Long-term monitoring reveals biomass loss and concurrent dominance changes in coastal zooplankton community
Data files
Feb 10, 2026 version files 205.51 KB
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final_new_revisions_script.R
72.89 KB
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README.md
5.58 KB
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storfjarden_time_series.csv
127.04 KB
Abstract
Time series dataset from Tvärminne Storfjärden. Data includes Zooplankton biomass, physical and chemical parameters collected between 1993 and 2021.
All information about taxa is biomass in mg/m³. Biomass was calculated from standard values considering the species (if available) and sex of each individual (HELCOM monitoring guidelines, Hernroth 1985).
Dataset DOI: 10.5061/dryad.08kprr5h3
Description of the data and file structure
Zooplankton samples were generally collected once a month throughout the year, including the winter season. Samples (vertical net tows) were taken during the day using a 150 μm Hensen hand-net with a 0.35 m diameter from a depth of 25 m to the surface (depth of the sampling site is approx. 32 m). If the sea surface was frozen, a hole was drilled or cut into the ice. The samples were stored in 4% buffered formalin and analysed microscopically. Prior to the analysis, the samples were divided using a Folsom splitter (max 10 times which equals a 1/1024 sample) and subsamples were counted to 300 – 500 individuals of adult copepods, copepodites, cladocerans or polychaete larvae.
Temperature and salinity were measured every 10 days in the vertical profile using a CTD (SIS CTD, FSI CTD and Mini CTD) and values were averaged over the upper 25 m. Secchi depth was measured using a Secchi disc according to the HELCOM guidelines for monitoring of water transparency (HELCOM, 2019). Monthly pH and CHLa data were obtained from the Finnish Environment Institute’s VESLA database. CHLa was extracted from water samples using ethanol (HELCOM, 2025) and pH was measured using a glass electrode. Both pH and CHLa were measured at discrete depths of 1, 5, 10, 15 and 20 m and the averages were used for further analysis.
Files and variables
File: final_new_revisions_script.R
Description: R script of the time series analysis conducted for the associated manuscript.
File: storfjarden_time_series.csv
Description: Time Series Data from Tvärminne Storfjärden
Variables
- Date: Sampling Date
- Acartia_AD: Combined biomass of adult specimen
- Acartia_COP: Combined biomass of undefined copepodite stages
- Acartia_COP_1-3: Combined biomass of copepodite stages 1-3
- Acartia_COP_4-5: Combined biomass of copepodite stages 4-5
- Acartia_NA: Combined biomass of specimen of undefined life stage
- Acartia_NP: Combined biomass of nauplii
- Acartia_Total: Combined biomass of all life stages
- Branchiopoda_NA: Combined biomass of specimen of undefined life stage
- Branchiopoda_Filter_AD: Combined biomass of adult specimen
- Branchiopoda_Filter_JUV: Combined biomass of juvenile stages
- Branchiopoda_Filter_NA: Combined biomass of specimen of undefined life stage
- Branchiopoda_Filter_NS: Combined biomass of specimen of undefined life stage
- Branchiopoda_Filter_Total: Combined biomass of all life stages
- Branchiopoda_Predatory_AD: Combined biomass of adult specimen
- Branchiopoda_Predatory_JUV: Combined biomass of juvenile stages
- Branchiopoda_Predatory_NA: Combined biomass of specimen of undefined life stage
- Branchiopoda_Predatory_NS: Combined biomass of specimen of undefined life stage
- Branchiopoda_Pred_Total: Combined biomass of all life stages
- Eurytemora_AD: Combined biomass of adult specimen
- Eurytemora_COP_1-3: Combined biomass of copepodite stages 1-3
- Eurytemora_COP_4-5: Combined biomass of copepodite stages 4-5
- Eurytemora_NP: Combined biomass of nauplii
- Eurytemora_Total: Combined biomass of all life stages
- Keratella_NA: Combined biomass of specimen of undefined life stage
- Keratella: Combined biomass of specimen
- Keratella_Total: Combined biomass of all life stages
- Synchaeta_NA: Combined biomass of specimen of undefined life stage
- Synchaeta: Combined biomass of specimen
- Synchaeta_Total: Combined biomass of all life stages
- Temora_AD: Combined biomass of adult specimen
- Temora_COP_1-3: Combined biomass of copepodite stages 1-3
- Temora_COP_4-5: Combined biomass of copepodite stages 4-5
- Temora_NA: Combined biomass of specimen of undefined life stage
- Temora_NP: Combined biomass of nauplii
- Temora_NS: Combined biomass of specimen of undefined life stage
- Temora_Total: Combined biomass of all life stages
- Mean_Temp: average temperature in °C over the top 25 m
- Mean_Salinity: average salinity over the top 25 m
- mean_NH4: average NH4 in µg/L over the top 25 m
- mean_NO2: average NO2 in µg/L over the top 25 m
- mean_NO3: average NO3 in µg/L over the top 25 m
- mean_PO4: average PO4 in µg/L over the top 25 m
- mean_Si: average Si in mg/L over the top 25 m
- mean_TP: average TP in µg/L over the top 25 m
- mean_TN: average TN in µg/L over the top 25 m
- mean_pH: average pH over the top 25 m
- mean_CHL: average CHLa in µg/L over the top 25 m
- mean_Oxygen: average O2 in mg/L over the top 25 m
- Secchi: Secchi depth in m
- doy: Day of year
- year: year
- month: month
- year,cont: year as continuous variable
- bio_tot: total combined zooplankton biomass
- Copepoda_Total: combined biomass of all genera/feeding modes
- Branchiopoda_Total: combined biomass of all genera/feeding modes
- Rotifera_Total: combined biomass of all genera/feeding modes
- mean_sal_resid: residual values of salinity after applying a generalized additive model
- mean_temp_resid: residual values of temperature after applying a generalized additive model
- mean_chl_resid: residual values of CHLa after applying a generalized additive model
- mean_ph_resid: residual values of ph after applying a generalized additive model
- mean_secchi_resid: residual values of secchi depth after applying a generalized additive model
Code/software
Microsoft Excel, Rstudio