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Quantified community composition of aquatic insect larvae with urbanization and environmental parameters in artificial microhabitats, Salzburg, June-August 2021

Urbanization affects ecological communities but urban ecology has mostly focused on large and charismatic species. Water-filled tree holes and other ephemeral small standing waters in cities constitute unique but inconspicuous breeding habitats for a range of insects. Their biodiversity is not well known and how their communities respond to increased urbanization in particular, has rarely been studied. Using a Citizen Science Project, we investigated how urbanization (measured as imperviousness, human population density and altered temperature), additional environmental parameters (pH, electric conductivity) and detritus serving as a food source affected larval insect communities in artificial aquatic microhabitats. We found that these habitats were colonized quickly by a range of insect taxa. Their community abundance, richness and decomposition rates were largely stable across different levels of urbanization. Fine detritus content increased larval abundance. Community composition shifted strongly with urbanization. The most abundant and frequent species in our study, the exotic mosquito species Aedes japonicus, responded negatively to imperviousness. Aquatic microhabitats could be shown to be important habitats for aquatic insects in cities. However, their community composition may change with increased urbanization. As our results showed, exotic species such as mosquitoes may dominate the communities in these habitats. In the case of vector species, high abundances may affect human and animal health via increased pathogen transmission. Therefore, we suggest raising awareness about potential risks of these habitats and possible measures preventing the establishment and spread of harmful species, while still supporting native biodiversity in urban spaces.

KOSMOS 2023 Helgoland mesocosm study on ocean alkalinity enhancement: phytoplankton and microzooplankton abundance and biomass data

This dataset contains species-resolved phytoplankton and microzooplankton abundance and biomass data from the KOSMOS 2023 Helgoland mesocosm experiment conducted in the coastal waters off Helgoland Island in the North Sea, Germany. The experiment investigated the effects of Ocean Alkalinity Enhancement (OAE) on plankton communities during the development of a natural spring bloom. Six mesocosms (~6 m³) were subjected to an immediate dilution OAE scenario, establishing an alkalinity enhancement gradient ranging from ΔTA 0 to 1250 µmol kg⁻¹ in increments of 250 µmol kg⁻¹ through calcium-based alkalinity addition. The dataset includes taxonomically resolved phytoplankton and microzooplankton abundance (cells mL⁻¹), carbon biomass (µg C L⁻¹), functional group classifications, and World Register of Marine Species (WoRMS) taxonomic identifiers. Associated carbonate chemistry measurements, including total alkalinity (TA), dissolved inorganic carbon (DIC), pH, fugacity of carbon dioxide (fCO₂), salinity, temperature, and calculated ΔTA values are provided for each sampling event.

Experiment on Germination Success of Injection-Based Zostera marina Sowing Methods in Kiel Fjord

Seed-based restoration is a promising approach to accelerate the slow natural recolonization of Zostera marina meadows. In this study, seed-based restoration was investigated through the injection of seeds into the sediment using syringes. Parallel laboratory and field experiments were conducted to examine germination success over time under both simulated and natural field conditions. A field experiment was conducted in the Kiel Fjord (Baltic Sea), next to Seebar. The experimental setup consisted of three quadrats (3x3 m) divided into 36 plots (0.5x0.5 m). Quadrat 1 was located at 54° 20' 52.10 N, 10° 09' 04.10 E, quadrat 2 at 54° 20' 52.70 N, 10° 09' 04.20 E and quadrat 3 at 54° 20' 52.30 N, 10° 09' 04.70 E. In each plot, a seed amount equivalent to the weight of either 100 or 500 Zostera marina seeds was sown, based on the average seed weight determined prior to the experiment. Seeds were collected at two sites in Laboe and Falckenstein (Kiel Fjord) in July 2023 by snorkelers and scientific divers (Laboe: 54° 24' 48.53 N, 10° 13' 29.91 E; Falckenstein: 54° 23' 31.36 N, 10° 11' 31.15 E). They were overwintered in climate cabinets in darkness at 4°C and a salinity of 32 PSU, where they rotated every 6 hours for 1 minute. Different treatment combinations were tested, involving the factors Sowing Method (syringe (100 ml) with agar medium or Hand-Sown), Sowing Depth (2 cm or 4 cm), Origin of Seeds (Falckenstein or Laboe), and Seed Density (100 or 500 seeds per plot). The Hand-Sown method served as a control. To this end, a small trench with 2-4 cm depth was manually dug using a finger. Seeds were sown into the trench, which was then gently filled with sediment from both sides. For the syringe treatment, seeds were injected into the sediment embedded in an agar medium prepared by cooking Baltic Sea water with 1.8% agar (Agar-Agar, BioScience Grade, pulv., Carl Roth). Each syringe contained 90 ml crumbly agar, 10 g autoclaved sediment, 100 or 500 seeds and depending on the treatment either 1 g charcoal powder or nutrients (P and N) were added. For the nutrients, according to the Redfield ratio N:P = 16:1, 100 μL of nitrogen and 10 μL of phosphorus were used per 90 mL of agar. Each syringe contained 100 or 500 seeds and included either the addition of nutrients (P and N) or charcoal powder or no further additions. The seeds were sown by scientific divers on March 12, 14 and 18, 2024 and seedlings were counted on April 23, 2024 and May 23, 2024 to determine the germination rate and evaluate which sowing method was the most successful.

Microbial sulfate reduction rates, geochemical micro profiles and benthic chamber experiment data in the Kiel Bight, SW Baltic Sea from 2023 to 2025

This dataset collection presents measurements of microbial sulfate reduction rates (SRR), mircrosensor profiles, and benthic chamber experiments from eight stations, in Kiel Bight, near Fehmarn and Flensburg Fjord from 2023 to 2025. Sediment cores were recovered using multicorer (MUC), minicorer (MIC) or Rumohr lot (RL), with multiple core liners (MUC/MIC) used per deployment for microbial, geochemical, and sensor analysis. The dataset provides the first spatial and temporal overview of sulfide production in sediment and water column of Kiel Bight, small-scale putatively microbial influenced vertical gradients of the upper sediment, and flux rates between sediment and bottom water. Further geochemical data from the same deployments can be found in Spiegel et al. 2026 https://doi.pangaea.de/10.1594/PANGAEA.988013. Together these datasets enable assessments of microbial-geochemical controls on sulfide production, retention, and emission to the bottom water of Kiel Bight under changing regimes.

Experiment on Germination Success of Injection-Based Zostera marina Sowing Methods in Aquaria

Seed-based restoration is a promising approach to accelerate the slow natural recolonization of Zostera marina meadows. In this study, seed-based restoration was investigated through the injection of seeds into the sediment using syringes. Parallel laboratory and field experiments were conducted to examine the germination success over time under both simulated and natural field conditions. A laboratory experiment was conducted in the climate chambers of GEOMAR Helmholtz Centre for Ocean Research Kiel. Twelve replicate aquaria, each containing 6 boxes of 18 cm*13 cm*18 cm, were set up in a climate chamber. Each plastic box in the aquaria was filled with 6 cm of sandy sediment collected from sandbanks next to seagrass meadows in Falckenstein near Kiel (54°23'39.4N 10°11'23.6E). For sterilization, the sediment was autoclaved at 121°C for 20 minutes before use. Water was changed weekly, with approximately 30% replaced by filtered (50 μm and 5 μm filter cascade) Baltic Sea water with an ambient salinity ranging from 14-16 PSU. The chamber simulated field conditions typical for the season, with 12 hours of light per day and a temperature of 10°C. In each box, a seed amount equivalent to the weight of 100 Zostera marina seeds was sown, based on the average seed weight determined prior to the experiment. Seeds were collected at two sites in Laboe and Falckenstein (Kiel Fjord) in July 2023 by snorkelers and scientific divers (Laboe: 54° 24' 48.53 N, 10° 13' 29.91 E; Falckenstein: 54° 23' 31.36 N, 10° 11' 31.15 E). They were overwintered in climate cabinets in darkness at 4°C and a salinity of 32 PSU, where they rotated every 6 hours for 1 minute. Different treatment combinations were tested, involving the factors Sowing Method (syringe (100 ml) with agar medium or Hand-Sown), Sowing Depth (2 cm or 4 cm), Origin of Seeds (Falckenstein or Laboe), and Fertilization of the Sediment (from the beginning, after germination, or none at all). The Hand-Sown method served as a control. To this end, the box was filled with about 4cm autoclaved sandy sediment. Then the seeds were evenly distributed on the surface and covered with either 2 cm or 4 cm of sediment before being gently lowered into the aquarium. For the syringe treatment, seeds were injected into the sediment embedded in an agar medium prepared by cooking Baltic Sea water with 1.8% agar (Agar-Agar, BioScience Grade, pulv., Carl Roth). Each syringe contained 90 ml crumbly agar, 10 g autoclaved sediment, 100 seeds and depending on the treatment, either 1g charcoal powder, nutrients (P and N) or no further additions. For the nutrients, according to the Redfield ratio N:P = 16:1, 100 μL of nitrogen and 10 μL of phosphorus were used per 90 mL of agar. There were three timing treatments for "Timing of Nutrients in the Sediment". "Nutrients from Beginning", "Nutrients after Germination" and "no Nutrients". The treatment was the same for all boxes within one aquarium to avoid potential influence on the surrounding water. As fertilizer "osmocote Langzeitdünger 6 Monate" (N P 19+9) was used. In the boxes with "Nutrients from Beginning", two pellets were inserted with tweezers into the sediment directly after sowing. In the boxes with "Nutrients after Germination", the same treatment started on April 29, 2024, after many of the seedlings had already developed some green leaves. The seeds were sown on March 4, 2024, and from March 21 to May 25, 2024, emerging seedlings were counted three times per week. Seedlings with only cotyledons and seedlings with developed green leaves were counted together in the beginning and separately from April 24, 2024, onwards.

Ecosystem functions of rare arable plants - field experiment: Carabidae data

Partly taken from the materials and methods of https://doi.org/10.1016/j.baae.2022.12.003: To compare the activity densities of ground-dwelling predators between treatments with and without RAPs, carabids were sampled using pitfall traps, which were set up after each round of aphid counting (one per plot, twice per year; Brown & Matthews, 2016). The traps (with a volume of 400 ml and a width of 90 mm) were filled with a mixture of water and ethylene glycol (1:1; 120 ml) and dug at ground level into the middle of each plot. The traps were covered with a plastic roof and a metal grid (15 × 15 mm grid size) to avoid overflowing during rain and accidental rodent catches (Császár et al., 2018). The traps were activated for 7 days. Subsequently, all arthropods were transferred into 70% ethanol. Carabids were identified to species according to Hůrka (1996). Carabid feeding behavior was classified according to Homburg et al. (2014). To simplify the dataset, carabid feeding behavior was classified as predominantly granivorous (species mainly feed on seeds and fruits) or as carnivorous/omnivorous, because carnivorous and omnivorous species are potentially feeding on aphids and other non-plant material.

Sensor data from a benthic chamber experiment in the Kiel Bight, SW Baltic Sea from 2025

This dataset consists of sensor data from field experiments with time-series point measurements. These benthic MiniChamber experiments were run at five stations for 20 h during cruise EMB374 (04.09.2025 - 13.09.2025). An O2 optode with integrated temperature sensor (Aanderaa, Norway), as well as pH and sulfide micro sensor (Unisense, Denmark), were measuring within the benthic chamber during the 20 h experimental run. The data set will be used to highlight similarities and differences in the benthic system of the Kiel Bight. Oxygen respiration and sulfide flux rates from the benthic chamber can be extrapolated to larger areas of Kiel Bight, providing insights into more widespread occurrences of sulfide emissions.

Positivnetz Lang-LKW Hamburg

Der Datensatz beinhaltet den Teil des Hamburger Straßennetzes, der für die Befahrung mit Lang-Lkw freigegeben ist (Positivnetz). In Hamburg beschränkt sich dieses Straßennetz auf die Bundesautobahnen für den Transit zwischen den Bundesländern, auf einige Strecken im Hafenbereich sowie auf ausgewählten Stadtstraßen zu Gewerbe- und Industriegebieten. Das Befahren außerhalb der angegebenen Stadtstraßen ist nicht gestattet. Zusätzliche Informationen zu dem dazugehörigen Feldversuch des Bundesministeriums für Verkehr und digitale Infrastruktur (BMVI) sowie zu der zugrundeliegenden Verordnung und Ausnahmen für spezielle Lang-Lkw-Typen können unter folgendem Link eingesehen werden: http://www.hamburg.de/lang-lkw/

Die Wirkung von Muellkompost auf landwirtschaftlich genutzte Flaechen

In einem Feldversuch wurden unterschiedliche Mengen und Arten von Muellkompost angewendet. In regelmaessigen Abstaenden wird der Einfluss dieser Materialien auf die chemischen und physikalischen Eigenschaften des Bodens ermittelt, gleichzeitig werden Ertragsfeststellungen durchgefuehrt.

Produktion und Konsumption (Flüsse) der klimarelevanten Spurengase, Lachgas und Methan in einem Dauergrünland unter steigender atmosphärischer CO2-Konzentration

Außer dem bekannten Treibhausgas Kohlendioxid (CO2) existieren weitere stark klimawirksame Spurengase biologischen Ursprungs, z.B. Lachgas (N2O) und Methan (CH4), die mikrobiell im Boden produziert (N2O, CH4) oder im Falle des Methans auch verbraucht (oxidiert) werden. Die steigende atmosphärische CO2-Konzentration kann sich über die Pflanzen in vielfacher Weise auf die bodenmikrobiellen, Spurengasproduzierenden Prozesse auswirken. So ist beispielsweise nachgewiesen worden, dass der Wasserverbrauch der Pflanzen unter erhöhtem CO2 häufig sinkt und die Abgabe von leicht zersetzbarem Kohlenstoff an den Boden (Wurzelexudation) steigt. Beides könnte die Denitrifikation und damit die N2O-Produktion begünstigen, ebenso die Methanproduktion, wenn im Boden anaerobe Bedingungen (z.B. durch Überflutung) eintreten. Steigende Bodenfeuchte würde zugleich die Sauerstoff-abhängige Methanoxidation im Oberboden hemmen. Zu diesem Thema existieren bislang weltweit nur Kurzzeit- und Laborstudien. Im hier vorgestellten Projekt werden im Freilandexperiment die Langzeitauswirkungen steigender atmosphärischer CO2-Konzentrationen über das System Pflanze-Boden auf die Flüsse der klimawirksamen Spurengase N2O und CH4 in einem artenreichen Dauergrünland untersucht. Hierzu gelangt ein im Institut für Pflanzenökologie neuentwickeltes Freiland-CO2-Anreicherungssystem (FACE) zur Anwendung, bei dem die CO2-Konzentration in drei Anreicherungsringen seit Mai 1998 um etwa 20 Prozent gegenüber den drei Kontrollringen erhöht wurde. Über die Jahresbilanzierungen der Spurengasflüsse sowie über begleitende Prozessstudien soll geklärt werden, wie und auf welche Weise erhöhtes CO2 auf die N2O- und CH4-Spurengasflüsse rückwirkt. Die ersten Ergebnisse zeigen deutlich, dass in einem etablierten artenreichen Ökosystem wie dem untersuchten Feuchtgrünland zuerst die unterirdischen Prozesse auf die steigenden CO2-Konzentrationen reagierten (Bestandesatmung). Die oberirdische Biomasse zeigte erst nach etwa 1,5 Jahren der CO2-Anreicherung einen signifikanten Zuwachs gegenüber den Kontrollflächen. Im Jahr 1997, vor dem Beginn der CO2 -Anreicherung, waren sowohl die N2O-Emissionen als auch die CH4 Flüsse auf den (späteren) Anreicherungs- und den Kontrollflächen fast identisch. Seit Beginn der Anreicherung hingegen sind die N2O-Emissionen vor allem während der Vegetationsperiode dramatisch angestiegen: auf 278 Prozent der Emissionen der Kontrollflächen. Die Methanoxidation war rückläufig unter erhöhtem CO2: Mittlerweile oxidieren die CO2 Anreicherungsflächen 20 Prozent weniger CH4 als die Kontrollflächen (Jahr 2000), wobei auch hier der größte Unterschied während der Vegetationsperiode auftrat. Eine erhöhte Bodenfeuchte kommt als Erklärung nicht in Frage, da sich diese nicht geändert hat.

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