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CO2 degassing from karstic springs in Southern Germany

This study examines characteristics of dissolved inorganic carbon (DIC) and partial pressures of CO2 characteristics (pCO2) in the source springs and headwaters of four karstic watersheds, via dissolved inorganic carbon concentration and stable carbon isotope measurements. All four spring sources are located in Southern Germany and were measured for water chemistry and stable isotopes with nearby headwater stream points, which were located up to 100 m downstream of the discharge points. Seasonal sampling covered winter, spring, summer, and autumn in 2018.

TOC, TIC, TN and TS contents and stable isotope signatures (δ13C of TOC, δ15N, δ34S) of fine-grained saltmarsh deposits of the barrier island Spiekeroog at the southern North Sea Coast

The dataset compiles total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN) and total sulfur (TS) contents and stable isotope signatures (δ13C of TOC, δ15N, δ34S) of fine-grained deposits (clay, loam) over sandy subsoils of the saltmarsh of the barrier island Spiekeroog at the southern North Sea coast. Sampling was performed in September 2016 along three transects spanning from the high saltmarsh to the pioneer zone. At each sample point, soil samples were taken from the first 5 cm of the upper part (top samples) and from the deepest 5 cm of the lower part (bottom samples) of the fine-grained deposit. If the fine-grained deposit layer had a thickness < 10 cm, only one bulk soil sample (single samples) was taken for the depth range equal to the deposit thickness. Samples were ground to fine powder. TIC was measured on oven-dried samples coulometrically with an Analytik Jena multi EA 4000 analyzer. The total carbon (TC), TN, and TS were analyzed using a Thermo Scientific Flash EA Isolink Elemental Analyzer. The TOC contents were calculated as the difference between TC and TIC. TOC, TN, and TS contents are reported based on the original dry mass. For isotope analysis, dried and homogenized samples were weighed in tin cups and combusted in a Thermo Scientific Flash EA Isolink Elemental Analyzer, connected to a Thermo Finnigan MAT 253 gas mass spectrometer via a Thermo Conflo IV split interface. The δ13C values of TOC were measured after decalcification of the ground powders with p. a. grade HCl. The TN and δ34S analysis were carried out on a separate aliquot of sample powder. The isotope results are given in the conventional δ-notation.

Spatial characterization of the composition of the isotope hydrobiogeochemistry along the Warnow River

A spatial study of the isotopic hydrobiogeochemical composition along the the Warnow River, which drains into the southern Baltic Sea, was carried out. The sampling took place on 29-30 April 2019 from the source up to the estuary. In addition to in situ physico-chemical parameters, surface water was sampled using a telescopic rod and a plastic beaker and preserved for further analysis. Major and trace elements and selected nutrients were measured using an ICP-OES (iCAP, 7400, Duo Thermo Fischer Scientific). Ammonium (NH4) and nitrate (NO3) concentrations were measured using a QuAAtro autoanalyzer system. Chloride (Cl) concentrations were measured by electrical potential difference precipitation with 0.05 M AgNO3. Dissolved inorganic carbon (DIC), and δ13CDIC were measured using an isotope gas mass spectrometer (MAT 253) coupled to a Gasbench II. Dissolved organic carbon (DOC) and δ13CDOC using an Elementar iso TOC cube with Thermo Electron MAT 253 mass spectrometry, δ18OH2O, and δ2HH2O using a CRDS system (laser cavity-ring-down-spectroscopy, Picarro L2140- I). δ34S and δ18O of SO4 using a gas-isotope mass spectrometer MAT253 (Thermo-Finnigan) with EA-Isolink (Thermo-Fisher-Scientific).

Stable isotope analysis of the common periwinkle Littorina littorea depending on infection status and seasonality

Littorina littorea was collected at the study site. The foot of Littorina littorea was used for stable isotope analysis (δ15N and δ13C). The stable isotope composition of possible food sources was also determined. Samples were taken in spring, summer and autumn. For the analysis a diet tissue discrimination factor (DTDF) of 2.4 for δ15N and 1.0 for δ13C was subtracted, respectively. The data in the sheet are the raw data without the DTDF.

Spatial pattern analysis for habitat composition and availability of food sources at Möltenort, Kiel Bight

The habitat at Möltenort was characterised with a 24 cm x 24 cm metal frame, which was thrown parallel to the coast 30 times within the 100 m transect. Coverage of Amphibalanus spp., Fucus vesiculosus, Gracilaria vermiculophylla, Mytilus spp., sand, stone, Ulva sp., and other ("other" indicating any category not mentioned in the list), was measured in 7 different percentage coverage groups (0, 1-5, 6-10, 11-20, 21-50, 51-75, or 76-100). Measurements were taken in spring, summer and autumn.

Habitat choice of the common periwinkle Littorina littorea depending on infection status and seasonality

Littorina littorea were collected from the habitat, screened for infection and marked before being released back into the environment. After 24 hours they were recollected and the habitat in which they were found was recorded. Their infection status was then checked by dissection.

Stable oxygen isotope ratios of pore water from IODP Site 347-M0059

The diet contribution and habitat selection of the common periwinkle Littorina littorea depending on infection with parasites and seasonality

The common periwinkle Littorina littorea is an ecologically important grazer and serves as the first intermediate host for several trematode species in the Baltic Sea, especially for the fluke Cryptocotyle lingua. In this series of experiments and analyses, we tested whether the food sources contributing to the diet and the habitat selection differ depending on the infection status of the periwinkle and the season. (1) A spatial pattern analysis was conducted to investigate the habitat composition and availability of food sources at the study site Möltenort, Kiel Bight (54.37°N, 10.19°E), (2) the habitat choice of the periwinkle was observed in-situ by a mark and recapture experiment, and (3) the composition of the diet of L. littorea (based on stable isotope composition of carbon and nitrogen isotopes) was analysed. All experiments were conducted in spring, summer and autumn.

Stabile Isotopenanalyse der Nahrung von Elateridenlarven

Die Nahrungswahl von Drahtwürmern (Coleoptera: Elateridae) im Agrarland und ihre Beeinflussung durch Umweltfaktoren analysiert mittels Stabiler Isotope. Als Drahtwürmer werden die Larven der Schnellkäfer (Coleoptera: Elateridae) bezeichnet, welche häufig in Agrarböden anzutreffen sind. Die meisten Drahtwurmarten sind polyphag und fressen neben Wurzeln auch abgestorbenes Pflanzenmaterial. Bestimmte Arten treten jedoch weltweit als bedeutende Schädlinge an verschiedensten Kulturpflanzen auf. Es wird angenommen, dass bestimmte Bodenparameter (z.B. Humusgehalt, Feuchte) und die Fruchtfolge die Nahrungswahl der Drahtwürmer entscheidend beeinflussen. Im Freiland konnten diese Beziehungen bis heute jedoch nicht nachgewiesen werden. Ein besseres Verständnis der Wechselwirkung zwischen diesen Faktoren und der Nahrungswahl der Drahtwürmer würde aber die Einschätzung der tatsächlichen Rolle bestimmter Drahtwurmarten erheblich erleichtern und eine Basis für die Vorhersage und Kontrolle von Drahtwurmschäden darstellen. Im vorliegenden Projekt wird erstmals die Stabile-Isotopen-Methode angewandt, um die Nahrungswahl von Elateridenlarven zu untersuchen. Dabei geben die unter Freilandbedingungen gewonnenen Isotopendaten der Drahtwürmer darüber Auskunft, von welchen Nahrungssubstraten sich diese Tiere ernähren. Zusätzliche Laborexperimente ergänzen die Befunde aus dem Freiland und helfen bei ihrer Interpretation. Um allgemeine Aussagen über die Nahrungswahl von Drahtwürmern in Mitteleuropa zu erhalten, werden verschiedenste Standorte in Österreich und Deutschland beprobt. Weiters wird das Nahrungswahlverhalten mit bestimmten Bodenparametern in Beziehung gesetzt, um zu analysieren, wie diese Parameter die Nahrungswahl der Drahtwürmer und ihr Schadpotential beeinflussen. Die Ergebnisse dieses Projektes stellen damit eine Basis für alle weiteren Schritte zur Entwicklung von Regulationsmaßnahmen bei Drahtwürmern dar.

TOC, TIC, TN and TS contents and stable isotope signatures (δ13C of TOC, δ15N, δ34S) of fine-grained saltmarsh deposits of the barrier island Spiekeroog at the southern North Sea Coast

The dataset compiles total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN) and total sulfur (TS) contents and stable isotope signatures (δ13C of TOC, δ15N, δ34S) of fine-grained deposits (clay, loam) over sandy subsoils of the saltmarsh of the barrier island Spiekeroog at the southern North Sea coast. Sampling was performed in September 2016 along three transects spanning from the high saltmarsh to the pioneer zone. At each sample point, soil samples were taken from the first 5 cm of the upper part (top samples) and from the deepest 5 cm of the lower part (bottom samples) of the fine-grained deposit. If the fine-grained deposit layer had a thickness < 10 cm, only one bulk soil sample (single samples) was taken for the depth range equal to the deposit thickness. Samples were ground to fine powder. TIC was measured on oven-dried samples coulometrically with an Analytik Jena multi EA 4000 analyzer. The total carbon (TC), TN, and TS were analyzed using a Thermo Scientific Flash EA Isolink Elemental Analyzer. The TOC contents were calculated as the difference between TC and TIC. TOC, TN, and TS contents are reported based on the original dry mass. For isotope analysis, dried and homogenized samples were weighed in tin cups and combusted in a Thermo Scientific Flash EA Isolink Elemental Analyzer, connected to a Thermo Finnigan MAT 253 gas mass spectrometer via a Thermo Conflo IV split interface. The δ13C values of TOC were measured after decalcification of the ground powders with p. a. grade HCl. The TN and δ34S analysis were carried out on a separate aliquot of sample powder. The isotope results are given in the conventional δ-notation.

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