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Plant wax composition of sediment core ROT21 from the Rotsee, Switzerland

This dataset contains compound-specific hydrogen (δ2H) and carbon (δ13C) isotope compositions and concentrations of long-chain n-alkanes and fatty acids (n-alkanoic acids) from the ROT21 sediment record of Rotsee, Central Switzerland (47°04′10″N, 8°18′48″E, 419 m a.s.l.). Sediment cores were retrieved in October 2021 using a UWITEC gravity corer, and the dataset spans the past ~13,000 years based on 19 radiocarbon dates (terrestrial and aquatic macrofossils) integrated with 210Pb and 137Cs profiles (see De Jonge et al., 2025). Laboratory analyses were conducted between February 2023 and November 2024 at the University of Basel. Sediment samples (~2–5 g) were sub-sampled, freeze-dried, spiked with internal standards (n-C19-alkanoic acid, n-C36-alkane, 2-octadecanone, and n-C21-alkanol), and extracted with dichloromethane/methanol (9:1, v/v) using an Accelerated Solvent Extractor (Dionex ASE 350, Thermo Fisher Scientific). Following saponification, neutral fractions were separated via silica gel chromatography, and fatty acids were converted to fatty acid methyl esters (FAMEs). Both n-alkanes and FAMEs were further purified to isolate saturated compounds using AgNO3-impregnated silica gel columns, then analyzed and quantified by gas chromatography with flame ionization detection (GC-FID). Peak areas were normalized to recovery standards to account for potential losses during sample handling, and compounds were identified by comparison with external standards. Compound-specific δ2H and δ13C values were determined by gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and normalized to the VSMOW-SLAP (δ2H) and VPDB (δ13C) scales. Analytical precision was ±3-5 ‰ for δ2H and ±0.2–0.3 ‰ for δ13C. The dataset was generated to reconstruct past hydroclimate and vegetation dynamics in Central Europe using plant wax δ2H records. Full methodological details are provided in the study: Central Europe hydroclimate since the Younger Dryas inferred from vegetation-corrected sedimentary plant wax δ2H values (Santos et al., 2026).

Concentrations and loadings of fatty acids in surface sediments of Helgoland Mud Area in the North Sea

Surface sediment were extracted 4 times by ultrasonication with dichloromethane: methanol (9:1, v/v) for 15 min for FAs and alkanes. For quantification of FAs and alkanes, known amounts of 19-methylarachidic acid and squalane were added as internal standards prior to extraction. Supernatants from each extraction were obtained by centrifugation and combined. The total lipid extracts were concentrated and evaporated under a nitrogen stream. The total lipid extracts were saponified for 2 h at 80 °C with 1 mL of KOH (0.1 M) in methanol: H2O (9:1, v/v). After saponification, the neutral fractions were liquid-liquid extracted with n-hexane and alkanes were eluted from the neutral fractions by silica gel column chromatography with n-hexane. The remaining KOH solution was acidified to pH 1, from which FA were liquid-liquid extracted into dichloromethane. The extracted and dried FAs were converted to methyl ester derivatives (FAMEs) in methanol: HCl (95:5, v/v) at 60 °C for 12 h. After methylation, the FAME fraction was further purified by silica gel column chromatography using dichloromethane: hexane (2:1, v/v) to remove residual polar compounds. FAMEs and alkanes were analyzed on a 7890A gas chromatograph (GC) equipped with a DB-5MS fused silica capillary column (60 m, 250 µm, 0.25 µm) and a flame ionization detector (FID). Peak areas were determined by integrating the respective peaks and concentrations were calculated against the internal standards. FAME contents were subsequently corrected for the derivative methyl carbon to determine FA contents. FAs and alkanes were normalized to OC content.

Geochemical properties in surface sediments of the Helgoland Mud Area and surrounding sandy areas taken during HEINCKE cruise HE595 in the North Sea

In March 2022, 56 surface sediments were collected from the Helgoland Mud Area and surrounding sandy areas in the North Sea. These surface sediments were analyzed for grain size, organic carbon (OC) content, total nitrogen content (TN), stable carbon isotope of OC, and abundances of source-specific alkanes and fatty acids, in aim to determine and quantify composition and sources of OC, to understand the degradation and sequestration of marine and terrestrial OC in sediments, and to estimate the burial fluxes and burial efficiencies of marine and terrestrial OC in the Helgoland Mud Area. Detailed dataset interpretation can be found in Wei et al. (2024, in preparation).

Fatty acid contents of the copepod Temora longicornis

Elemental, biochemical, and fatty acid contents for the copepod Temora longicornis (and its diets) fed under laboratory conditions with different nutrient regimes

The two experiments for which data is presented in this record were conducted in the context of RMFS' PhD work. The objective of the experiments was to quantify and qualify the effects of diet quality, herein manipulated in terms of different species (the diatom Conticribra weissflogii and the dinoflagellate Oxyrrhis marina) grown under different nutrient regimes (nutrient replete and Nitrogen-depleted), on the fatty acid (FA) assimilation and turnover of the copepod Temora longicornis. Experiments used field-collected copepods; sampling for experiments I and II took place on May 17th and 30th, 2016, respectively, with a 500 µm mesh-size CalCOFI net which was towed horizontally for 15 minutes at 5 m depth off the German island of Helgoland (54o11'N, 07o54'E), in the southern North Sea. Samples were immediately taken to the laboratory, where intact and active adult females were sorted under an Olympus SZX16 stereoscopic microscope. A total of 1260 females were sorted for each date, 1080 for the feeding experiment and 180 for the determination of in situ elemental and biochemical compositions. This study was conducted concomitantly with that from Franco-Santos et al. (2018). The feeding experiment was initiated after sorting, and lasted for five days. Females were distributed between triplicate 3L plastic beakers (75 females L-1), which were fitted with a 300 µm meshed-bottom cylinder, and kept in a dark, temperature-controlled room (10 ± 0.3oC, a temperature similar to that recorded in the surface water during sampling). Batch cultures of C. weissflogii were started on a daily basis (prior to starting the experiment) for five consecutive days; a stock solution was diluted with fresh f/2 medium (with and without nitrate additions, modified from Guillard, 1975), which contained 13C-enriched sodium bicarbonate (NaH13CO3, 4 mg L-1), and was grown for five days before being used to feed copepods (details in Franco-Santos et al., 2018). The same protocol was followed to culture the cryptophycean Rhodomonas salina, but bicarbonate was added to a concentration of 12 mg L-1. The algae were then used to feed the cultures of O. marina and, thus, create its different nutrient treatments. The dinoflagellate batches were cultured with the same protocol as the diatoms, except that the stock solution was diluted on a daily basis with labelled food (i.e., R. salina) rather than once at the start of the culture with isotopically-enriched medium. Cryptophycean cell quantities given to dinoflagellates were adjusted so that the former was depleted from the cultures on day 5. Diatom and dinoflagellate diets were provided for copepods ad libitum (> 350 µg C L-1; 8 and 2 * 103 cells mL-1, respectively) on a daily basis for five days. Cell density in the cultures was determined with a BD Accuri C6 Flow Cytometer. Beakers were gently stirred three times a day in order to resuspend dietary cells. Immediately before feeding copepods, a partial (approx. 65%) water exchange was conducted, which removed most of the food from the previous day. Copepods were sampled on days 1 (in situ composition, t0h), 3 (t48h), and 6 (t120h) of the experiment. Females were pooled into 10 and 50 individuals per replicate for elemental (body carbon (C) and nitrogen (N) contents and molar C:N ratio) and biochemical (total FA content and profile, and FA-specific content and 13C isotopic signal) analyses. Sampled copepods were gently washed in distilled water, then placed into pre-weighed tin capsules (5x9 mm, IVA Analysentechnik) or pre-combusted lipid vials (for elemental and FA analyses, respectively). Cultures were sampled daily during the experiment (after food was provided to copepods) for determination of cell elemental (C and N contents and molar C:N ratio) and biochemical (total FA content and profile, and FA-specific content and 13C isotopic enrichment) compositions. Subsamples of 5.2 and 0.4 *106 cells (for diatoms and dinoflagellates, respectively) were filtered through pre-combusted (500oC for 24h) Whatman GF/F filters (0.7 µm pore size, 25 mm diameter). Tin capsules and filters with samples for elemental analysis were dried at 60oC for 48 h; filters were folded inside tin foil, and both capsules and foil were stored in a desiccator until analysis. Filters with samples for FA analyses were placed into pre-combusted lipid vials, and vails containing both copepods and filters were stored at -80oC until analyses. The dry mass (DM) and C and N contents of samples were obtained as per Franco Santos et al. (2018). Lipid extraction (modified after Folch et al., 1957) and subsequent fatty acid methyl ester (FAME) quantification were performed as described in Franco-Santos et al. (2019) (and references therein). Temora longicornis does not have significant energy reserves and exhibits triacylglycerols (TAGs) as its primary neutral lipids (Fraser et al., 1989; Peters et al., 2013). Lipid classes were not separated in this study, and it was assumed that FAMEs were composed of TAGs. The FA-specific 13C isotopic composition of FAMEs was measured according to Boissonnot et al. (2016). Lipid C assimilation and turnover were calculated according to the equations used by Boissonnot et al. (2016) and Franco-Santos et al. (2019). Lipid C assimilation efficiency (AE), the percentage of (isotopically-enriched) dietary content ingested by copepods that was assimilated into FAs, was also calculated for (a) TFA, (b) saturation-specific sums of FAs (saturated, monounsaturated, and polyunsaturated FAs), and (c) each individual FA that was both available from the diet and assimilated by copepods (> 1% TFA in copepods). All the equations necessary for these calculations are described in the data sets contained in this bundled publication.

forest_soil_fauna_densities_grouplevel_2008

<p>Original data comes from a project which takes or took place as part of the DFG priority program "Exploratories for large-scale and long-term functional biodiversity research". The data is stored together with descriptive metadata, in combination called a dataset, in the project repository (https://www.bexis.uni-jena.de). Species information was extracted from that original dataset. The second paragraph is part of the metadata of the original dataset.</p> <p>Changes in soil food web structure of the decomposer system with land use intensity in forest systems</p>

Elemental and biochemical contents of the diets of the copepod Temora longicornis

Elemental and biochemical contents of the copepod Temora longicornis

Fatty acid contents of the diets of the copepod Temora longicornis

Compilation of fatty acid composition of marine biota from the central and Northeast Atlantic, and the Mediterranean Sea

Fatty acid (FA) composition has increasingly been used to estimate the dietary preference of marine organisms. Specific fatty acids and fatty acid ratios serve as trophic markers (FATM) and have the potential to provide insights on the long-term dietary preference of organisms. FATM have been applied for this purpose on various zooplankton, fish and up to whales. We aim to build up a database of new and published data on fatty acid content of mesopelagic fish and their predators from the central and Northeast Atlantic, and the Mediterranean Sea, to use in FATM food web studies, investigating the importance of mesopelagic organisms as predators and prey in the marine ecosystem. Here we compiled FA content (i.e., the proportion of each FA measured in sampled tissues or in the whole body of organisms in relation to total FAs analysed) of 36 fish species or genera, 15 seabirds, five marine mammals, two cephalopods, one turtle, one jelly fish, and one shark. For each record, we included all FAs with values above 0.1% of total FAs and report the percentage values as provided in the original data source. Each data record is associated with information on the sampling location, geographic coordinates, month and year of sample collection, method of sample collection, taxonomic ranks (phylum, class, order, family), number and size (or size range) of sampled organisms, as well as the reference and DOI of the original data source, for further details on the samples analysed and/or the analytical techniques used.

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