| | Ec (S/m) | pH | Cl (mg/L) | SO4 (mg/L) | Al (mg/L) | Ca (mg/L) | Fe (mg/L) | K (mg/L) | Mg (mg/L) | Mn (mg/L) | Na (mg/L) | SiO2 (mg/L) | δD (‰) | δ18O (‰) |
|---|
Drone | 4.98 | 1.01 | 4453 | 1834 | 205 | 120 | 93.4 | 16.7 | 28.4 | 1.31 | 37.5 | 160 | − 48.5 | − 3.64 |
U1 | 4.97 | 1.00 | 4438 | 1840 | 205 | 120 | 96.9 | 16.1 | 28.7 | 1.28 | 36.2 | 158 | − 48.6 | − 3.83 |
- Chemical concentrations, pH, electrical conductivity (EC), and stable isotope ratios of hydrogen and oxygen in lake water sampled by drone, and in lake water sampled by hand at site U1 (i.e., the site of regular sampling; e.g., Ohba et al. 2008). The pH and EC were measured using a handheld pH/EC meter (HORIBA, D-74) equipped with a glass electrode (HORIBA, 9615S-10D) for measuring pH and a two-electrode instrument (HORIBA, 3552-10D) for measuring EC. Both pH and EC values are converted to the reference temperature of 25 °C. The concentrations of Cl and SO4 ions were determined with an ion chromatograph (Thermo Scientific, Integrion). The concentrations of cations were measured by a microwave plasma–atomic emission spectrometer (Agilent Technologies, 4210 MP–AES). The δD and δ18O values were determined by cavity ringdown spectroscopy (Picarro, L2120-i). The analytical precisions of the EC, pH, anion concentration, cation concentration, δ18O, and δD values are ± 0.11 S/m, ± 0.02, ± 0.2%, ± 5%, ± 0.7‰, and ± 0.07‰, respectively
