Data publication: Elemental data from transpired fluid from Norway spruce needles of the Horizon 2020 project NEXT

<strong>1. Overview</strong>

This repository contains the **final, cleaned chemistry data** that were produced from the 2019 Raja field campaign of the Horizon 2020 Project NEXT.<br>
The data combine:

Norway spruce needle transpired fluids concentrations for a set of selected elements.
Corresponding soil‑till depth, point location, lithology and basic tree information.
Element‑specific relative‑standard‑deviation (RSD) uncertainties that were calculated from laboratory‑derived uncertainty parameters.

All files are provided in **CSV** format (UTF‑8, `,` separator) and/or the R programming language binary format RData.

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<strong>2. Column description</strong>

**Field Descriptions for Repository Metadata**

#### **Point Identification &amp; Metadata**<br>
1. **PointID** – Unique identifier for each sampling point in the dataset (e.g., `NEXT-2019-193`).<br>
2. **till_depth** – Depth of the till layer (in meters) at the sampling location.<br>
3. **ID_num** – Numeric identifier for the point (e.g., `193`).<br>
4. **grainsize_2mm_pct** – Percentage of grain size &gt;2mm in the soil sample (proxy for rock fragments or coarse material).<br>
5. **OM_thickness** – Thickness of organic matter (cm) in the soil profile.<br>
6. **Soilwetness_by_photo** – Soil wetness category inferred from field photos (e.g., `mesic` = moist, `sub-xeric` = moderately dry).<br>
7. **Soilwetness_cat** – Numeric ranking of soil wetness (likely 1–7, with `1` = driest, `7` = wettest).<br>
8. **notes_by_photos** – Qualitative observations from site photos (e.g., "paludified areas nearby," "boulders present").

#### **Geophysical &amp; Electrical Properties**<br>
9. **conductivity_ph-acid** – Electrical conductivity (EC) measured after acidification (mS/m).<br>
10. **conductivity_ph-initial** – Initial EC of the soil sample (mS/m).<br>
11. **conductivity_pit** – EC measured in the field pit (mS/m).<br>
12. **conductivity** – Conductivity averaged or processed for analysis (units vary).<br>
13. **dielectric permittivity_pit** – Dielectric constant measured in the pit (proxy for soil moisture).<br>
14. **dielectric permittivity** – Processed or averaged dielectric permittivity value.<br>
15. **pH_initial** – Initial pH of the soil sample.<br>
16. **pH_with acid** – pH after acidification (indicates buffer capacity).<br>
17. **pore water conductivity** – EC of extracted pore water (mS/m).

#### **Geospatial &amp; Environmental Context**<br>
18. **VTEM, TMI, APR** – Geophysical survey metrics (VTEM = Vertical Electromagnetic, TMI = Total Magnetic Intensity, APR = Airborne Radiometrics).<br>
19. **Soilwetness** – Categorical soil wetness classification (e.g., `mesic`, `sub-xeric`).<br>
20. **Soiltype** – Predominant soil type (e.g., `mineral soil`, `peat`).<br>
21. **Naturetype** – Ecological classification (e.g., `Boreaaliset luonnonmetsät` = "Boreal natural forests").<br>
22. **TMI_class** – Categorization of Total Magnetic Intensity (e.g., `low`, `middle`, `high`).<br>
23. **Lithology** – Original rock type classification (e.g., `Calcsilicate rocks`, `Mafic rocks`).<br>
24. **Lithology_updated** – Updated lithological classification (refining earlier interpretations).<br>
25. **Lithology_updated_Sol** – Lithology-specific to soil horizons (e.g., `Mafic rocks + quartzite`).<br>
26. **Mineralization** – Qualitative assessment of mineralized zones (e.g., `barren`, `potential`, `min`).<br>
27. **Deposit** – Type of geological deposit (e.g., `Till`, `hardpan layer`).<br>
28. **TMI_cat, VTEM_cat, APPRES_cat** – Categorized geophysical survey results (e.g., `high` intensity).<br>
29. **vegetation_class_EFTAS** – Vegetation classification (e.g., `mesic heath forest`).<br>
30. **i.ID_num** – Redundant numeric ID (same as `ID_num`).<br>
31. **x, y** – Cartesian coordinates for the sampling point.<br>
32. **Fotos** – Reference to associated field photos (e.g., `104-0905`).

#### **Site &amp; Sampling Details**<br>
33. **GeneralSiteDescription** – Textual description of terrain (e.g., "flat, paludified area starts 1m below").<br>
34. **ForestType** – Dominant forest type (e.g., `VMT` = "Välimetsä" [forest type code]).<br>
35. **Soil_paludification** – Degree of peatland/wetland influence on soil (e.g., `not paludified`).<br>
36. **Soil_nutrient_status** – Nutrient availability assessment (e.g., `normal`).<br>
37. **Observations2019** – Anomalies or notes from 2019 fieldwork (e.g., "eggs of gnomes in upper podsol layer").<br>
38. **SedimentType** – Type of sediment observed (e.g., `Till`, `Sand`).<br>
39. **SedimentGenesis** – Origin of sediment (e.g., `glacial`, `alluvial`).<br>
40. **Pointtype** – Classification of sampling point (e.g., `replicate`).<br>
41. **TMI_intensity, VTEM_intensity, APPRES_intensity** – Quantitative geophysical survey intensities.<br>
42. **GPS-Easting, GPS-Northing** – Precise GPS coordinates for the point.<br>
43. **SampleID** – Unique identifier for lab samples (e.g., `TF-NEXT-2019-193-NrS-tf-0A`).<br>
44. **Date_full** – Timestamp of sample collection/analysis.

#### **Geochemical Data**<br>
45. **Al, B, Ba, Bi, ... Zn** – Concentrations of elements (likely in **ppm/mg/g**) measured via lab analysis (e.g., ICP-MS).<br>
   *Note: These columns represent a full suite of geochemical elements (e.g., Aluminum, Barium, Lead, Zinc) critical for mineral exploration, environmental studies, or soil health assessments.*

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### **Key Notes for Repository Users**<br>
- **Units**: Conductivity (mS/m), pH (unitless), dielectric permittivity (dimensionless), GPS coordinates (meters, local system).<br>
- **Categorical Fields**: Wetness, lithology, and mineralization use standardized codes (e.g., `mesic` vs. `xeric`).<br>
- **Geophysical Data**: VTEM/TMI/APR are airborne survey metrics linked to subsurface mineralization.<br>
- **Geochemical Data**: Elemental concentrations are essential for understanding soil fertility, contamination, or ore potential.

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### **Suggested Use Cases**<br>
- **Mineral Exploration**: Cross-reference `Mineralization` + `TMI_cat` with elemental data (e.g., high `Fe`, `Cr` for mafic rocks).<br>
- **Soil Science**: Analyze `Soilwetness` vs. `dielectric permittivity` to model moisture regimes.<br>
- **Ecological Studies**: Correlate `vegetation_class_EFTAS` with `Soil_nutrient_status`.