Evidence for intraspecific variation of salinity tolerance in zooplankton collected from lakes of differing salinities on the Great Plains
Data files
Jan 10, 2026 version files 50.26 KB
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Appendix_analysis_code.Rmd
19.19 KB
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chemdata.csv
6.34 KB
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README.md
2.39 KB
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Supplementary_material_raw_data.csv
22.34 KB
Abstract
The Great Plains are expected to become drier over the coming decades as droughts caused by natural variation in precipitation are exacerbated by climate change. The resulting increases in lake salinity may impact biodiversity, including zooplankton. To better understand how salinity changes will affect zooplankton, our study evaluated intraspecific differences in salinity tolerance of zooplankton originating from lakes with differing salinity levels. Three species, including Ceriodaphnia laticaudata, Daphnia magna and Daphnia schodleri were collected from lakes near Saskatoon, Saskatchewan and were subjected to acute salinity tolerance tests. The 24-h and 48-h half-effective concentration (EC50) results for all three species were estimated using three replicate cultures established for each species. Calculations for EC50 values were conducted using the drc library in the R programming language. Comparisons of the EC50 values for individual species among lakes were made using ANOVAs. The EC50 values for all three species were significantly lower for cultures originating from lower salinity lakes, providing evidence that the osmoregulatory capacity of some zooplankton species may change through evolution or acclimation.
Dataset DOI: 10.5061/dryad.j0zpc86vv
Description of the data and file structure
Experiments were conducted with three species of zooplankton collected from lakes near Saskatoon Saskatchewan to estimate salinity tolerance. EC50 values were calculated from the dose-response relationships using the drc package in the R programming environment.
Files and variables
File: Appendix_analysis_code.Rmd
Description: This code reproduces the analysis in the associated publication, including calculating EC50 values and making figures. The code is in R Markdown format and can be opened with RStudio.
File: Supplementary_material_raw_data.csv
Description: This contains the data collected from salinity tolerance experiments used to construct dose response relationships between salinity and survivorship.
Variables
- Lake: Lakes near Saskatoon, Saskatchewan from which zooplankton were collected.
- Species: Zooplankton species used in experiment
- Concentration_gL: Concentration_gL indicates the concentration of the artificial saltwater medium used in each treatment.
- n: the number of individuals tested for each experiment.
- Replicate: Replicate indicates the replicate number for each lake (typically 3 replicate experiments per lake).
- Time_h: Length of the experiment to calculate EC50.
- Mortality: Number of dead individuals at the conclusion of the experiment.
- TDS_mgL: Total dissolved solids in mg/L in the lakes from which zooplankton were collected.
File: chemdata.csv
Description: Water chemistry data from lakes visited near Saskatoon, Saskatchewan from which zooplankton were collected for experiments.
Variables
- Lake: Name of the lake from which zooplankton were collected.
- Year: Year the lakes were visited for water chemistry measurements.
- Ion: Type of ion measured.
- Concentration: Result of ion measurement.
- Lake.short: Shortened version of the "Lake" column.
- Units: Units of measurement for the ions measured.
Code/software
The code has been uploaded in R Markdown format (.Rmd file extension). This can be opened in RStudio.
The workflow used and all packages are specified in the markdown file.