Nutrients were added to Peter and Tuesday lakes to cause algal blooms. Details on
nutrient additions (start/end dates, loading rates, N:P ratios) are described in
Wilkinson et al. 2018. (Ecological Monographs 88:188-203). Methods are described in Pace
et al. 2021 (Limnology and Oceanography ADD ISSUE + PAGE NUMBER), Wilkinson et al. 2018
(Ecological Monographs 88:188-203), and Pace et al. 2017 (Proceedings of the National
Academy of Sciences USA 114: 352-357). These publications including supplements should
be consulted for details.
For chlorophyll-a concentrations, surface water samples (0.5m depth) were collected
daily at the center of each lake. Water samples were returned to the lab and filtered.
Filters were immediately frozen and later extracted for fluorometric measurements of
chlorophyll a following the methods described in the publications above.
Phycocyanin, water temperature, and fluorescent dissolved organic matter (FDOM) were
measured every 5 minutes by automated sensors deployed at a depth of 0.75m from a raft
at the center of each lake. Phycocyanin and temperature were measured using Hydrolab
DS5X data sondes and FDOM was measured by WET Labs ECO fluorometers. Sensors were
calibrated monthly according to manufacturer recommendations; for phycocyanin and FDOM,
manufacturer-provided calibration curves were used and so measurements should be
interpreted as relative and not corresponding to exact, physical units. High frequency
data were averaged to daily measurements. See Pace et al. 2021 (Limnology and
Oceanography ADD ISSUE + PAGE NUMBER) for details on how missing data gaps were
filled.
Nighttime respiration estimates were obtained from high frequency measurements of
dissolved oxygen between the hours of 22:00 and 04:00 using the bookkeeping method with
correction for atmospheric gas exchange. See Pace et al. 2021 (Limnology and
Oceanography ADD ISSUE + PAGE NUMBER) for details and how missing data gaps were
filled.
