle – dry 1977 H4H-L 4
Secondary dune slacks north of Horsvallei
2000** H5-L 4
Horsvallei – wet 2000** H6L-L 4
Horstvallei – dry 2000** H6H-L 4
Saltier part Horsvallei 2000 H7-L 4
Western new dune slack 1996 H8-L 4
Future slack in Horsvallei 2005 H9 4
6 Equation 1: ]
Equation 2:
Results
Data preparation
The program Matlab 2012b was used for the statistical analysis and for the visualization of the results in graphs. Space delimited files were used as input of the program in the format of text files.
Locations comparison
To compare the difference in bulk density between dune slacks H1 to H9 an one-way ANOVA was applied, with sampling location as independent variable and bulk density as response variable. The H0: equal means between locations. The Ha: unequal means between locations. The correction factor being used is the default setting of Matlab, Tukey-Kramer. A parametric test could be used, because the variables are approximately normally distributed and difference in variance is not significant. The non-parametric Kruskal-Wallis test has been
conducted for the parameters carbon, nitrogen, C/N ratio and thickness of organic horizon, due to a significance difference in variance in the samples. Sampling locations are the independent variable and the parameters response variable, with the correction factor in the default mode (Scheffés method).
To find the exact locations which differ mutually the post hoc test multiple comparison is used. To prevent an overview of the summery statistics per variable, box-plots are created of the data obtained in 2010 and 2014. Correlation is calculated for all parameters and regression is performed where strong causal relationship is expected. The significance of the correlation was based on the Pearson product moment correlation coefficient, since the variables are linearly related.
Comparison 2010 and 2014 results
Due to a defect in the GPS system of 2010 one cannot be sure that the exact same locations are revisited in 2014. Therefore, independence is assumed between the locations of 2010 and 2014. And instead of a paired t-test, a two-sample t-test was conducted to make a comparison of the data from 2010 and 2014. Testing at a 0.05 significance level, for H0: equal means between the samples of 2010 and the samples of 2014, and Ha: unequal means between the samples of 2010 and 2014.
Space for time substitution
Linear regression is plotted for all variables along the age of the dune slacks, using the data of van der Craats (2011) and the data obtained in this research. The formation of the youngest dune slack (H9) was finished in 2005, so is 5 years old. The formation of the oldest dune slack (H1) was finished 1953, so is 61 years old. So, the data is plotted between the range of 5 to 61 years and the regression line shows the overall trend of the variables along an age gradient.
Carbon, Nitrogen and C/N ratio
Testing for equality between the nine dune slacks, the p-value of the Kruskal-Wallis was 0,0004, 0,0006 and 0,0036 respectively for carbon, nitrogen and C/N ratio. So, for all three variables the p-value is close to zero and the H0 hypotheses is rejected at a 0.05 significance level. Therefore at least one group differs significantly from the others. The multiple comparison test shows that location H1 differs significantly from younger locations for all three parameters, see Figure 6.
As shown in the box-plots the amount of carbon and nitrogen seems to increase over time, as well between 2010 and 2014, as along the age gradient of the dune slacks themselves (H1-H9). The mean carbon content has double in these four years, from 1.49 mmol/kg to 2.99 mmol/kg. Noteworthy, at location H8 the carbon content is
7 exactly the same in 2010 and 2014. The amount of nitrogen increased from a mean of 0.09 mmol/kg to 0.18 mmol/kg, so the mean amount of nitrogen doubled in these four years. Remarkable is that, just as the carbon content, the mean value of the nitrogen content has stayed almost the same for H8 (0.005 mmol/kg increase). In the relative young dune slacks the difference is small, because the carbon and nitrogen levels are close to zero. Comparing the data of 2010 to 2014, the locations H2 and H9 differ significantly between the years for the variables carbon and nitrogen. The outcome of the t-test proofs that the amount of carbon and nitrogen has increased significantly between 2010 and 2014 for the locations H2 and H9 (Figure 3 and 4). The C/N ratio seem to increase over time as well, again when comparing 2010 to 2014 and along the age gradient of H1 to H9. Performing the t-test for C/N ration leads to the conclusion that the ratio has increased significantly for the locations H8 and H9 between 2010 and 2014 (Figure 5).
As shown in the Figures 6, 7 and 8 of linear regression of nitrogen, carbon and the C/N ratio along a time gradient, all three variables increase over time. The nitrogen content increases slowly over time, though the values stay below 0.35 mmol/kg. Especially in the early years the observed values match the linear fitted line, the deviation is larger when the age of the dune slacks increases. The carbon content rises over the years, showing a steep increase. The deviation of the observed data with the fitted line is small for all years. The C/N ratio has a start value of about 14 and increases to about 18 in year 61. The observed data of the C/N ratio shows a large deviation from this linear line, the actual minimum and maximum values do differ.
Carbon and nitrogen have a strong positive correlation, with a Rho of 0.99 and a p-value of approximately zero. The relation between carbon and nitrogen is retrieved by the use of a regression line. The relation between carbon and nitrogen is linear. The derived equation of regression between carbon and nitrogen is:
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Tables and figures
Two-sample t-test: Carbon [%]
Location Null hypothesis p-value
H1 Accepted 0.3304 H2 Rejected 0.0220 H3 Accepted 0.0926 H4 Accepted 0.4373 H5 Accepted 0.2101 H6 Accepted 0.0687 H7 Accepted 0.2088 H8 Accepted 1 H9 Rejected 5.4906e-04 Carbon content Location 1 Location 2 H1 H8 H1 H9 H3 H8 H3 H9 Nitrogen content Location 1 Location 2 H1 H8 H1 H9 H3 H8 H3 H9 C/N ratio Location 1 Location 2 H1 H8 H1 H9 H3 H8 H3 H9
Two-sample t-test: Nitrogen [%]
Location Null hypothesis p-value
H1 Accepted 0.3180 H2 Rejected 0.0171 H3 Accepted 0.0557 H4 Accepted 0.4034 H5 Accepted 0.2103 H6 Accepted 0.0577 H7 Accepted 0.2465 H8 Accepted 0.6480 H9 Rejected 0.0054
Two-sample t-test: C/N ratio
Location Null hypothesis p-value
H1 Accepted 0.9148 H2 Accepted 0.8669 H3 Accepted 0.2896 H4 Accepted 0.8835 H5 Accepted 0.2561 H6 Accepted 0.2587 H7 Accepted 0.7551 H8 Rejected 7.3097e-04 H9 Rejected 0.0306
Figure 4: Output of two-sample t-test of nitrogen content in the topsoil, comparing data gathered in 2010 (van der Craats, 2011) and 2014.
Figure 3: Output of two-sample t-test of carbon content in the topsoil, comparing data gathered in 2010 (van der Craats, 2011) and 2014.
Figure 5: Output of two-sample t-test of the C/N ratio, comparing data gathered in 2010 (van der Craats, 2011) and 2014.
Figure 6: Shows the locations that difer from each other at a significance level of 0.05 using a two-sample t-test.
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Figure 7: Box plot of the carbon content per dune slack. Figure 8: Box plot of the nitrogen content per dune slack. Showing summary statistics of the data of 2010 and 2014. Showing summary statistics of the data of 2010 and 2014.
Figure 9: Box plot of the C/N ratio per dune slack. Figure 10: Linear regression of C/N ratio between the years Showing summary statistics of the data of 2010 and 2011. 1953 to 2005.
Figure 11: Linear regression of nitrogen of dune
slacks formed between the years 1953 to 2005, measured in 2010 (van der Craats, 2011) and 2014.
Figure 12: Linear regression of carbon of dunes slacks formed between the years 1953 to 2005, measured in 2010 (van der Craats, 2011) and 2014.
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Bulk density and organic horizon
As shown in the box-plot (Figure 17), the bulk density seems to decrease over time. This decrease is seen when comparing 2010 to 2014, but also along the age gradient of the nine locations (H1-H9). The bulk density decreases along the age gradient of the nine dune slack, 1953 to 2005. Comparing the bulk density of the dune slacks mutually results in a p-value of 4.6369e-09. Therefore, H0 is rejected at a 0,05 significance level, meaning that at least one sampling side contains a significantly different bulk density compared to the others. The multiple comparison test shows that 17 pairs differ, as shown in Figure 15. Simultaneously, the thickness of the organic horizon increases along this age gradient (Figure 19 and 20). The organic horizon seems to increase over time as shown in Figure 18. The Kruskal-Wallis test results in a significant difference between the oldest and youngest dune slacks (Figure 16). shows that location 1-8 1-9 3-9 significantly differ from each other.
Comparing the bulk density per location between 2010 and 2014, leads to the conclusion that location H2 and H3 differ significantly in time. So the bulk density decrease significantly in H2 and H3 in 2014 compared to 2010. Comparing the thickness of the organic horizon between 2010 and 2014, leads to the conclusion that locations H2 and H9 significantly differ between the years.
Bulk density has a moderate strong correlation with carbon content as well as nitrogen content, with Rho’s of respectively -0,72 and -0,76 and both p-values are approximately zero. The correlation between bulk density and the C/N ratio is moderately strong and negative, with a Rho of -0,57 and a p-value of approximately zero. The equation derived of the regression line between bulk density and carbon and nitrogen is:
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Tables and figures (continued)
Two-sample t-test: Bulk density [g/cm3]
Location Null hypothesis p-value
H1 Accepted 0.8751 H2 Rejected 0.0065 H3 Rejected 0.0235 H4 Accepted 0.1289 H5 Accepted 0.4982 H6 Accepted 0.1232 H7 Accepted 0.2769 H8 Accepted 0.7700 H9 Accepted 0.5689
Figure 13: Output of Two-sample t-test of bulk density of the first 5 cm’s of the soil, comparing data gathered in 2010 (van der Craats, 2011) and 2014.
Two-sample t-test: Organic Horizon [cm]
Location Null hypothesis p-value
H1 Accepted 0.5074 H2 Rejected 0 H3 Accepted 0.1036 H4 Accepted 0.8303 H5 Accepted 0.0941 H6 Accepted 0.1748 H7 Accepted 0.3719 H8 Accepted 0.3359 H9 Rejected 0
Table 14: Output of Two-sample t-test of thickness of organic horizon, comparing 2010 (van der Craats, 2011) and 2014.
Bulk density [g/cm3] Location 1 Location 2 H1 H4 H1 H5 H1 H7 H1 H8 H1 H9 H2 H8 H2 H9 H3 H4 H3 H5 H3 H7 H3 H8 H3 H9 H4 H8 H4 H9 H6 H8 H6 H9 H7 H8 Organic horizon [cm] Location 1 Location 2 H1 H8 H1 H9 H3 H9
Figure 16: Shows the locations that significantly differ from each other in 2014, concerning the thickness of the organic horizon.
Figure 15: Shows the bulk densities that significant differ from each other.
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Vegetation
Test have been performed to compare the diversity of vegetation and the total cover of vegetation between 2010 and 2014. Though, because not the exact same locations in 2014 were found as in 2010 this comparison does not lead to any results that are significant.
An comparison between the nine dune slacks leads to the conclusion that no significant difference is found between the nine locations, with a p-value of 0,1743 H0 cannot be rejected.
There is no significant correlation found for total vegetation cover and bulk density, carbon and nitrogen.
Figure 18: Box plot of the thickness of the organic horizon per dune slack. Showing summary statistics of the data of 2010 and 2011.
Figure 19: Linear regression plot of bulk density along an age gradient of dune slacks formatted between 1953 to 2005, measured in 2010 (van der Craats, 2011) and 2014.
Figure 20: Linear regression plot of thickness of organic horizon along an age gradient of dune slacks formatted between 1953 to 2005, measured in 2010 (van der Craats, 2011) and 2014.
Figure 17: Box plot of the thickness of the organic horizon per dune slack location. Showing summary statistics of the data of 2010 and 2011.
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Figure 21: Shows the diversity and die percentage cover of vegetation per dune slack in 2014.
Discussion
1. What are the main differences of organic matter content and nutrient presence comparing the nine dune slacks?
The bulk density of soils greatly depends on the compaction of the soil. Solid quartz has a density of 2.65 g/cm3, though dried mineral soils have a bulk density around 1 to 1.6 g/cm3 (Brown & Wherret, 2014). Soils rich in organic matter often have a lower dry bulk density, for example peaty soils can have densities of less than 0.5 g/cm3, due to a relative low compaction of the material. The mean value of bulk density of the nine dune slacks was 0.93 g/cm3, so quite low. The lowest bulk density (0.17 g/cm3) was found in the oldest sampling location H1, and the highest bulk density (1.53 g/cm3) in H8, which is the youngest location together with H9. This is a result that was expected, because the younger the dune slack, the less organic matter has accumulated and the more sand still exists in the top 5 cm’s.
Carbon is fixed by the process of photosynthesis in the plants, and this carbon is transferred to the soil via dead plant material, such as roots and leaves. The amount of carbon in the soil is thus generally related to the amount of vegetation on that soil, and increases with age. Therefore, the amount of carbon in the younger dune soils with low vegetation cover was relatively low; with values of 0.20 mmol/kg in the youngest dune slack H9. Low content of organic matter and slow pedogenesis are mainly caused by low productivity during the first years of vegetation development in dune slacks (Grootjans et al., 1998). In contrast, more mature soils such as H1, with high
vegetation cover, had a relatively high amount of carbon (23.64 mmol/kg) present in the system. Carbon is an important compound of organic matter and comprises about 58% of the organic matter (Bodemacademie, 2014). The rate of decomposition of organic matter is greatly influenced by the acidity of the soil, a decrease in pH slows down the rate of decomposition. Indeed the research of Jongejans (2014), shows the pH to decrease from the younger to the older of the nine dune slacks.
Nitrogen in the atmosphere is the ultimate source of soil nitrogen. Nitrogen could enter the soil trough several processes, rainfall, plant residues, nitrogen fixation by soil micro-organisms, animal manures and commercial fertilizers (Barbarick, 2014). Nitrogen may be lost from the soil by plant removal, volatilization, leaching or erosion. The amount of nitrogen in the soil may affect the rate of primary production and decomposition (Galloway et al., 2004). Terrestrial plants are often limited by the availability of nitrogen in the soil (Agren et al., 2012). Low availability of nitrogen in the soil results in a reduction in biomass, and therefore in a reduction of carbon and organic matter. More mature soils as H1 with a high vegetation cover and high amount of soil organic matter contain a larger amount of nitrogen in the soil. The minimum amount of nitrogen found in the dune sequence was 0.02 mmol/kg, in the two youngest locations, H8 and H9. The amount of nitrogen increased over time, to the maximum value of 1.23 mmol/kg in the oldest dune slack H1.
An increase of carbon and nitrogen will lead to an overall increase of the concentration and increase in the thickness of the organic horizon. This was supported by the clear increase in the thickness of the O/Ah from 0.5 cm in the youngest and 13-17 cm in the oldest dune slack, which thickened over time.
14 The range of the C/N ratio, which ranged from 10.3 to 19.5, points to an origin of the dead plant material from terrestrial plants (Cornell, 1996). When the proportion of nitrogen is too high, the surrounding soil may go anaerobic. The proportion of nitrogen is higher in the younger dune slacks; the lowest value of the C/N ratio (10.29) is found at the youngest dune slack, H9. High values of the C/N ratio are given for the oldest dune slack H1, which leads to the highest mean value per dune slack. Though, due to large variance between sampling plots of the location H6, the maximum value is found for this dune slack. Overall the C/N ratio increases along the age gradient of the nine dune slacks, therefore the relative amount of nitrogen decreases relative to carbon content over time.
Fresh plant material has a higher C/N ratio compared to dead biomass, because it contains a higher amount of carbon. This amount of carbon decreases when the process of decomposition is further along, due to evaporation of CO2 in to the atmosphere. This does expect that the C/N ratio decreases over time, though in this case it is the other way around. This might be caused by the existence of microbial mats in young dune slacks. Microbial mats exists of layers of benthic filamentous cyanobacteria and algae (Lammerts et al., 1995), these cyanobacteria are able to fix nitrogen (Stal, 1985). The optimum conditions for microbial mats to develop is on bare soils which are not restricted by water supply (Hofmann, 1942). So, microbial mats are likely to influence the C/N ratio in the young dune slacks. When the abiotic and biotic factors change over time, the microbial mats are no longer able to survive and the C/N ratio will increase until original state is retained. Dune slacks H1 to H9 are all relatively young dune slacks, comparing the oldest (H1 –H3) to more mature soils the C/N ratio probably drops again.
Also, the C/N ratio is influenced by the acidity of the soil. Acid soils with low pH usually contain greater amounts of organic matter, because microorganisms become less active as soil acidity increases (Lines-Kelley, 1993). The pH in the dune slacks decreases between 2010 and 2014 (Jongejans, 2014), therefore the decomposition of the litter increases and the amount of organic material in the soil increases. For this reason the C/N ratio did not drop as much as when the rate of decomposition was not influenced by a relatively high acidity levels.
Overall, the organic horizon, carbon and nitrogen content and the C/N ratio all increased over the time gradient along the nine dune slacks. This increase in organic matter led to a decrease of the bulk density along this time gradient.
2. What are the main differences of organic matter content and nutrient presence between 2010 and 2014? The bulk density decreases between 2010 and 2014, with a significance decrease of the bulk density at two of the more mature dune slacks, H2 and H3. The mean difference of -0.18 g/cm3 in bulk density between the years also reflects this decrease. . Soil organic matter has a higher porosity then dune sand, due to higher activity of soil fauna in the organic horizon, and therefore the bulk density decreases when the amount of organic matter increases. This corresponds with the four phases of primary succession as described in Grootjans (1997), with low accumulation of organic matter in the first phase and rapid accumulation of organic matter in the final phase, due to acidification of the top layer.
The mean carbon content almost doubled (1.49 mmol/kg to 2.99 mmol/kg) between 2010 and 2014, so carbon content rises in these four years. As soil carbon makes up for about 58% of the organic matter, an increase of carbon along the age gradient was expected. The nitrogen content also doubled in these four years (0.09
mmol/kg to 0.18 (mmol/kg). The accumulation of nitrogen and carbon trough time is also confirmed by the study of Knops & Tilman (2000). The increase of carbon and nitrogen could be due to an overall increase of the carbon and nitrogen concentration, or the organic horizon has thickened over time. The results show it is the latter, the thickness of the organic horizon has increased between 2010 and 2014. An increase in the thickness of the O and Ah could be explained by the increase in vegetation during the four phases of primary succession (Grootjans et al., 1997), so more dead plant material is available for decomposition.
The C/N ratio in the dune slacks could be under influence of microbial mats, if the environmental conditions allow the mats to grow and develop quickly. If this is the case, the relative N concentration is higher in younger dune slacks as in more mature dune slacks. The C/N ratio has increased between the years 2010 and 2014, so the relative amount nitrogen has decreased over these years, suggesting the influence of microbial mats. The highest increase of the C/N ratio is found at the two youngest dune slack (H8 and H9), which fits the assumption of microbial mats in the first phase of succession when bare ground is not scarce.
15
3. How do the parameters influencing succession relate mutually?
A strong positive correlation between carbon and nitrogen is in accord with the research of Knops et al. (2000), which states that the rate of carbon accumulation was controlled by the rate of nitrogen accumulation. Nitrogen and carbon both strongly depend on the vegetation cover, which increases during the four phases of succession, and both increase with age.
Carbon and nitrogen both have a strong negative correlation with the soil bulk density, this could be explained by the fact that carbon comprises about 58% of the organic matter, and the macro-nutrient nitrogen also
contributes to the organic content. Moreover, nitrogen is often limiting plant growth in temperate ecosystems and therefore extremely important to enable plant growth. Therefore, when the carbon and nitrogen content increases, the organic content in the soil increases. And as described above, organic matter is less dense then the dune sand, so bulk density decreases.
Bulk density and the C/N ratio show a strong negative correlation, suggesting that the relative amount of carbon to nitrogen increases when the organic horizon increases. This could be explained by the presence of benthic mats consisting of nitrogen fixing cyanobacteria in younger dune slacks. These bacterial mats are only able to dominate during the first phase of primary succession, when the organic matter content is low (Grootjans, 1997). Therefore, the C/N ratio is likely to increase during later phases of succession at more mature dune slacks. The rate of organic decomposition is very low in water saturated soils, due to a lack of oxygen for the
microorganisms necessary for the breakdown of organic matter. Soils formed from waterlogged organic matter contain a high percentage of organic matter and probably a peaty layer (O horizon) (Lines-Kelley, 2004). The water table differs strongly between the nine dune slacks, and increases with age of the dune slack (Jongejans, 2014). This corresponds with the thickness of the organic horizon, which increases over time as well.
Organic matter content is of influence on the pH, the accumulation of organic matter leads to soil acidification, so a decrease in pH (Ritchie & Dolling, 1985). Research of Jongejans (2014) shows that the pH decreases along an age gradient. The pH and organic content strongly relate, when the amount of organic matter increases the soil acidity increases. The strong negative correlation found between pH and thickness of the organic horizon is expected, because organic matter is a source of acidity.
Vegetation cover does not show any relation with bulk density, carbon or nitrogen. Though, one would expect a strong causal relationship, because the low primary productivity is the main cause of the low content of organic matter during the first year of vegetation development in dune slacks (Grootjans et al, 1997). This lack of correlation between vegetation cover and the other variables could be explained by the used methods, a
personal estimation of the vegetation cover is not very accurate. First of all, it is depended up on the person who makes the estimation in the field. So, there could be a difference in personal view when comparing the data of 2010 and 2014 and when comparing the dune slacks in 2014 mistakes in the estimation could be made, due to lack of experience. Secondly, the locations are not exactly the same as in 2010, so a one cannot really compare the vegetation cover of 2010 and 2014.
The main factors controlling the soil development and succession rate are primary production of the ecosystem, rate of decomposition of the organic matter and recycling of the nutrients within the ecosystem (Grootjans et al, 1997). For pioneer species as Liparis Loeselii, nutrient poor environments are most suitable, so soils with a relatively high bulk density and low carbon and nitrogen content are favorable. The finding of van der Craats (2011), that the bulk density decreases with species population age complements this, because the species population age has a positive correlation with dune slack age. Therefore, the Liparis Loeselii is most likely to establish on young dune slacks (as H8 and H9), where the organic content is low to zero and no competition for light and space is with other species.
16 Conclusion
Carbon, nitrogen, C/N ratio and the organic matter all increase along an age gradient, this is clearly shown in the comparison of the data of 2010 and 2014 and also when comparing the nine dune slacks of which the oldest was formed in 1953 and the youngest in 2005. The bulk density decreases along with this increase of the organic horizon, because organic matter is less dense than the original dune sands.
Nitrogen and carbon strongly correlate and behave similar over time. The C/N ratio is relatively low in the
younger dune slacks, due to nitrogen fixing cyanobacteria in microbial mats, that only dominate in the first phase of succession. The increase of organic matter might be enhanced by the increased levels of the water table in 2014, because the decomposition rate of organic matter decreases when the soils are water-logged. The increase in organic matter also corresponds to the decrease in pH seen over time, organic matter being a source of acidity. All parameters indicate later phases of primary succession in the more mature soils, here levels of nitrogen and carbon are at a maximum and the organic horizon is thick. On the youngest dune slacks bare ground is still available for pioneer species to establish, also the nutrient content is low and no thick organic horizon has developed. Therefore, dune slacks H8 and H9 are the most favorable habitats for pioneer species as Liparis Loeselii to establish in 2014.
Acknowledgements
I would like to thank dhr. L. Hoitinga for his guidance and time in the laboratory and Mw. dr. A.M. Kooijman for her mentoring and help during the whole project. And my gratitude goes out to L.L. Jongejans, who I worked side by side with during the field and lab study.
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19 Appendix
Content
Coordinates sampling plots
Field parameters
Thickness organic horizon 2010 and 2014
Raw data bulk density
Raw data CNS analyses
Coordinates sampling plots
Samplin g Location Plot Number Coordinates N E H1 38 53,006 92 4,7393 72 H1 39 53,006 94 4,7400 5 H1 40 53,006 75 4,7417 H1 41 53,006 7 4,7421 44 H2 30 53,004 99 4,7302 89 H2 31 53,004 97 4,7303 75 H2 32 53,004 9 4,7303 11 H2 33 53,004 86 4,7297 03 H3 1 53,000 81 4,7412 39 H3 2 53,000 83 4,7408 86 H3 3 53,000 92 4,7397 36 H3 7 53,001 44 4,7379 14 H4 70 53,003 4 4,7299 86 H4 71 53,003 44 4,7297 72 H4 72 53,003 48 4,7297 83 H4 73 53,003 48 4,7296 56
20
Table 1: During the fieldwork difficulty was found due to a default in the GPS system used in 2011. The GPS coordinates did not match up with the locations the specialist though that would be the ones. This year the locations were marked with 2 types of markers and a more precise GPS system was used (Yuma 2). Also, the coordinates are precisely noted in the appendix. So, when future research is carried out the exact same locations should be possible to find.
H4 74 53,003 54 4,7298 64 H4 75 53,003 51 4,7299 03 H4 76 53,003 49 4,7299 31 H4 77 53,003 39 4,7298 36 H5 65 53,000 41 4,7458 H5 64 53,000 27 4,7468 44 H5 62 53,000 16 4,7449 75 H5 63 53,000 13 4,7474 86 H6 42 53,000 03 4,7458 81 H6 43 52,999 97 4,7453 97 H6 44 52,999 98 4,7454 08 H6 47 52,999 98 4,7452 92 H6 48 52,999 95 4,7452 86 H6 51 52,999 99 4,7456 14 H6 52 52,999 97 4,7456 25 H6 56 53,000 02 4,7458 92 H7 22 52,998 48 4,7524 19 H7 23 52,998 82 4,7520 17 H7 24 52,998 96 4,7517 14 H7 25 52,999 24 4,7515 14 H8 10 53,002 47 4,7207 78 H8 11 53,002 52 4,7207 5 H8 14 53,002 94 4,7201 94 H8 16 53,003 93 4,7190 44 H9 26 52,997 4 4,7481 94 H9 27 52,997 36 4,7479 72 H9 28 52,997 31 4,7482 5 H9 29 52,997 33 4,7482 78
21 Field parameters Samp ling Location P lot Nr Sh rub cover H erb cover M oss cover Ba re sand cover Op en water cover Water table (uncorr.) Wat er table (corr.) C-2 hor. upper lim. C-3 hor. upper lim. [% ] [ %] [ %] [% ] [% ] [cm] [cm] [cm] [cm] H1 3 8 5 30 2 0 0 40 -6,5 -8 10 not at 30 H1 3 9 20 45 1 5 0 20 -6,5 -8 15 not at 44 H1 4 0 10 55 1 0 5 20 -3 -4,5 17 not at 25 H1 4 1 20 60 1 5 5 0 -3 -3,5 - 10 of 44 H2 3 0 0 20 5 25 50 -1,5 -2 9 not at 17 H2 3 1 0 10 0 0 90 8 7,5 5 not at 20 H2 3 2 0 15 4 0 35 10 -1 -1,5 9 not at 24 H2 3 3 10 5 7 0 0 15 -2 -2,5 - 5 of 18 H3 1 20 50 2 5 5 0 -5,5 -5,5 ??? H3 2 50 15 3 0 5 0 -5 -5 9 not at 20 H3 3 20 20 3 0 0 30 -1 -1 8 not at 21 H3 7 10 25 6 0 5 0 -5 -5 9,5 20 H4 7 0 10 5 0 35 0 -3,5 -3,5 11 22 H4 7 1 0 10 0 0 90 9 8,5 6 12 H4 7 2 0 15 0 0 85 5,5 5,5 7 23 H4 7 3 0 35 0 0 65 11 11 ??? H4 7 4 0 85 5 10 0 -17,5 -18 5 not at 35 H4 7 5 0 20 0 80 0 -7,5 -8 11,5 not at 25 H4 7 6 0 70 1 0 20 0 -10 -10,5 7,5 15
Table 1: The coordinates of the exact locations that were sampled during this project.
22 H4 7 7 10 15 5 70 0 -6 -6 10,5 H5 6 5 5 45 0 15 35 -9 -9 3,5 12 H5 6 4 8 72 5 15 0 -14 -14 1,5 not at 24 H5 6 2 65 20 2 5 10 0 -2 -2 - 4 H5 6 3 15 50 3 0 5 0 -1,5 -1,5 6 not at 25 H6 4 2 5 75 1 0 5 0 -5,5 -5,5 9,5 not at 24 H6 4 3 5 60 5 25 5 -5 -5 - 9 H6 4 4 40 30 2 0 10 0 -28 -28 9 not at 47 H6 4 7 15 28 5 5 2 0 -27 -27 9,5 not at 43 H6 4 8 5 52 5 38 0 -5 -5 7,5 17 H6 5 1 5 45 0 50 0 -2,5 -2,5 13 25 H6 5 2 20 40 4 0 0 0 -17 -17 5 23 H6 5 6 10 30 6 0 0 0 -30 -30 14,5 not at 41 H7 2 2 0 45 0 35 20 -4 -4 - 4,5 H7 2 3 60 10 1 5 5 0 -6,5 -6,5 4 not at 20 H7 2 4 30 58 2 10 0 -19,5 -19,5 1,5 not at 20 H7 2 5 25 55 1 0 5 5 -0,5 -0,5 6,5 not at 20 H8 1 0 0 60 3 0 10 0 -24 -27 7 22 H8 1 1 0 60 3 0 10 0 -24 -27 7 22 H8 1 4 0 15 6 5 20 0 -29,5 -32,5 6 24 H8 1 6 0 60 3 0 10 0 -34 -37 6 18 H9 2 6 0 95 0 5 0 -9,5 -12,5 2 20 H9 2 7 0 95 0 5 0 -6 -9 0,5 11,5 H9 2 8 0 90 0 10 0 -7 -10 - 0,5 H9 2 9 0 90 0 10 0 -4 -7 0,5 15,5
Tabel 2: Not at: bore hole not deep enough to reach the C3 horizon. Vegetation cover per category is in percentage. And the measured depth of the water table and thickness of horizon are in cm.
Thickness organic horizon
Sampling Location Plot Nr Organischelaag 2014 [cm]
OrganischeLaag 2010 [cm]
23 H1 39 15 13 H1 40 17 10 H1 41 10 10,5 H2 30 9 6 H2 31 5 4 H2 32 9 2 H2 33 6 H3 1 8 5 H3 2 9,5 4 H3 3 11 9 H3 7 6 4,5 H4 70 7 2 H4 71 3 H4 72 5 3 H4 73 9 3 H4 74 7,5 17 H4 75 2,5 5 H4 76 3,5 5 H4 77 5 4 H5 65 4 3 H5 64 3 5,5 H5 62 9,5 0 H5 63 9 0 H6 42 9 9 H6 43 9,5 3 H6 44 7,5 7 H6 47 13 4 H6 48 5 2 H6 51 3 5 H6 52 4,5 5 H6 56 4 4 H7 22 1,5 5,5 H7 23 6,5 5 H7 24 1,5 1,5 H7 25 1,5 5 H8 10 2,5 1,5 H8 11 1,5 6 H8 14 1 0 H8 16 2,5 8 H9 26 0,5 0 H9 27 0,5 0 H9 28 0,5 0 H9 29 0,5 0
24 Raw data bulk density 2014
Location GPS Droog gewicht met zakje [g] Volume [cm3] Bulk Density [g/cm3]
H1 38 145,97 200 0,72985 H1 39 143,72 200 0,7186 H1 40 64,44 200 0,3222 H1 41 34,15 200 0,17075 H2 30 132,01 200 0,66005 H2 31 182,65 200 0,91325 H2 32 150 200 0,75 H2 33 186,45 200 0,93225 H3 1 117,96 200 0,5898 H3 2 68 200 0,34 H3 3 88,33 200 0,44165 H3 7 80 200 0,4 H4 70 253,53 200 1,26765 H4 71 183,3 200 0,9165 H4 72 282,73 200 1,41365 H4 73 273 200 1,365 H4 74 127,68 200 0,6384 H4 75 97,6 200 0,488 H4 76 74,19 200 0,37095 H4 77 164,11 200 0,82055 H5 101 265,24 200 1,3262 H5 102 292,06 200 1,4603 H5 62 234,42 200 1,1721 H5 103 170,58 200 0,8529 H6 42 47,72 200 0,2386 H6 43 133,03 200 0,66515 H6 44 221,97 200 1,10985 H6 47 212,45 200 1,06225 H6 48 112,26 200 0,5613 H6 51 80,28 200 0,4014 H6 52 190,81 200 0,95405 H6 56 235,98 200 1,1799 H7 22 206,18 200 1,0309 H7 23 168,94 200 0,8447 H7 24 256,06 200 1,2803 H7 25 194,41 200 0,97205 H8 10 290,8 200 1,454 H8 11 268,64 200 1,3432 H8 14 306 200 1,53 H8 16 300 200 1,5 H9 26 284,77 200 1,42385 H9 27 283,98 200 1,4199 H9 28 274,51 200 1,37255
25
H9 29 301,63 200 1,50815
Table 4: Raw bulk density data. The dry weight is divided by the total volume (200 cm3) to calculate the bulk density.
Raw data CNS analyses with correction
Name Weight [mg] N [%] C [%] N Area C Area CN ratio method N factor C factor
RunIn 1 0 0 0 0 0 5mg90s 1 1 sulfanilic acid 9,1 8,09 41,61 18 800 68 521 5,14 5mg90s 1,0253 1,0239 sulfanilic acid 7,09 7,96 41,14 14 750 54 122 5,17 5mg90s 1 1 sulfanilic acid 7,01 8,09 41,61 14 446 53 191 5,14 5mg90s 1,0259 1,0176 sulfanilic acid 11,53 8,09 41,61 23 729 86 488 5,14 5mg90s 1,0304 1,0262 sulfanilic acid 9,02 8,09 41,61 18 510 68 094 5,14 5mg90s 1,0321 1,0213 sulfanilic acid 9,45 8,09 41,61 19 576 71 547 5,14 5mg90s 1,0228 1,018 sulfanilic acid 8,39 7,7 39,99 16 909 62 204 5,19 5mg90s 1 1 sulfanilic acid 10,96 8,09 41,61 22 395 81 671 5,14 5mg90s 1,0376 1,0334 Blnk 1 0 0 0 81 0 5mg90s 1,029 1,0234 2014/TPH/01 69,2 0,24 4,29 4 169 53 793 17,8 5mg90s 1,029 1,0234 2014/TPH/01 43,48 0,23 4,16 2 471 32 880 18,35 5mg90s 1,029 1,0234 2014/TPH/02 41,28 0,22 4 2 279 30 001 18,13 5mg90s 1,029 1,0234 2014/TPH/03 30,03 0,54 10,37 4 021 56 434 19,38 5mg90s 1,029 1,0234 2014/TPH/04 67,32 1,23 23,61 21 029 284 743 19,25 5mg90s 1,029 1,0234 2014/TPH/04 46,41 1,23 23,67 14 471 197 259 19,28 5mg90s 1,029 1,0234 2014/TPH/05 73,66 0,27 4,26 4 986 56 916 15,73 5mg90s 1,029 1,0234 2014/TPH/06 70,82 0,15 2,11 2 646 27 199 14,17 5mg90s 1,029 1,0234 2014/TPH/07 65,87 0,25 3,97 4 168 47 486 15,7 5mg90s 1,029 1,0234 2014/TPH/08 41,45 0,15 2,35 1 513 17 710 16 5mg90s 1,029 1,0234 2014/TPH/09 57,13 0,26 4,27 3 698 44 274 16,53 5mg90s 1,029 1,0234 2014/TPH/09 60,82 0,26 4,3 3 963 47 425 16,51 5mg90s 1,029 1,0234 2014/TPH/10 58 0,41 6,48 5 979 67 996 15,75 5mg90s 1,029 1,0234 2014/TPH/11 53,48 0,16 2,55 2 206 24 843 15,49 5mg90s 1,029 1,0234 2014/TPH/12 47,28 0,36 6,68 4 191 57 221 18,72 5mg90s 1,029 1,0234 2014/TPH/13 56,77 0,07 1,15 959 11 920 16,86 5mg90s 1,029 1,0234 2014/TPH/13 85,72 0,07 1,13 1 458 17 657 16,54 5mg90s 1,029 1,0234 2014/TPH/14 77,43 0,09 1,44 1 644 20 297 16,91 5mg90s 1,029 1,0234 2014/TPH/15 71,82 0,03 0,46 578 6 051 14,07 5mg90s 1,029 1,0234 2014/TPH/16 54,39 0,04 0,63 515 6 242 16,26 5mg90s 1,029 1,0234 2014/TPH/16 69,52 0,04 0,64 736 8 123 14,88 5mg90s 1,029 1,0234 2014/TPH/17 56,03 0,33 4,77 4 550 48 458 14,62 5mg90s 1,029 1,0234 2014/TPH/18 50,5 0,38 5,5 4 746 50 371 14,59 5mg90s 1,029 1,0234 2014/TPH/19 79,1 0,61 9 12 273 128 363 14,72 5mg90s 1,029 1,0234 2014/TPH/19 60,69 0,62 9,04 9 570 99 104 14,5 5mg90s 1,029 1,0234 2014/TPH/20 47,02 0,03 0,5 387 4 275 14,77 5mg90s 1,029 1,0234 2014/TPH/21 43,06 0,17 3,08 1 824 24 159 18,18 5mg90s 1,029 1,0234 2014/TPH/22 73,26 0,04 0,62 645 8 221 17,14 5mg90s 1,029 1,0234 2014/TPH/22 39,78 0,02 0,34 230 2 429 13,93 5mg90s 1,029 1,0234 2014/TPH/23 87,47 0,05 0,69 1 051 11 052 14,27 5mg90s 1,029 1,0234 2014/TPH/24 31,43 0,06 1,13 470 6 453 18,37 5mg90s 1,029 1,0234 2014/TPH/25 46,4 0,48 7 5 565 58 871 14,62 5mg90s 1,029 1,0234 2014/TPH/25 35,96 0,47 7,08 4 205 46 190 15,04 5mg90s 1,029 1,0234 2014/TPH/26 58,94 0,21 3,36 3 086 36 026 16,12 5mg90s 1,029 1,0234 2014/TPH/27 33,93 0,05 0,87 452 5 380 15,94 5mg90s 1,029 1,0234 2014/TPH/28 57,93 0,08 1,32 1 217 13 939 15,6 5mg90s 1,029 1,0234 2014/TPH/29 56,54 0,21 3,42 3 021 35 096 16,04 5mg90s 1,029 1,0234
26 2014/TPH/30 50,33 0,35 5,48 4 414 50 062 15,56 5mg90s 1,029 1,0234 2014/TPH/31 44,51 0,09 1,72 973 13 964 19,48 5mg90s 1,029 1,0234 2014/TPH/32 50,76 0,06 0,86 719 7 948 14,92 5mg90s 1,029 1,0234 2014/TPH/33 64,79 0,07 1,09 1 088 12 846 16,05 5mg90s 1,029 1,0234 2014/TPH/34 71,68 0,12 1,87 2 143 24 440 15,68 5mg90s 1,029 1,0234 2014/TPH/35 79,53 0,05 0,74 1 066 10 742 13,68 5mg90s 1,029 1,0234 2014/TPH/36 83,39 0,11 1,65 2 361 25 034 14,6 5mg90s 1,029 1,0234 2014/TPH/37 107,28 0,02 0,28 658 5 520 11,31 5mg90s 1,029 1,0234 2014/TPH/38 96,06 0,03 0,37 783 6 490 11,21 5mg90s 1,029 1,0234 2014/TPH/39 72,97 0,02 0,28 369 3 664 13,26 5mg90s 1,029 1,0234 2014/TPH/40 78,96 0,03 0,36 559 5 211 12,53 5mg90s 1,029 1,0234 2014/TPH/41 53,45 0,02 0,24 280 2 340 11,09 5mg90s 1,029 1,0234 2014/TPH/42 72,79 0,02 0,26 386 3 427 11,87 5mg90s 1,029 1,0234 2014/TPH/43 87,74 0,03 0,3 621 4 740 10,29 5mg90s 1,029 1,0234 2014/TPH/44 105,22 0,02 0,2 596 3 830 8,66 5mg90s 1,029 1,0234 2014/TPH/44 77,85 0,01 0,19 272 2 702 13,19 5mg90s 1,029 1,0234 Blnk 1 0 0 3 16 0 5mg90s 1,029 1,0234 Blnk 2 0 0 2 27 0 5mg90s 1,029 1,0234 Blnk 3 0 0 0 19 0 5mg90s 1,029 1,0234 sulfanilic acid 8,82 7,78 40,56 17 956 66 294 5,21 5mg90s 1 1 sulfanilic acid 10,86 8,09 41,61 22 492 82 279 5,14 5mg90s 1,0237 1,0164 sulfanilic acid 6,84 8,09 41,61 14 031 52 231 5,14 5mg90s 1,0303 1,0112 sulfanilic acid 8,17 7,78 41,21 16 629 62 413 5,3 5mg90s 1 1 sulfanilic acid 11,88 7,29 33,23 22 709 73 126 4,56 5mg90s 1 1 sulfanilic acid 7,7 7,2 38,92 14 481 55 597 5,41 5mg90s 1 1 Blnk 4 0 0 4 4 844 0 5mg90s 1,027 1,0138 Blnk 5 0 0 0 52 0 5mg90s 1,027 1,0138 Blnk 6 0 0 0 21 0 5mg90s 1,027 1,0138 0 0 0 0 0 0 1,027 1,0138
Table 5: Output of the CNS-analyzer, corrected with the factor of deviation for N, C and C/N ratio.
Repeated measures sample22
%N %C %S 0,04 0 0,32 3 0,00 5 0,06 5 0,31 9 0,00 5
Table 6: Sample 22 did not produce a correct duplicate in the CNS-analyzer, therefore two more duplicates are made to check the real value of the sample.
