ALBERT

Description: 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.

Description: 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.

Description: We examined the growth response of a brackish snail (Hydrobiidae) against multiple temperature treatments in a mesocosm located beside the Alfred Wegener Institute Wadden Sea Station on Sylt (55°01′19.2″N, 8°26′17.7″E). Bulk sediments were collected south of Pellworm (54° 31' 55.83"N, 8° 42' 40.36"E) at low tide on March 22, 2022, transferred to mesh-lined crates and introduced to mesocosm tanks (170 cm × 85 cm × 1800 L). Experimental warming treatments were conducted using three heaters per tank (Titanium heater 500 W, Aqua Medic, Bissendorf, Germany). The full specifications for the mesocosms are already published (Pansch et al., 2016). Throughout the experimental warming period, four sampling events (March 30, April 25, May 24, June 20) were conducted to core sediments. Sediment cores were washed and sieved (1mm mesh size) to disaggregate infauna. Individuals were separated for the common hydrobiid mudsnail, which were subsequently imaged in groups on a typical petri plate under stereomicroscopy. A semi-automatic object segmentation and size measurement approach was developed to rapidly differentiate and measure individuals from images. Segmentation was highly accurate and precise against manual length measurements (end-to-end; mm) collected in ImageJ for 4595 snails. Scaling the segmentation method across the full dataset estimated 〉40,000 snails and presented a complex species-specific response to warming. The enclosed dataset represents all raw, processed, and segmented images (n= 3201) produced by this study.

Description: 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.

Description: Microbial food web organisms are at the base of the functioning of pelagic ecosystems and support the whole marine food web. They are very reactive to environmental changes and their interactions are modified in response to different productive periods such as phytoplankton bloom and non-bloom as well as contrasted climatic years. To study ecological associations, identify potential interactions between microorganisms and study the structure of the microbial food web in coastal waters, a weekly monitoring was carried out in the Thau Lagoon on the French Mediterranean coast. The monitoring lasted from winter to late spring during two contrasting climatic years, a typical Mediterranean (2015) and a year with an extreme warm winter (2016). Correlation networks comprising 110 groups/taxa/species were constructed to characterize potential possible interactions between the microorganisms during bloom and non-bloom periods. Complex correlation networks during the bloom and dominated by negative intraguild correlations and positive correlations of phytoplankton with bacteria. Such pattern can be interpreted as a dominance of competition and mutualism. In contrast, correlation networks during the non-bloom period were less complex and mostly dominated by tintinnids associations with bacteria mostly referring to potential feeding on bacteria, which suggests a shift of biomass transfer from phytoplankton-dominated food webs during bloom to more bacterioplankton-based food webs during non-bloom. Inter-annual climatic conditions significantly modified the structure of microbial food webs. The warmer year favored relationships among smaller group/taxa/species at the expense of large phytoplankton and ciliates, possibly due to an intensification of the trophic cascade with a potential shift in energy circulation through microbial food web. Our study compares a typical Mediterranean spring with another mimicking the prospected intensification of global warming; if such consideration holds true, the dominance of future coastal marine ecosystems will be shifted from the highly productive herbivorous food web to the less productive microbial food web.

Description: The sustainable management of social–ecological systems (SESs) requires that we understand the complex structure of relationships and feedbacks among ecosystem components and socioeconomic entities. Therefore, the construction and analysis of models integrating ecological and human actors is crucial for describing the functioning of SESs, and qualitative modeling represents an ideal tool since it allows studying dependencies among variables of diverse types. In particular, the qualitative technique of loop analysis yields predictions about how a system’s variables respond to stress factors. Different interaction types, scarce information about functional relationships among variables, and uncertainties in the values of the parameters are the rule rather than exceptions when studying SESs. Accordingly, loop analysis seems to be perfectly suitable to investigate them. Here, we introduce the key aspects of loop analysis, discuss its applications to SESs, and suggest it enables making the first steps toward the integration of the three dimensions of sustainability.

Description: Key traits of functional biodiversity are examined for 31,134 species of fishes. These traits are maximum body weight, productivity, and trophic level. A new, simple framework is presented that shows the combined usage of these traits, in ordinal categories, for close to 90% of extant species of fishes. Most species are clustered tightly along an evolutionary axis in size-productivity-trophic space (SPT-space) from few large, evolutionary old species with very low productivity to many medium-sized newly evolved species with high productivity, superseding Cope’s rule of a within-lineages trend towards larger size and lower productivity. The across-lineages evolutionary axis is also found in the subsets of marine, freshwater, and Arctic species. Another notable prediction is the five-fold increase in top predators in Arctic waters in 2100, which could cause the extinction of endemic species. The main purpose of this study is to demonstrate the usefulness of the SPT-framework for comparing functional biodiversity patterns in ecosystems by salinity, geography or time. Also, the SPT-framework was used to explore correlations with other traits such as body shape, and to display the position of individual species, represented by pictograms of body shape and habitat, within SPT-space.

Description: Ecosystem models need to capture biodiversity, because it is a fundamental determinant of food web dynamics and consequently of the cycling of energy and matter in ecosystems. In oceanic food webs, the plankton compartment encompasses by far most of the biomass and diversity. Therefore, capturing plankton diversity is paramount for marine ecosystem modelling. In recent years, many models have been developed, each representing different aspects of plankton diversity, but a systematic comparison remains lacking. Here we present established modelling approaches to study plankton ecology and diversity, discussing the limitations and strengths of each approach. We emphasize their different spatial and temporal resolutions and consider the potential of these approaches as tools to address societal challenges. Finally, we make suggestions as to how better integration of field and experimental data with modelling could advance understanding of both plankton biodiversity specifically and more broadly the response of marine ecosystems to environmental change, including climate change.

Description: Legal requirement in Europe asks for Ecosystem-Based Fisheries Management (EBFM) in European seas, including consideration of trophic interactions and minimization of negative impacts of fishing on food webs and ecosystem functioning. This study presents the first mass-balanced ecosystem model focused on the western Baltic Sea (WBS). Results show that heavy fishing pressure exerted on the WBS has forced top predators such as harbour porpoise and cod to cover their dietary needs by shifting from forage fish to other prey or find food outside of the model area. The model was then developed to explore the dynamics of four future fishery scenarios: (1) business as usual (BAU), (2) maximum sustainable fishing (F = FMSY), (3) half of FMSY, and (4) EBFM with F = 0.5 FMSY for forage fish and F = 0.8 FMSY for other fish. Simulations show that BAU would perpetuate low catches from depleted stocks with a high risk of extinction for harbour porpoise. In contrast, the EBFM scenario would allow the recovery of harbour porpoise, forage fish and cod with increases in catch of herring and cod. EBFM promotes ecosystem resilience to eutrophication and ocean warming, and through the rebuilding of commercial stocks increases by more than three times carbon sequestration compared to BAU. The model provides an interrelated assessment of trophic guilds in the WBS, as required by European law to assess whether European seas are in good environmental status.