Province-wide changes in water clarity and dissolved organic carbon in Ontario, Canada lakes over six decades
Data files
Jul 06, 2026 version files 2.02 MB
-
BsM_ARU_elevation_20240320.csv
88.11 KB
-
commonDataIDs_aruToBsm_20240307.csv
87.61 KB
-
dataForDryadRepo_landscapeDOC_AR_20241122.csv
179.12 KB
-
manuscriptSubmissionScript_20260217.R
55.33 KB
-
ohnWaterbodies_csvWithCoords.csv
978.83 KB
-
Province.zip
267.42 KB
-
README.md
5.20 KB
-
statDatWide_updatedCyc3_20240520.csv
335.30 KB
-
summaryOfLakeVisits_20260308.xlsx
21.34 KB
-
theme_DOC.R
1.08 KB
Abstract
Declining water clarity driven primarily by increases in dissolved organic carbon (DOC; i.e., ‘brownification’) has been broadly reported across the Northern Hemisphere. In Ontario, Canada, increasing lake DOC concentrations have been reported regionally; however, no broad spatial and temporal water clarity trends for Ontario lakes currently exist. Here, we use data from two provincial monitoring programs to analyze historical (1962–1984), contemporary (2008–2023), and long-term (1962–2023) changes in water clarity across 684 Ontario lakes using DOC concentrations and Secchi depth measurements. Our findings suggest that water clarity in Ontario lakes has declined since 1962, with the greatest declines in water clarity occurring in the contemporary time period. Water clarity declines were greatest in oligotrophic lakes, where DOC concentrations were also shown to have increased over time. Our findings highlight the importance of regional, temporal, and trophic contexts when considering the magnitude and direction of water clarity changes in Ontario lakes.
https://doi.org/10.5061/dryad.r7sqv9snh
Description of the data and file structure
The following files can be used to recreate the analyses within the manuscript.
Files and variables
File: dataForDryadRepo_landscapeDOC_AR_20241122.csv
Description: Main dataset for analyses
Variables
- commonID: Matching lakeID for AHI and BsM dataset
- lat: Latitude (decimal degrees)
- long: Longitude (decimal degrees)
- samplingProgram: Provincial Sampling Program (AHI or BsM)
- secchiDepth: Secchi depth (m)
- maxDepth: Lake maximum depth (m)
- yearSample: Sample year
- DOC: dissolved organic carbon (mg/L)
- TDP: total dissolved phosphorus (ug/L)
- scaled_yearSample: centered year sample
- scaled_secchi: centered year sample
- scaled_maxDepth: centered year sample
File: commonDataIDs_aruToBsm_20240307.csv
Description: This file was used to create a commonID between the AHI and BsM datasets
Variables
- BsM_lakeName: Lake name as written in BsM dataset
- latBsM: Latitude (decimal degrees)
- longBsM: Longitude (decimal degrees)
- bsmWaterbodyID: Unique lake ID for waterbody within BsM dataset
- ARU_lakeName: Lake name as written in AHI dataset
- latARU_conv: Latitude (decimal degrees)
- longARU_conv: Longitude (decimal degrees)
- ARU_LID: Unique lake ID for waterbody within AHI dataset
- Notes: comments (text)
- commonID: Matched ID for indicating paired data between BsM and AHI dataasets
File: statDatWide_updatedCyc3_20240520.csv
Description: This is a datasheet that is required for a certain chunk of code
Variables
- BsM_Cycle: Unique Ontario broadscale managment program cycle (1,2,3)
- FMZ: Ontario MNR fishery management zone
- lakeName: Lake name as reported in BsM database
- waterbodyID: Unique lake ID for waterbody within BsM dataset
- secchiDepth: Secchi depth (m)
- surfaceArea: Lake surface area (ha)
- lakeVolume: Lake volume (m3)
- maxDepth: Maximum lake depth (m)
- meanDepth: Mean lake depth (m)
- lat: Latitude (decimal degrees)
- long: Longitude (decimal degrees)
- yearSample: Sample year for observation (yr)
- COLTR (TCU): True Colour (TCU)
- pH: Lake pH (unitless)
- cond: Specific conductivity (us/cm)
- alk: Alkalinity (mg/L)
- Ca: Calcium (mg/L)
- MGUT (mg/L): Magnesium (mg/L)
- Na: Sodium (mg/L)
- KKUT (mg/L): Potassium (mg/L)
- CLIDUR (mg/L): Chloride (mg/L)
- SSO4UR (mg/L): Dissolved sulphate (mg/L)
- SIO3UR (mg/L): Silicates (mg/L)
- FEUT: Total unfiltered iron (mg/L)
- DIC: Dissolved inorganic carbon (mg/L)
- DOC: Dissolved organic carbon (mg/L)
- NNHTUR (mg/L): Total Unfiltered Ammonium + Ammonia (mg/L)
- NNOTUR (ug/L): Total unfiltered nitrate and nitrite (ug/L)
- TKN: Total Kjeldahl Nitrogen (mg/L)
- TDP: Total dissolved phosphorus (mg/L)
- dateSample: Sample date for water chemistry
- NtoPratio: Total N to total P ratio
File: summaryOfLakeVisits_20260308.xlsx
Description: This file describes how many times a lake (i.e., commonID) was visited for between 1962 to 2023
Variables
- commonID: lake name
- Count of commoinID: The amount of times a given lake was sampled between 1962 to 2023 (i.e., inclusive of all AHI and BsM samples
File: Province.zip
Description: Zip folder that includes simple shapefile for outline of Ontario
Variables
- Province.shp: Shapefile file, including all necessary auxiliary files
File: BsM_ARU_elevation_20240320.csv
Description: File including elevation above sea level for all study lakes
Variables
- BsM_lakeName: Unique lake name as described in BsM dataset
- latBsM: BsM lake latitude from BsM (decimal degrees)
- longBsM: BsM lake longitude from BsM (decimal degrees)
- bsmWaterbodyID: unique lakeID from BsM dataset
- ARU_lakeName: Unique lake name as described in AHI dataset
- latARU_conv: lake latitude from AHI (decimal degrees, converted from UTMs)
- longARU_conv: lake longitude from AHI (decimal degrees, converted from UTMs)
- ARU_LID: Unique lakeID as described in AHI dataset
- Notes: Comments
- elevation: Elevation (meters above sea level)
File: ohnWaterbodies_csvWithCoords.csv
Description: Geographic description of lakes associated with BsM data
Variables
- OGF_ID: Unique lakeID for Ontario-wide OHN database
- WATERBODY_TYPE: Waterbody type
- OFFICIAL_NAME_LABEL: Given name for waterbody
- Longitude: Longitude (decimal degrees)
- Latitude: Latitude (decimal degrees)
Code/software
Files: manuscriptSubmissionScript_20260217.R, theme_DOC.R
Description: Analysis and visualization script associated with manuscript. All analyses were conducted using R version 4.4. All packages used are described within the manuscript. To maintain working directory dependency and code functionality, create an R project and within that project create a "data" subfolder in which all necessary data files are saved. Create another subfolder for "scripts", in which "theme_DOC.R" can be saved, which maintains plot formating. All necessary packages are freely available through CRAN
Data were part of two Ontario Ministry of Natural Resourcess datasets -- the Aquatic Habitat Index (1962-1986) and the Broadscale Monitoring Program (2003 to present)