The data were generated during an experiment simulating different frequencies of heatwaves (zero, one and three) in late spring/summer 2015. The experiment was carried out at the Kiel Outdoor Benthocosm (KOB) of GEOMAR Helmholtz Centre for Ocean Research Kiel, located at the Kiel Fjord.
The biomass of filamentous algae was quantified from the most abundant genus occurring inside the tanks, i.e. Ceramium sp. The biomass of Zostera marina and Fucus vesiculosus was estimated from growth rates measurements carried out every 15 days. The biomass of all macrophytes was converted to carbon using specific carbon contents measured concomitantly with stable isotopes (https://doi.pangaea.de/10.1594/PANGAEA.966179). Respiration and primary production measurements were carried out on 09.08.2015 for filamentous algae, and on 12.08.2015 for Fucus vesiculosus. To execute these measurements, organisms were kept in gas-tight cylindrical chambers equipped with sensor spots for non-invasive oxygen measurements, which allowed continuous oxygen logging. Throughout the measurements, the chambers were kept inside the KOB tanks to maintain the temperature. The oxygen values were converted to carbon and normalized by the area of the tank (1.53 m2) per day. Note that the data of net primary production and respiration rates of the Z. marina were previously published (https://doi.org/10.1594/PANGAEA.904632). The carbon flux refers to the exports, i.e. biomass that was floating in the tanks, which was considered as carbon leaving (i.e. exported outside of) the system but still usable. The material to quantify the exports was collected every seven days, separated accounting for the contribution of each macrophyte group, dried at 80 °C until the biomass was constant and weighted. The dry weight was converted to carbon using the specific carbon contents measured concomitantly with stable isotopes (https://doi.pangaea.de/10.1594/PANGAEA.966179), and normalized by the area of the tank (1.53 m2) per day.
The data refer to an experiment simulating different frequencies of heatwaves (zero, one and three) in late spring/summer 2015. The experiment was carried out at the Kiel Outdoor Benthocosm (KOB) of GEOMAR Helmholtz Centre for Ocean Research Kiel, located at the Kiel Fjord.
The organisms were collected from the mesocosm tanks, stored at -80 °C, dried at 60 °C for at least 48 hours, and ground with agate mortar and pestle. The ground material was subsampled, weighed and placed into tin capsules (3.2 × 4.0 mm, Hekatech, Wegberg, Germany). These samples were analysed with an elemental analyser system (NA 1110, Thermo, Milan, Italy) connected to a temperature-controlled gas chromatography oven (SRI 9300, SRI Instruments, Torrance, CA, USA) and to an isotope-ratio mass spectrometer (DeltaPlus Advantage, Thermo Fisher Scientific) as described in Hansen et al. (2009), https://doi.org/10.1002/rcm.4267.
Benthic invertebrate samples were taken directly in the field via hand-netting in four ditches and three ponds (defined as water bodies with a maximum extent of one hectare) in October and November 2020. Sampling was carried out in Brandenburg in Germany in the region Havellaendisches Luch. The landscape is characterized by an intensively maintained ditch system that was created for industrial agricultural production during 1980s. Additionally, the landscape is characterized by a large number of small standing water bodies (kettle holes, ponds), which were formed during the last glacial period. A detailed description of the area can be found in Trau & Lorenz, 2024. Invertebrate samples were analysed for the stable isotopes of carbon and nitrogen. The data set includes data from 35 families. The whole animal was used for the analysis of stable isotopes of carbon and nitrogen. Analyses were performed on a Thermo Delta V isotope ratio mass spectrometer (IRMS) interfaced to a NC2500 elemental analyser by the Cornell University Stable Isotope Laboratory (https://cobsil.cornell.edu/). The dataset was used to evaluate isotopic niches of functional feeding groups (collector/gatherer, collector/filterer, grazer/scraper, shredder, predator and omnivore) in the two water body types (pond and ditch), in order to evaluate effects of agriculture (nutrient concentrations and pesticide residues) on the isotopic niches (Trau et al. 2025, under review).
Stable isotopes (a: δ15N, b: δ13C) of G. childressi that experienced different nutritional regimes (CH4: 'M', algae + CH4: MA', only algae: 'A') in our culture. As reference, t0 animals were sampled upon arrival at GEOMAR after spending 2 months post-capture at Charles Fisher's 'deep-sea lab' aquarium system, Pennsylvania State University
The data were generated during an experiment simulating different frequencies of heatwaves (zero, one and three) in late spring/summer. The experiment was carried out at the Kiel Outdoor Benthocosm (KOB) of GEOMAR Helmholtz Centre for Ocean Research Kiel, located at the Kiel Fjord.
The consumers were collected from the mesocosm tanks and the respiration rates were measured in the lab. The measurements were carried out on 10.08.2015 (Idotea balthica), 11.08.2015 (Littorina littorea) and 14.08.2015 (Gammarus sp.). The organisms were kept in gas-tight bottles equipped with sensor spots for non-invasive oxygen measurements, which allowed continuous oxygen logging. Throughout the measurements, the bottles were kept in water baths with temperature set to 19.7 °C, which was the temperature all the KOB tanks were exposed to at the time of the measurements. The oxygen values were converted to carbon and normalized by the area of the tank (1.53 m2) per day.