# README

## Name of Dataset: Salinization and the toxic alga Prymnesium parvum parvum suppress freshwater rotifers across experimental scales

## Description

This data package contains data and code supporting the work:
Salinization and the toxic alga Prymnesium parvum parvum suppress freshwater rotifers across experimental scales

The dataset investigates the effects of salinization on two rotifer species, Keratella cochlearis and Lepadella patella, during a mesocosm experiment. Experiments were performed to determine the tolerance of rotifers to salinization as well as the impact of the combined stressors of salinity and toxic P. parvum addition.

## Creators or Authors

Margie Glenna,b*, Elisabeth Vargac, Glce Yalcina, Marisa Schulza,b, Magdalena Pchhackerc,d,e, Stella A. Bergera, Jens C. Nejstgaarda, Robert Ptacnikf,g

aLeibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Plankton and Microbial Ecology, Zur alten Fischerhtte, 2, Stechlin, Germany
bHumboldt-Universitt zu Berlin, Faculty of Life Sciences, Unter den Linden 6, 10099 Berlin, Germany
cFood Hygiene and Technology, Centre for Food Science, Clinical Department for Farm Animals and Food System Transformation, University of Veterinary Medicine, Vienna, Veterinrplatz 1, 1210 Vienna, Austria;
dDepartment of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Whringer Strae 38-40, 1090 Vienna, Austria;
eDoctoral School in Chemistry, Faculty of Chemistry, University of Vienna, Whringer Strae 42, 1090 Vienna, Austria;
fWasserCluster Lunz - Biologische Station, Lunz am See, Austria
gDepartment of Natural Sciences and Environmental Health, University of South?Eastern Norway, B, Norway
## Dataset Context 

The dataset was collected for the purpose of investigating the effects of salinization and toxic P. parvum on rotifers in a natural plankton community. Land-based mesocosms were used to treat a natural lake plankton community to 4 levels of salinity and 2 productivity levels. The abundance of the 2 most prevalent rotifer species was monitored in the mesocosms over 34 days. Additionally, dialysis bags were incubated as microcosms inside the mesocosms with the addition of P. parvum to determine the effect of the combined stressors of salinity and the toxin producing alga P. parvum. Lastly, a short-term well-plate assay was used at the end of the microcosm incubation to assess more specifically the toxicity of P. parvum after incubation with the plankton community. Water from each microcosm was incubated in a well plate with Keratella cochlearis and survival of the rotifers were determined after 24 hours. 

We hypothesized that (1) increasing salinity would reduce rotifer abundance; (2) nutrient enrichment would alter rotifer dynamics by boosting primary consumers; and (3) exposure of rotifers to P. parvum would add to the negative salinity effects on rotifer survival. For full methodological details and interpretation of results, please see the publications Glenn et al., in review and Ptacnik et al., preprint (https://doi.org/10.64898/2026.07.10.737327).

## File Format and Data Structure

Raw data is stored in csv files as follows. 
meso_rotifers.csv  abundance data of rotifers in the mesocosms over 34 days

'prymnesin_detection.csv  detection of prymnesin in samples from the dialysis bags after 2 weeks incubation

rotifers_invasion.csv  abundance of rotifers in the dialysis bags after 2-weeks incubation with or without the addition of P. parvum

well_plate.csv  survival of K. cochlearis in a well plate after 24 h exposure to water from the dialysis bags after 2-weeks incubation.

Variables are described in detail in the accompanying data dictionaries. R code for the statistical analysis of the data is stored in one R script named script_aquacosm.R which includes comments to describe each step performed.   

## Usage Rights 
The data of this work are licensed under: Attribution 4.0 International (CC BY 4.0).

## Contact Information

Margie Glenn
margaret.glenn@igb-berlin.de
margie.r.glenn@gmail.com


