https://doi.org/10.5061/dryad.4qrfj6qmz

Description of the data and file structure

This dataset was collected to investigate the seasonal turnover of the fish-derived kairomone 5α-cyprinol sulfate (CPS) in freshwater ecosystems.

To understand the environmental factors regulating CPS persistence and availability, we conducted a series of controlled laboratory experiments, field measurements, and predictive modeling. The experimental efforts included:

1. CPS Degradation Experiments – Investigating microbial breakdown of CPS in lake water.
2. CPS Exudation Experiments – Measuring how fish excrete CPS under different feeding conditions.
3. Seasonal CPS Monitoring – Tracking CPS concentrations in Reeser Meer Nord Erweiterung (RMNE) over a season.
4. Zooplankton Sampling – Assessing seasonal Daphnia abundance
5. Temperature-Dependent Modeling – Simulating CPS dynamics based on fish feeding and microbial degradation rates.

By integrating chemical analyses (UHPLC-MS), ecological monitoring, and mathematical modeling, this study provides insights into how CPS levels fluctuate in response to biotic (fish feeding, microbial activity) and abiotic (temperature) factors.

Data files

This repository contains tabular data files (.csv) and R scripts (.R) used to analyze and visualize the production, degradation, seasonal occurrence, and modeled dynamics of the fish-derived kairomone 5α-cyprinol sulfate (CPS).

DegradationData.csv

This file contains measurements from the CPS degradation experiment in lake water from Fühlinger See (FS) and Reeser Meer Nord Erweiterung (RMNE). Water was incubated either as autoclaved control or non-autoclaved treatment to test microbial degradation of CPS.

Variables:

• Vial Nr. — unique vial/sample identifier
• Sample.Name — sample name assigned during measurement
• CS added [ng] — amount of cholesteryl sulfate internal standard added (ng)
• Injection volumne — injection volume used for UHPLC-MS analysis (µL)
• Treatment — treatment type; autoclaved control or non-autoclaved microbial treatment
• Replicate — biological replicate ID
• Time [h] — incubation time in hours
• day — sampling day of the experiment
• Lake — lake identity (FS or RMNE)
• Month — month of sampling
• Tray Position — instrument tray position
• CPS [PA] — CPS peak area in the mass spectrometer
• CS [PA] — cholesteryl sulfate peak area in the mass spectrometer
• CPS [ng/L] — CPS concentration in ng/L
• CPS [µg/L] — CPS concentration in µg/L
• Outlier — outlier flag (0 = included, 1 = excluded)

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CalibrationDegradationData.csv

Calibration data used to quantify CPS during the degradation experiment.

Variables:

• CS [ng] — cholesteryl sulfate calibration standard amount (ng)
• CS [PA] — measured peak area of the standard

This file was used to generate the calibration relationship for quantification of CPS in the degradation experiment.

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ExudationData.csv

This file contains measurements from the laboratory fish exudation experiment using individual roach (Rutilus rutilus). The experiment tested how CPS exudation depends on food intake, fish size, and time after feeding.

Variables:

• Sample — sample identifier
• Hours after feeding — time elapsed since feeding (h)
• Day — day of the experiment
• Status — internal sample/treatment status label
• week — experimental week
• Foodstatus — feeding treatment label
• Food amount [% of bodyweight] — food offered as percent of fish body weight
• Fish weight [g] — individual fish body mass (g)
• Food amount [g] — food amount given to each fish (g)
• Vial Vol. [µL] — extract vial volume (µL)
• Injection vol. [µL] — injection volume for UHPLC-MS (µL)
• Aquaria Vol [L] — aquarium volume (L)
• Replicate — replicate ID
• Fish size — fish size category (small, big)
• Temp. — experimental temperature
• Outlier — outlier flag (0 = included, 1 = excluded)
• CS [PA] — cholesteryl sulfate peak area
• CPS [PA] — CPS peak area
• Dilution 1: — dilution factor applied before measurement
• FinalCPS [µg/L] — final CPS concentration in the analyzed sample (µg/L)

Note: In the R analysis, outliers flagged as 1 were excluded before model fitting.

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calibrationExudation.csv

Calibration data used for quantification of CPS in the fish exudation experiment.

Variables:

• CS [ng] — cholesteryl sulfate calibration amount (ng)
• CS [PA] — measured peak area
• Replicate — calibration replicate ID

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LakeCPS RMNE.csv

This file contains CPS concentrations measured in surface water from Reeser Meer Nord Erweiterung (RMNE) between March and September 2023.

Variables:

• Vial — vial identifier
• Probe — sampling site/sample label
• Replicate — technical replicate ID
• Date — month/date label of sampling
• Month — numeric month
• CS added [ng] — amount of cholesteryl sulfate added as internal standard (ng)
• Sample vol. [µL] — processed sample volume
• Year — sampling year
• Injection Vol [µL] — injection volume for UHPLC-MS
• Position — tray position in the measurement sequence
• CPS — CPS peak area
• CS — cholesteryl sulfate peak area
• CPS [µg/L] — calculated CPS concentration in µg/L

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RMNE Secci Temp.csv

This file contains environmental data from RMNE corresponding to the seasonal CPS monitoring.

Variables:

• Month — month of sampling
• Temperature [°C] — lake water temperature (°C)
• SecchiDepth [m] — Secchi depth, a measure of water transparency (m)

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DaphniaAbundanceRMNE.csv

This file contains monthly Daphnia abundance data from RMNE for March to September 2023.

Variables:

• Lake — lake identity (RMNE)
• Datum — sampling date
• Replicate — replicate number
• Depth — sampled depth stratum (1=Epilimniom; 2=Hypolimnion)
• Daytime — day (1) /night (2) sampling category
• Abundance — abundance of Daphnia (Ind/L)
• DateID — internal date identifier
• Zooplankton — zooplankton taxon

Note: The analysis script filters this dataset to Zooplankton == "Daphnia" and then sums abundances by month across samples.

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Code files

Fig.1&2 SI Fig.1_DegradationExperiments.R

R script for analyzing and plotting CPS degradation in lake water.

This script:

• log-transforms CPS concentration data
• fits linear models and mixed-effects models
• estimates degradation rate constants (k) and initial concentrations (C0)
• calculates hourly and daily degradation rates and half-life
• generates plots for control and non-autoclaved treatments
• models temperature-dependent degradation using Q10 scaling

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Fig. 4_CPS Exudation.R

R script for analysis of fish CPS exudation.

This script:

• excludes outliers flagged in the data table
• summarizes CPS exudation by food amount, fish size, week, and temperature
• visualizes the relationship between food amount and total CPS exudation
• fits linear models testing the effect of food amount and fish size on CPS exudation

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Fig. 5_ CPS RMNE Secci and Temp Plot.R

R script for generating seasonal field plots for RMNE.

This script:

• calculates mean monthly CPS concentrations from technical replicates
• plots seasonal CPS concentration in RMNE
• plots temperature and Secchi depth on a shared time axis
• links CPS seasonal trends to environmental conditions

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Fig. 6 Daphnia abundance.R

R script for processing and plotting Daphnia abundance data.

This script:

• filters the zooplankton dataset to Daphnia
• converts abundance values to numeric format
• extracts month information from dates
• translates month labels where needed
• sums Daphnia abundance by month
• plots seasonal abundance in RMNE

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FIg. 7_ netCPS_Model.R

R script implementing a temperature-dependent model of CPS turnover.

This script:

• defines monthly water temperature values
• models CPS exudation and microbial degradation using Q10 scaling
• calculates steady-state/net CPS concentration per fish
• visualizes modeled seasonal CPS dynamics

Code/software

All analyses and visualisations were conducted in Microsoft Excel and R (version 4.2.0; R Core Team, 2022) within the RStudio environment (Posit Team, 2023) to explore CPS degradation, exudation dynamics, and model predictions.