Temporal and spatial variability of terrestrial diatoms at the catchment scale: 
controls on productivity and relation to other soil algae

This data is linked to: Foets, Jasper (2020), “Temporal and spatial variability of terrestrial diatoms
at the catchment scale”, Mendeley Data, v1, http://dx.doi.org/10.17632/9s28gvnr53.1

Sampling dates
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05/12/2017
09/01/2018
20/02/2018
19/03/2018
18/04/2018
15/05/2018
12/06/2018
17/07/2018
16/08/2018
18/09/2018
09/10/2018
21/11/2018


Explanation of the numbers in the dataset for habitat type, shading, disturbance and soil type
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Habitat type
- 1 = Agricultural field
- 2 = Grazed grassland
- 3 = Agricultural grassland
- 4 = Undisturbed grassland
- 5 = Forest

Shading
- 1 = no
- 2 = partly
- 3 = yes

Disturbance
- 1 = no
- 2 = yes

Soil type
- 1 = Sandstone
- 2 = Marls
- 3 = Schists
- 4 = Luxembourg red sandstone
- 5 = Alluvial

Remarks on meteorological data
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All data has been retrieved from https://www.am.rlp.de/Internet/AM/inetcntrLUX.nsf/cuhome.xsp?src=L941ES4AB8&p1=K1M7X321X6&p3=343GO6H65M

The data shown,is the Average of seven days prior to the sampling day.

Air temperature 5 cm above the soil surface, measured at the weather station in Useldange (280m), was used.

The air temperature was then adapted according to the altitude and the habitat type.
- We used the general equation: -0.65°C*100m (Altitude) for that.
- Also, an additional 2°C were deducted for forested sites.

Calculation storage deficit (SD):
water balance (WB) = previous WB + precipitation - discharge - evpotranspiration with WB(0) = 50 mm
SD = previous SD - WB with SD(0) = 440 mm

Calculation potential evapotransration (Epot_PM) following FAO Penman-Monteith:
Gr  #global radiation in W m-2
Rn <- 0.70 * Gr * 0.0036   #net radiation in MJ m-2 d-1
RH  #Relative humidity
G <- 0  #soil heat flux. Assumption
Ta # Mean daily air temperature
Delta <- 4098 * ( 0.6108 * exp((12.27 * Ta) / (Ta + 237.3))) / ((Ta + 237.3)^2)  #slope vapour pressure curve
upsilon <- 0.065  #psychrometric constant, value taken for 300 m asl
e_s <- 0.61078 * exp(17.27 * Ta / (237.3 + Ta))  #saturation vapour pressure
e_a <- RH / 100 * e_s   #actual vapour pressure
u  #average wind speed at 2m
Epot_PM <- ( 0.408 * Delta * (Rn - G) + upsilon * 900 / (Ta + 273) * u * (e_s - e_a) ) / ( Delta + upsilon * (1 + 0.34 * u ) )


Remarks on physico-chemical data
--------------------------------
TN = Total Nitrogen
DOC = Dissolved organic carbon

Remarks on pigment analysis
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Wet weight = weight of the sample after centrifugation and removal supernatants 
Dry weight = weight of the sample after freeze-drying

Remarks on Biovolume calculations
---------------------------------
Diatom size estimations were collected from OMNIDIA, 
after we used the excel file provided by Rimet and Bouchez (2012). If two datasets gave a different result, 
we checked the sizes of the species and took the value that was most related to our measurements
The missing volumes were calculated (valve thickness was derived from Rimet and Bouchez (2012))
or the same biovolume was used for morphologically similar species.