Table 5.

pH and ion concentrations of lake runoff, lake water, pore water, and snow at Mars Oasis.

Sample	pH	${\text{NH}}_4^{+}$	Na+	K+	Ca2+	Mg2+	${\text{HCO}}_3^{-}$	Cl-	${\text{SO}}_4^{2-}$	${\text{NO}}_3^{-}$	O2	DOC
Runoff	7.6	5.61	118	12.8	2,981	784	1,392	32.6	4,082	3.33	13.0	0.35
Lake water (sample 1)	7.3	6.25	101	14.2	1,238	259	1,771	141	956	2.38	12.2	6.53
Lake water (sample 2)	7.4	4.09	129	20.0	1,540	233	1,573	108	1,310	1.80	12.9	2.43
Lake water (sample 3)	7.5	6.14	85.7	16.6	849	115	768	103	781	0.86	12.7	1.15
Lake water (sample 4)	7.7	3.11	36.8	8.37	510	64.0	1,088	26.1	165	5.92	12.6	m.d.
Pore water	7.4	2.91	124	16.2	2,693	449	652	333	2,464	199	7.31	5.59
Snow	5.7	2.03	16.5	12.0	46.1	3.91	m.d.	19.2	46.2	2.38	m.d.	3.64

DOC, dissolved organic carbon; m.d., missing data.

Data are expressed in μ equivalents L^-1 except for dissolved oxygen and DOC (both mg L^-1) and pH. Data are means of 7, 12, 3, and 4 measurements for runoff, lake water, pore water, and snow, respectively. ${\text{PO}}_4^{3-}$ was below detection limits of 1 μ equivalents L⁻¹