Supplementary Table 2 Summary of the 19 environmental variables measured from the lakes in the diatom surface sediment training set, indicating units of measurement, summary statistics (average, minimum, maximum and median), data transformations (trans.) applied prior to numerical analyses (e.g. log or square root) and the abbreviated code
Type / Variable / Unit / Average / Max. / Min / Median / Trans. / Code
Major ion chemistry / Conductivity / μS cm-1 / 9456 / 138100 / 55 / 464 / Log(x) / Lg_COND
pH / 9.81 / 10.62 / 7.09 / 8.75 / None / pH
Sodium / mg l-1 / 2301 / 40719.81 / 1.3 / 12.5 / Log(x) / Lg_Na
Potassium / mg l-1 / 650 / 15473.95 / 2.9 / 14.9 / Log(x) / Lg_K
Calcium / mg l-1 / 22 / 61.6 / 3 / 20.18 / Log(x) / Lg_Ca
Magnesium / mg l-1 / 28.96 / 134 / 1.96 / 24.18 / Log(x) / Lg_Mg
Fluoride / mg l-1 / 2.91 / 40.39 / 0.04 / 0.78 / Log(x) / Lg_F
Chloride / mg l-1 / 979 / 37991.89 / 1.15 / 3.88 / Log(x) / Lg_Cl
Strontium / mg l-1 / 1.18 / 6.56 / 0.06 / 0.52 / Log(x) / Lg_Sr
Barium / mg l-1 / 0.39 / 5.85 / 0.004 / 0.08 / Log(x) / Lg_Ba
Total S / mg l-1 / 276.85 / 12380 / 0.091 / 2.31 / Log(x) / Lg_Stot
Silica / mg l-1 / 13.25 / 36.76 / 0.11 / 12.58 / None / Si
Nutrient / Total P / μg l-1 / 406.25 / 13720 / 1.68 / 24.61 / Log(x) / Lg_TP
Total N / μg l-1 / 877.69 / 11914 / 66.22 / 417.2 / Log(x) / Lg_TN
Physical / Altitude / m.a.s.l / 1186 / 1568 / 903 / 1176 / Square root / SQ_ALT
Max. depth / m / 32.05 / 141 / 0.01 / 19.8 / Square root / SQ_DEPTH
Secchi depth / cm / 154.87 / 770 / 0.02 / 115 / None / SECCHI
Temperature / °C / 25.82 / 32.3 / 18.71 / 25.82 / None / TEMP_S
DIC / mg l-1 / 497 / 12221.68 / 4.89 / 47.5 / Log(x) / Lg_DIC
TOC / mg l-1 / 38.92 / 668.87 / 0.56 / 5.48 / Log(x) / Lg_TOC
Catchment impact / Dummy1* / n/a / n/a / n/a / n/a / None / NONE / SEMI / FULL
Lake status / Dummy2* / n/a / n/a / n/a / n/a / None / OPEN / SEASON / CLOSE

* Dummy variable – is used to denote the presence or absence of the variable using 0 or 1 codes.

1 Catchment impact (based on contemporary lake setting): whether the lake catchment was subject to human activity. NONE (protected in forest reserves and national parks), SEMI (signs of human activity, e.g. clearance) and FULL (over 50% of the catchment impacted). Status assigned according to field observations and map data.

2 Lake status: whether the lake system is OPEN (permanent inflow and outflow), SEASON (outflow following seasonal rains) or closed (CLOSE; no dry season outflow).