Five years of high-frequency data of phytoplankton zooplankton and limnology from a temperate eutrophic lake

Abstract

This study presents a comprehensive dataset from Lake Greifen, Switzerland, collected between April 2018 and June 2023, using high-frequency automated monitoring systems. The dataset integrates meteorological data, nutrient chemistry, water column profiles for water physics, and plankton underwater imaging, offering insights into the lake's physical and biological processes. A dual-magnification dark field underwater microscope captured hourly plankton dynamics at 3 m depth, providing size, shape, and taxonomic information. A profiler with a multiparametric probe monitored water temperature, oxygen, and other key parameters from 1 to 17 m depth, while weekly nutrient sampling complemented the measurements. Data processing involved rigorous cleaning protocols to remove technical artefacts, ensuring data quality. Our dataset showcases the utility of integrating different approaches for high-frequency monitoring to detect lake temporal processes, from phytoplankton blooms to zooplankton vertical migration and seasonal shifts in water column stability. This dataset provides a unique resource for studying limnology and plankton community ecology. All data and related processing codes are publicly available for further research, supporting interdisciplinary studies.

Fig. 1

The data: Overview of water analyses conducted, and parameters observed. Figure inspired by.

Fig. 2

Time series of all meteorological parameters measured from 2018 until June 2023. Each parameter (y-axis) is indicated in the grey box above each panel.

Fig. 3

DSPC data processing from whole frames to individual-level trait information and classification. (a) From each frame, all individual objects are cropped into regions of interest (ROI). (b) The name of each ROI contains information about the image itself. (c) Images are processed to extract traits and classification (see Data Processing Section).

Fig. 4

Time series of all CTD parameters measured from 2018 until June 2023. The horizontal line represents the depth at which the DSPC is installed (3 m). For visibility, turbidity, phycoerythrin and phycocyanin are in Log₁₀ scale. A non-log figure can be found in SI Fig. S2.

Fig. 5

Nutrient chemistry samples taken during the study period 2019–2023. Samples were generally taken (bi-)weekly. Here we plot the main samples excluding exceptional samples that do not fall into one of the categories in the plot. Three = 3 m depth, max chl = depth at Chlorophyll a maximum, integrated = 0–18 m integrated, fifteen = 15 m depth.

Fig. 6

Daily values of a subset of meteorological parameters measured in 2018–2021 at the monitoring platform and the MeteoSwiss station in Fluntern. Each parameter (y-axis) is indicated in the grey box above each panel. Total precipitation at the platform is calculated as the mean precipitation intensity (mm/h) per day multiplied by 24. Note that the total precipitation is in Log₁₀ scale.

Fig. 7

Time series of two common taxa in the (a) 5.0x magnification (cryptophyceae) and (b) 0.5x magnification (Daphnia sp.). In 2018 (grey area), the distribution of sampling time across the day was different from the rest of the time series.

Fig. 8

Comparison of ROI/sec from both magnifications on Asterionella sp., which has a colony diameter of about 100 μm and lies well within the detection range of both magnifications. The slope of the linear relationship between the two magnifications (daily values 2019 - June 2023) is illustrated as a blue smooth line with the theoretical slope of 20 as a dashed line. (a) All data points and the 99% and 95% quantiles as coloured blocks, (b) 99% quantile, (c) 95% quantile.

Fig. 9

Daily values of a subset of physicochemical parameters measured in 2018–2023 at the monitoring platform by the CTD probe and monthly values measured by cantonal authorities. Each parameter (y-axis) at different depths is indicated in the grey box above each panel.

Fig. 10

PAR profiles by the CTD probe at the monitoring platform. (a) Schematic illustration of the CTD setup below the platform and its influence on PAR measurements. The CTD probe descends below the platform and is therefore shaded in the first few metres. (b) 75 profiles across the 5 years and the influence of the month on the shape of the depth-PAR curve.