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Abstract:
This dataset compiles Fatty Acid composition (relative proportions) of 4-day old Calanus hyperboreus nauplii from mothers collected in the Northern Barents Sea.
Gravid Calanus hyperboreus females were collected from the Northern Barents Sea during the Q1 Nansen Legacy Seasonal Cruise in March 2021. After hatching, 4-day old Calanus hyperboreus nauplii were used for a short-term incubation assay (24h), exposing the nauplii to acidification (pH 8.01 and 7.50) and warming (0°C and 3°C), both individually and in combination. Nauplii larvae were added to each replicate at a density of ~0.6 larvae mL-1. The bottles were kept in the dark in incubators at the target temperature for 24 hours. After the incubation, all larvae from each treatment were extracted and checked for survival, and the remaining individuals were stored in Eppendorf tubes, freeze-dried, and kept at -80°C for lipid content analysis.
Quality
The lipid content and fatty acid compositions of the copepod nauplii obtained from the incubation assays were analysed at the Alfred Wegener Institute in Bremerhaven, Germany. To acquire sufficient sample material for the analysis, between 100 to 148 individual larvae were pooled per sample. Triplicate samples (except for Treatment 3, which had duplicates) were analysed for each treatment. Before lipid extraction, the samples were freeze-dried for 24 h at -80 °C and then mechanically homogenized using a Potter-Elvehjem homogenizer. Total lipids were extracted by using a modified protocol from Folch et al., (1957), with dichloromethane/methanol (2:1, v/v), followed by cleaning with 0.88% potassium chloride solution. The extracted lipids were then transformed into fatty acid methyl esters (FAMEs) and free fatty alcohols derived from wax esters by transesterification in methanol containing 3% concentrated sulfuric acid, at 80 °C for 4 h. The FAMEs and alcohols were separated via an Agilent 6890N Network gas chromatograph (Agilent Technologies, USA) with a DB-FFAP capillary column (30 m, 0.25 mm I.D., 0.25 µm film thickness), equipped with a flame-ionization detector using a temperature program (160 to 240 °C). The samples were injected at 160 °C with helium as the carrier gas. The FAMEs were identified using standard mixtures, and the total lipid content was quantified as the sum of FAs and fatty alcohols using an internal standard (23:0) that was added prior to lipid extraction. The fatty acids are expressed in the nomenclature A:Bn-X, where A represents the number of carbon atoms, B the amount of double bonds, and X is the position of the first double bond starting from the methyl end of the carbon chain. The proportions of individual FAs are expressed as mass percentages of the total FA content.