Table 2A.

Physical and chemical properties of hot spring water samples^a.

Parameter	Eiland	Mphephu	Sagole	Siloam	Souting	Tshipise
Latitude (S)	23°39′31″	22°54′20″	22°31′45.4″	22°53′22.6″	23°25′9 ″	22°36′31.5″
Longitude (E)	30°40′23.6″	30°10′38″	30°40′50″	30°11′39″	30°54′44″	30°10′16.7″
Elevation (masl.)	433	796	446	841	389	542
Temperature (°C)	40–42	43	45	63–67	40.1–43.9	58
Estimated depth (m)b	700–1050	767–1150	830–1250	1500–2250	730–1100	1267–1900
pH	7.63	8.08–8.19	9.24–9.70	8.8–9.5	7.8	8.3–8.94
TDS (ppm)	>1862	275	237	252	10130	523
O2 (M)	n.a.	1.3 × 10−4	1.9 × 10−5	6.9 × 10−5	n.a.	6.1 × 10−5
Na+ (M)	2.7 × 10−2	1.9 × 10−3	2.8 × 10−3	2.9 × 10−3	1.5 × 10−1	6.8 × 10−3
K+ (M)	5.6 × 10−4	2.9 × 10−5	2.8 × 10−5	7.2 × 10−5	7.9 × 10−4	1.1 × 10−4
Ca2+ (M)	1.3 × 10−3	3.4 × 10−4	3.3 × 10−5	3.4 × 10−5	6.0 × 10−3	1.4 × 10−4
Mg2+ (M)	3.9 × 10−4	4.6 × 10−4	2.9 × 10−6	5.5 × 10−4	3.3 × 10−3	6.7 × 10−6
NO−3 (M)	4.0 × 10−5	3.4 × 10−5	<d.l.	<d.l.	4.3 × 10−5	9.8 × 10−6
Cl− (M)	2.8 × 10−2	1.1 × 10−3	1.4 × 10−3	1.3 × 10−3	1.6 × 10−1	4.8 × 10−3
SO2−4 (M)	1.5 × 10−3	9.5 × 10−5	1.9 × 10−4	1.1 × 10−5	7.9 × 10−3	5.5 × 10−4
HPO2−4 (M)	2.6 × 10−4	<d.l.	<d.l.	<d.l.	<2.5 × 10−5	2.8 × 10−5
DIC (M)	<d.l.	2.5 × 10−3	2.0 × 10−3	2.0 × 10−3	n.a.	2.2 × 10−3

^aThis table is adapted from Olivier et al. (2011). Adaptions include the conversion of the various geochemical quantities of Mphephu, Sagole, Siloam, and Tshipise into molar concentrations and the addition of Eiland and Souting into the dataset.

^bEstimated depth = (temperature − mean annual surface temperature)/geothermal gradient, where the mean annual surface temperature was assumed to equal 20 °C and the geothermal gradient was assumed to be 20 °C km⁻¹ and 30 °C km⁻¹.

masl., meters above sea level; n.a., data not available; <d.l., below detection limit.