Department Aquatic Ecology

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.

The degradation of climate and biodiversity are two major crises humans are facing and for which rapid action is needed. Both crises are partially linked and susceptible to threaten nature's contribution to peoples (NCPs). Hence, it is essential to find efficient strategies for protecting key areas for both biodiversity and NCPs for a sustainable future. Studies at various scales have already used species distributions and NCP maps to identify the most optimal areas for safeguarding both components. Yet, an evaluation of how changes in species distributions could affect NCPs was still lacking. Here, based on a recently established table of relationships between more than 2,000 native vertebrate and tracheophyte species and 17 NCPs, we propose and illustrate a novel approach to predict the spatial distribution of NCPs from individual species predictions for the current period and four future time-scenarios in the Western Swiss Alps. Predictions of the different NCPs and their categories show varying degrees of spatial correlation, with some NCPs revealing very distinct patterns across time-scenarios. An overall decrease of NCP value is predicted for each future time-scenario. According to our results, NCPs would not increase at higher elevations in the subalpine and alpine belts and would remain high at mid-elevations in the montane belt along river valleys. Our study highlights the potential to predict NCPs directly from species predictions in biodiversity assessments, allowing a better understanding and a better anticipation of the way species contribute to NCP and human well-being. The species-based NCP prediction approach we propose constitutes a major new asset to improve spatial conservation planning, but the development of such species-NCP tables should continue, and larger databases be compiled.

The use of biodegradable plastics as an alternative to conventional non-degradable synthetic polymers is gaining market to reduce plastic pollution, however, their biodegradability is not unconditional. In this study, we hypothesized that planktonic protists (nanoflagellates and ciliates) increase the degradation of the biodegradable PLGA (poly(lactic-co-glycolic) acid) due to particle uptake. We conducted uptake and degradation experiments using PLGA microspheres of 4.9 ± 2.8 μm diameter and the microbial planktonic community from the Baltic Sea. We found that planktonic protists ingested PLGA of different sizes, with ciliates displaying higher clearance rates and ingesting larger particles compared to nanoflagellates. In addition, we observed a more pronounced decrease in PLGA concentration and particle size over time in the presence of seawater containing microbial plankton compared to a control with only ultrapure water, suggesting that the presence of these organisms increases the rate of degradation of PLGA in marine ecosystems. Altogether, these results indicate that microbial plankton enhances the degradation of biodegradable microplastics like PLGA, specifically through rapid uptake by planktonic protists. These findings highlight the role of particle ingestion by planktonic protists in the fate of the so-called biodegradable plastics when they enter aquatic ecosystems.