Table 1. Field and lab geochemistry and SIs calculated for major minerals.

	End-member waters		Start of in situ microcosm experiments						End of in situ microcosm experiments
	Comal Springs	Aquarena well	Girl Scout Deep	Girl Scout Shallow	LCRA Deep	LCRA Shallow	Paradise Alley Deep	Paradise Alley Shallow	Girl Scout Deep	Girl Scout Shallow	LCRA Deep	LCRA Shallow	Paradise Alley Deep	Paradise Alley Shallow
Fresh/saline	F	S	F	F	F	F	S	S	F	F	F	F	S	S
Total dissolved solids	421	12 600	367	384	381	462	1686	1005	361	377	375	534	1632	1024
Temp (°C)	23.3	21.7	24.8	26.4	26.2	25.3	25.7	26.3	27.9	26.5	24.2	24.6	26.9	26.3
pH	7.14	6.89	7.38	7.32	7.3	7.41	7.0	7.17	7.42	7.39	7.33	7.4	7.02	7.17
Total sulfide	0	88.0	BDL	BDL	0.9	0.38	7.86	2.01	0.2	1.0	BDL	BDL	2.64	4.68
Dissolved oxygen	5.34	0	BDL	BDL	0.1	0.12	0.11	0.08	1.2	0.93	0.76	0.83	0.84	0.47
Alkalinity	273	430	246	265	264	241	325	265	244	270	263	243	307	271
Cl−	19.1	4601	25.9	19.5	15.8	65	576	273	21.8	19.2	14	65.1	558	283
F−	1.2	45.2	3.2	4.8	3.9	3.7	4	6.4	2.3	3.9	3.5	5.9	5.3	6.9
SO42−	31.9	2830	52.4	54.3	44.8	92.4	621	329	41.9	41.3	41	93.4	612	347
NO3−	10.6	56.5	0.2	0.1	1.9	1.3	0.5	0.3	0	4.3	2.5	2.3	0.4	0
Na+	36	3947	18.1	57.2	57.3	45.2	317	192	52.4	50.2	49.4	82.8	328	193
K+	1.1	37.1	1.8	0.6	1.0	3.7	19.6	10.1	0.9	0.6	1	3.2	19.3	10.1
Mg2+	18.8	1337	32.8	24.1	26.7	38.4	113	68	29	24.7	27.2	39.7	105	68.2
Ca2+	93.3	2515	55	56.4	53.8	60.9	182	108	47.1	55.4	55	61.9	167	108
TOC	20.9	7.37	1.10	1.05	1.30	0.93	NM	1.42	NM	NM	NM	NM	NM	NM
TN	0.6	6.85	0.5	BDL	1.00	5.77	NM	3.86	NM	NM	NM	NM	NM	NM
SIcalcite	0.11	0.83	0.1	0.1	0.06	0.14	0.12	0.08	0.12	0.17	0.07	0.12	0.1	0.08
SIdolomite	−0.15	1.71	0.32	0.19	0.17	0.43	0.37	0.31	0.4	0.36	0.18	0.39	0.36	0.31
SIgypsum	−2.02	0.2	−2.01	−1.99	−2.09	−1.77	−0.82	−1.17	−2.17	−2.11	−2.11	−1.78	−0.85	−1.15

Abbreviations: BDL, below detection limit; F, fresh; NM, not measured; S, saline; SI, saturation index; TN, total nitrogen; TOC, total organic carbon.

The end-member fresh and saline waters are represented by, respectively, Comal Springs and the state well LR-67-01-814B at Aquarena in San Marcos, Texas, USA. The geochemical analyses done for the New Braunfels wells were used to model the saturation state of various minerals before and after the in situ microcosm experiments; water collected at the start of the experiments was done after purging the wells, but water collected at the end of the experiments was from the well casing. Units are in mg l⁻¹ unless stated otherwise.