DOI: 10.5061/dryad.j0zpc86vv
title: Evidence for intraspecific variation of salinity tolerance in zooplankton collected from lakes of differing salinities on the Great Plains

description: 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.
description: # Evidence for intraspecific variation of salinity tolerance in
 zooplankton collected from lakes of differing salinities on the Great
 Plains Dataset DOI:
 [10.5061/dryad.j0zpc86vv](https://doi.org/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.