Stable carbon and hydrogen isotopic compositions of palmitic acid in surface sediment from Baffin Bay and the Labrador Sea ...

• Main Authors: Allan, Estelle, Douglas, Peter M J, de Vernal, Anne, Gélinas, Yves, Mucci, Alfonso
• Format: Dataset
• Language: English
• Published: PANGAEA 2023
• Subjects: Baffin Bay; Carbon isotopes; Hydrogen isotopes; Labrador Sea; lipid biomarkers; Palmitic acid; Event label; Site; DEPTH, sediment/rock; δ13C, organic carbon; Carbon; Carbon, organic; Carbon, inorganic, total; Nitrogen; Carbon organic/Nitrogen, molar ratio; Hexadecanoic acid, δ13C; Hexadecanoic acid, δ13C, standard deviation; δ Deuterium, palmitic acid; δ Deuterium, palmitic acid, standard deviation; Ratio; Saturated fatty acids, per unit sediment mass; Saturated fatty acids, per unit mass total organic carbon; n-fatty acid C16, per unit sediment mass; n-fatty acid C16, per unit mass total organic carbon; n-fatty acid C18, per unit sediment mass; n-fatty acid C18, per unit mass total organic carbon; n-fatty acid C161, per unit sediment mass; n-fatty acid C161, per unit mass total organic carbon; n-fatty acid C181, per unit sediment mass; n-fatty acid C181, per unit mass total organic carbon; n-fatty acid C182, per unit sediment mass; n-fatty acid C182, per unit mass total organic carbon; Carbon Preference Index; Average chain length; Dinoflagellate cyst, per unit sediment mass; Dinoflagellate cyst, phototrophic; Dinoflagellate cyst, heterotrophic; Pollen, per unit sediment mass; Spores per unit sediment mass; Palynomorpha, reworked per unit sediment mass; Sea surface salinity, summer; Sea surface salinity, winter; Sea surface salinity, annual mean; Bottom water salinity, annual mean; Sea surface temperature, summer; Sea surface temperature, winter; Sea surface temperature, annual mean; Bottom water temperature; Sea ice cover duration; Primary production of carbon per area, yearly; Baffin; Sea ice
• Online Access: https://dx.doi.org/10.1594/pangaea.960177; https://doi.pangaea.de/10.1594/PANGAEA.960177

Palmitic acid (PA) is ubiquitous in the biosphere and its hydrogen isotopic composition (δ2HPA) was proposed as a potential paleoenvironmental proxy for salinity, with δ2HPA values increasing with salinity. In this study, we analyzed 40 surface sediment samples from Baffin Bay and the Labrador Sea to examine the isotopic composition of PA in relation to local environmental variables, including salinity. In contrast to expectations, our results show a negative relationship between the δ2HPA and sea-surface salinity, raising questions about its pertinence/usefulness as a salinity proxy. Instead, our results suggest that the relative abundance of distinct organisms that employ different metabolisms is key in determining the hydrogen isotopic fractionations in PA. Whereas we show that PA is mostly produced through photoautotrophic metabolisms by diatoms and dinoflagellates, varying contributions from heterotrophic metabolisms may obscure the stable isotope composition of PA. Surprisingly, we found no correlation ...