- File "readme.txt". It's this file. It contains explanation of the other files present in this dataset, the variables and their units. 

- File "FTIR.csv": the second to sixteenth columns correspond to different samples of biomass from the hyperaccumulator Bornmuellera emarginata, collected at different times (0, 4, 8 and 12 weeks). The data in each column is the absorbance of the sample at different wavenumbers (WN). The wavenumbers (expressed in cm-1) are indicated in the first column (WN).
 
- File "biomass.csv". This file contains the following columns:
	BOX_CODE: is the code used to name each of the experimental units. There were 16, but all the earthworms died in one box (number 11), so this box was not considered in the analyses. 
	Time: the time since the beginning of the experiment when the samples were collected, expressed in weeks.
	B_DW: dry weight of the Bornmuellera emarginata biomass, expressed in grams.
	VC_DW: dry weight of the vermicompost used as bedding for the earthworms, expressed in grams.
	EW_N: number of individuals of the earthworm species Eisenia andrei collected from each experimental unit.
	EW_tFW: total fresh weight of all the earthworms collected in each experimental unit, expressed in grams.
	
- File "nickel.csv". This file contains the following columns:
	BOX_CODE: is the code used to name each of the experimental units. There were 16, but all the earthworms died in one box (number 11), so this box was not considered in the analyses. 
	Time: the time since the beginning of the experiment when the samples were collected, expressed in weeks.
	B_DW: dry weight of the Bornmuellera emarginata biomass, expressed in grams.
	VC_DW: dry weight of the vermicompost used as bedding for the earthworms, expressed in grams.
	EW_tDW: total dry weight of all the Eisenia andrei individuals collected in each experimental unit, expressed in grams.
	CAST_DW: total dry weight of the earthworms' casts, expressed in grams. 
	B_NiT: pseudototal Nickel concentration in the hyperaccumulator biomass, expressed in mg kg-1.
	B_Ni_DTPA: DTPA-extractable Nickel concentration in the hyperaccumulator biomass, expressed in mg kg-1.
	VC_NiT: pseudototal Nickel concentration in the vermicompost bedding, expressed in mg kg-1.
	VC_Ni_DTPA: DTPA-extractable Nickel concentration in the vermicompost bedding, expressed in mg kg-1.
	EW_NiT: pseudototal Nickel concentration in the earthworm tissues, expressed in mg kg-1.
	CAST_NiT: pseudototal Nickel concentration in the earthworms' casts, expressed in mg kg-1.
	B_Ni_mg: total amount of Nickel in the hyperaccumulator biomass, expressed in mg.
	VC_Ni_mg: total amount of Nickel in the vermicompost bedding, expressed in mg.
	EW_Ni_mg: total amount of Nickel in the earthworm tissues, expressed in mg.
	CAST_Ni_mg: total amount of Nickel in the earthworms' casts, expressed in mg.

- File "composition.csv". This file contains the following columns:
	BOX_CODE: is the code used to name each of the experimental units. There were 16, but all the earthworms died in one box (number 11), so this box was not considered in the analyses. 
	Type: is the type of sample analysed. It can be B (hyperaccumulator biomass) or VC (vermicompost bedding).
	Time: the time since the beginning of the experiment when the samples were collected, expressed in weeks.
	pH: is the pH of the sample, measured in water with a ratio 1:10 (w:v).
	EC: is the electrical conductivity of the sample, expressed in mS cm-1.
	Bas_Resp: is the basal respiration of the sample, expressed in µg CO2 g-1 DW h-1.
	C: is the total carbon concentration in the sample, expressed in % of mass. 
	N: is the total nitrogen concentration in the sample, expressed in % of mass.
	Al: is the pseudototal aluminum concentration in the sample, expressed in mg kg-1.
	Ca: is the pseudototal calcium concentration in the sample, expressed in mg kg-1.
	Co: is the pseudototal cobalt concentration in the sample, expressed in mg kg-1.
	Cr: is the pseudototal chromium concentration in the sample, expressed in mg kg-1.
	Cu: is the pseudototal copper concentration in the sample, expressed in mg kg-1.
	Fe: is the pseudototal iron concentration in the sample, expressed in mg kg-1.
	K: is the pseudototal potassium concentration in the sample, expressed in mg kg-1.
	Mg: is the pseudototal magnesium concentration in the sample, expressed in mg kg-1.
	Mn: is the pseudototal manganese concentration in the sample, expressed in mg kg-1.
	Na: is the pseudototal sodium concentration in the sample, expressed in mg kg-1.
	Ni: is the pseudototal nickel concentration in the sample, expressed in mg kg-1.
	P: is the pseudototal phosphorus concentration in the sample, expressed in mg kg-1.
	S: is the pseudototal sulphur concentration in the sample, expressed in mg kg-1.
	Zn: is the pseudototal zinc concentration in the sample, expressed in mg kg-1.