Fig. 2: Time-series concentration for a few representative solutes.
a Dissolved Organic Carbon (DOC). b Dissolved Inorganic Carbon (DIC). c Fe. d Al. e Pb. f Total nitrogen (TN). g Mg. h Ca. i Cd. j SO4. Stream concentration (left Y axis) and discharge (blue lines, right Y axis) for a few representative solutes that have seen concentration changes in recent years (left), and those still remained relatively similar year-to-year patterns in 2016–2019 (right). Note that the X axis (time) is shrunk for the 2000–2015 long-term data (black+, monthly or every other month, sampled USGS water quality site at the watershed outlet) to enable clear visualization of the short-term high-frequency data (red open square, this work, at Coal-11, sampled every other day at about 2/3 creek length toward the outlet) in 2016–2019. Time series for other solutes are in Supplementary Figs. 2 and 3.
