Mohonk Lake is described in detail in Richardson et al. (2018, 2019). Manual profiles were collected using a thermistor that was lowered through the water column. The thermistor used prior to 25 Oct 1999 was a customized YSI meter with variable resistor that was checked and calibrated every six months using a laboratory microcalibration water bath. A Cole-Palmer thermistor with YSI probe were used between 25 Oct 1999 and 23 August 2002. From 23 August 2002 to 31 December 2017, a Digi-sense 400 series thermistor was used. In 2017, high-frequency (15 min) temperature data were taken using a NexSens T-Node temperature logger downsampled to daily profiles. The downsampled sensor temperatures were highly correlated with the manual temperature profiles, the slope for the regression (0.996 ± 0.005, mean ± SE) was not significantly different than one (t189=0.8, p=0.42). For the days with both sensor and manual profiles, we used the manual profiles. The 19 dates ranged from 09 Mar 2017 and 19 Dec 2017. The temperature profiles and Secchi depths were all taken from the same location, sampling through a hatch in a wharf at the northern end of the lake where depth was 13m. We examined each temperature profile for anomalous values. All extreme and physically unrealistic values (> 40°C or < -5°C) were removed, and all profiles with less than two depths with temperature measurements were removed. To identify physically impossible profiles and data recording or entry errors, we examined each profile for monotonically increasing water densities with a difference below -0.13 kg/m3 to account for temperature measurement resolution from surface to the deepest measurement and removed profiles with either insufficient data or non-monotonically decreasing water densities.
References:
Richardson, D. C., Charifson, D. M., Davis, B. A., Farragher, M. J., Krebs, B. S., Long, E. C., Napoli, M. & Wilcove, B. A. 2018. Watershed management and underlying geology in three lakes control divergent responses to decreasing acid precipitation. Inland Waters, 8(1), 70-81.
Richardson, D. C., Bruno, E. C., Edwards, H. L., Green, D. M., Hollander, A. J., McFadden, S. R., Reid, K. A. & Wander, H. L. 2019. Serial introductions modify a trophic cascade and partially mitigate changes in lake ecosystem structure. Freshwater Science, 38(3), 642-653.
