Data from: Salinization induced under-ice benthic warming, hypoxia, and reduced spring mixing in a rural lake with low road density
Data files
Sep 03, 2026 version files 1.06 MB
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high_frequency_ctd_figures.R
14.81 KB
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in_situ_ctd_depth_profiles.R
5.80 KB
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lake_stability.R
17.65 KB
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muskoka_wind_speed.csv
160.92 KB
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paint_lake_salinity_high_freq_ctd.csv
556.23 KB
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paint_lake_salinity_in_situ_ctd.csv
281.91 KB
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paint_lake_salinity_water_chem.csv
5.71 KB
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README.md
12.49 KB
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water_chem_figures.R
3.41 KB
Abstract
The stratification of ice-covered lakes is currently understood as either cryomictic (mixing near 0 °C) or cryostratified (inverse stratification reaching 4 °C). However, internal or external salt sources may alter these patterns, creating stable stratification with high under-ice bottom water temperatures, a condition we term cryohalostratification, which may lead to anoxia and interference with spring mixing. We measured stratification and water quality over two winters in a rural Canadian Shield lake exposed to a highway. We found high under-ice water temperatures (> 4 °C) and low dissolved oxygen (< 2 mg L-1) because of increases in chloride and sodium. Following a cold winter, stability remained high after ice-off, preventing mixing and prolonging seasonal hypoxia. Lake stability estimates showed that the stability of the lake was enhanced by wind sheltering from the surrounding forest, suggesting that even rural lakes with low road density are susceptible to salinization.
Dataset DOI: 10.5061/dryad.xgxd254z2
Description of the data and file structure
General Study Design
Field surveys were conducted approximately weekly for in situ measurements of ice thickness, water temperature, dissolved oxygen, and specific conductivity during the winters of 2024 and 2025. Two basins in Paint Lake were sampled: the main (western) basin, and the shallow (eastern) outflow basin which is exposed to highway 117 and potential road salt contamination. Water samples were collected weekly below the ice-water interface, and frequently just above the sediments. In situ sampling was conducted while a safe ice cover existed (minimum 10 cm of black ice). Loggers were deployed shortly after ice-on for temperature, dissolved oxygen and conductivity. Temperature loggers were deployed every 0.25-1 m throughout the water column, and dissolved oxygen and conductivity loggers were deployed at the surface and bottom, with an extra DO logger at 4.2 m in 2025. Conductivity loggers were deployed in 2025 only. Loggers were retrieved in late May-mid June.
Methods Description
Ice thickness and quality was measured from an ice core cut from between two auger holes. Water samples were collected using a van Dorn sampler lowered to just below the ice-water interface, and frequently to just below the bottom. If sediments were observed in the water sample, a new hole was cut and the sample retaken. Water samples were filtered through a 50 µm sieve for analysis of TP, NH4, NO2/NO3, DOC, SiO4, Cl, SO4, Ca, Mg, K, & Na; all other variables were unfiltered in the field. In situ depth profiles of water temperature and dissolved oxygen were collected using an RBRmaestro3, which was held just below the water surface for a 30-second calibration period before being slowly lowered to just above the sediment. Specific conductivity profiles were collected using an RBRconcerto using the same method.
Laboratory, field, or other analytical methods
In situ temperature, dissolved oxygen, and conductivity profiles: measurements were recorded every 0.5 seconds. Downcast data was isolated by beginning at 0.5 m depth and ending at the maximum depth recorded. Values were averaged for each 0.1 m depth interval.
High-frequency temperature, dissolved oxygen, and conductivity profiles: measurements were recorded every 10 minutes. Values were averaged over each day.
Water chemistry samples were analyzed at the Dorset Environmental Science Centre laboratory using the following protocols:
Specific conductivity: THE DETERMINATION OF CONDUCTIVITY, pH, AND
ALKALINITY (TOTAL and GRAN) BY POTENTIOMETRY AND COLOUR BY SPECTROPHOTOMETRY IN WATER, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3513.
pH: THE DETERMINATION OF CONDUCTIVITY, pH, AND
ALKALINITY (TOTAL and GRAN) BY POTENTIOMETRY AND COLOUR BY SPECTROPHOTOMETRY IN WATER, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3513.
Dissolved organic carbon: THE DETERMINATION OF MOLYBDATE REACTIVE SILICATES AND DISSOLVED ORGANIC CARBON IN WATER AND PRECIPITATION BY COLOURIMETRY, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, DOCSI-E3422.
Total nitrogen: THE DETERMINATION OF INORGANIC CARBON IN WATER BY ACID SPARGING AND NDIR DETECTION AND TOTAL NITROGEN BY OXIDATIVE PYROLYSIS AND CHEMILUMINESCENCE, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3028.
Dissolved inorganic carbon: THE DETERMINATION OF INORGANIC CARBON IN WATER BY ACID SPARGING AND NDIR DETECTION AND TOTAL NITROGEN BY OXIDATIVE PYROLYSIS AND CHEMILUMINESCENCE, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3028.
Chloride: THE DETERMINATION OF CHLORIDE AND SULPHATE IN SURFACE WATER AND WET DEPOSITION SAMPLES BY AUTOMATED ION CHROMATOGRAPHY (IC), Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, DOIC-E3147.
Sulphate: THE DETERMINATION OF CHLORIDE AND SULPHATE IN SURFACE WATER AND WET DEPOSITION SAMPLES BY AUTOMATED ION CHROMATOGRAPHY (IC), Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, DOIC-E3147.
Sodium: Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3249.
Ammonia/ammonium: THE DETERMINATION OF AMMONIA NITROGEN AND NITRATE PLUS NITRITE NITROGEN IN WATER AND PRECIPITATION BY COLOURIMETRY, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3374.
Potassium: Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3249.
Calcium: Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3249.
Magnesium: Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3249.
Silica: THE DETERMINATION OF MOLYBDATE REACTIVE SILICATES AND DISSOLVED ORGANIC CARBON IN WATER AND PRECIPITATION BY COLOURIMETRY, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, DOCSI-E3422.
Total kjeldahl nitrogen: THE DETERMINATION OF TOTAL KJELDAHL NITROGEN IN SURFACE WATER AND PRECIPITATION BY
CALCULATION, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3424.
True colour: THE DETERMINATION OF CONDUCTIVITY, pH, AND
ALKALINITY (TOTAL and GRAN) BY POTENTIOMETRY AND COLOUR BY SPECTROPHOTOMETRY IN WATER, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3513.
Nitrite/nitrate: THE DETERMINATION OF AMMONIA NITROGEN AND NITRATE PLUS NITRITE NITROGEN IN WATER AND
PRECIPITATION BY COLOURIMETRY, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, E3374.
Dissolved phosphorus: THE DETERMINATION OF TOTAL PHOSPHORUS IN WATER BY COLOURIMETRY, Ministry of the Environment, Conservation, and Parks, Laboratory Services Branch, DOP-E3036.
Files and variables
File: Scott_et_al_2026_Metadata-LO-Letters-data-v3.rtf
Description: Metadata information on Limnology & Oceanography Letters journal template
File: muskoka_wind_speed.csv
Description: Wind speed data from Environment & Climate Change Canada weather station at Muskoka airport (Climate ID 6115529, 44.97° N, -79.30° W)
Variables
- time: Time of observation at 1-hour intervals (yyyy-mm-dd-hh-mm-ss EST)
- wind_spd_km_h: Hourly average wind speed (Metres per second (m s-1))
- wind_spd_roll_avg: Rolling average of hourly wind speeds over previous 12 hours (Metres per second (m s-1))
File: paint_lake_salinity_high_freq_ctd.csv
Description: Temperature, dissolved oxygen, and specific conductivity measurements taken at various depths in the eastern and western basin of Paint Lake during winters 2024 and 2025. See Supplement Table S2 for specifications of individual loggers. Values are reported as daily averages.
Variables
- time: Collection date (yyyy-mm-dd)
- site: The basin of Paint Lake from which measurements were collected
- depth: Depth of logger installation (m)
- temperature: water temperature (Degrees Celsius (°C))
- dissolved_o2_concentration: dissolved oxygen concentration (Milligrams per litre (mg l-1))
- spec_cond: specific conductivity (Microsiemens per centimetre (µS cm-1))
File: paint_lake_salinity_water_chem.csv
Description: Results of chemical analysis of water samples from the eastern and western basins of Paint Lake in the winters of 2024 and 2025, collected under the ice-water interface (1 m) and above the bottom (depth recorded).
Variables
- collection_site: The basin of Paint Lake from which measurements were collected.
- collect_date: Collection date (yyyy-mm-dd)
- depth: Depth of water sample collection (m)
- bicarbonate: Bicarbonate; calculated as (61.0168/12.011)*dic (Milligrams per litre (mg l-1))
- ca: Calcium (Milligrams per litre (mg l-1))
- cl: Chloride (Milligrams per litre (mg l-1))
- con: Specific conductivity (Microsiemens per centimetre (µS cm-1))
- dic: Dissolved inorganic carbon (Milligrams per litre (mg l-1))
- doc: Dissolved organic carbon (Milligrams per litre (mg l-1))
- k: Potassium (Milligrams per litre (mg l-1))
- mg: Magnesium (Milligrams per litre (mg l-1))
- na: Sodium (Milligrams per litre (mg l-1))
- nh3.nh4: Ammonia/ammonium (Milligrams per litre (mg l-1))
- no2.no3: Nitrite/nitrate (Milligrams per litre (mg l-1))
- ph: pH
- si: Silica (Milligrams per litre (mg l-1))
- so4: Sulphate (Milligrams per litre (mg l-1))
- tc: True colour (true colour units (TCU))
- tds: Total dissolved solids (Milligrams per litre (mg l-1))
- tkn: Total kjeldahl nitrogen (Milligrams per litre (mg l-1))
- tn: Total nitrogen (Milligrams per litre (mg l-1))
- tp.f: Total phosphorus (Micrograms per litre (µg l-1))
File: paint_lake_salinity_in_situ_ctd.csv
Description: Temperature, dissolved oxygen, and specific conductivity profiles of Paint Lake East and West basins. All data except specific conductivity collected using an RBRmaestro3, and specific conductivity was collected using an RBRconcerto. Soak periods and upcast data have been removed, and all data has been averaged to 0.1 m depth intervals.
Variables
- site: The basin of Paint Lake from which measurements were collected
- full_date: Collection date (yyyy-mm-dd)
- d_int: Depth interval for which the data was averaged (m)
- temp: Water temperature (Degrees Celsius (°C))
- chl_a: Chlorophyll a (Micrograms per litre (µg l-1))
- do_mgl: Dissolved oxygen (Milligrams per litre (mg l-1))
- do_sat: Dissolved oxygen (% saturation)
- par: Photosynthetically active radiation (Micromoles per square metre per second (µmol m-2 s-1))
- pressure: Water pressure (Decibars (dbar))
- con: Specific conductivity (Microsiemens per centimetre (µS cm-1))
File: high_frequency_ctd_figures.R
Description: Code to plot temperature heat maps, temperature differentials, dissolved oxygen profiles, and conductivity profiles (Figure 3).
File: in_situ_ctd_depth_profiles.R
Description: Code to generate depth profiles from in situ data (Figure 2).
File: water_chem_figures.R
Description: Code to generate a comparison of major ion concentrations (Figure 4) and linear regressions of specific conductivity versus total dissolved solids and chloride, respectively.
File: lake_stability.R
Description: Code to calculate water density, lake number, and critical wind speed; plots 1) the relationship between temperature, salinity, and density, 2) the difference between critical and actual wind speeds, 3) lake number over time (Figure 5).
Code/software
R version 4.4.1 (2024-06-14 ucrt) -- "Race for Your Life"
Copyright (C) 2024 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64
All required packages load at the beginning of each code file.
Each code file should run on its own without loading prior code files. Output is the data figures.
in_situ_ctd_depth_profiles.r Code to generate depth profiles from in situ data (Figure 2).
water_chem_figures.r Code to generate comparison of major ion concentrations (Figure 4) and linear regressions of specific conductivity versus total dissolved solids and chloride, respectively.
high_frequency_ctd_figures.r Code to plot temperature heat maps, temperature differentials, dissolved oxygen profiles, and conductivity profiles (Figure 3).
lake_stability.r Code to calculate water density, lake number, and critical wind speed; plots 1) the relationship between temperature, salinity, and density, 2) difference between critical and actual wind speeds, 3) lake number over time (Figure 5).
Access information
Other publicly accessible locations of the data:
- Scott, R.W., J. Culpepper, R.H.S. Hutchins, J.A. Rusak, M.G. Wells, and S. Sharma. 2026. Data from: “Minimal road salt inputs can prevent spring overturn in small, forested lakes.” Figshare [dataset]. https://doi.org/10.6084/m9.figshare.31719091.
Data was derived from the following sources:
- Wind speed data from Environment & Climate Change Canada weather station at Muskoka Airport (Climate ID 6115529, 44.97° N, -79.30° W)