Energize New Mexico
National Science Foundation
We present the identification and vertical distribution of suspended particulate lipids comprised of C, H and O which have the potential to sequester carbon from the upper ocean when associated with sinking particles. Lipids have been shown to be valuable in a host of environments to detail both the sources and processing of organic materials in the oceans. Here we present this level of information, enabled by direct-infusion, high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). We present the water column distribution of free fatty acids, tri-, di- and monoacylglycerols from the surface layer to abyssopelagic depth (4800 m) for samples that originate in the Northeast Atlantic at the Porcupine Abyssal Plain sustained observatory (PAP-SO) (49.8 Â°N, 16.58 Â°W) . Triacylglycerols (TG) with even carbon number (TG) and odd carbon number (oddTG, reflecting bacterial origin), were analysed, while free fatty acids were analysed as unsaturated (UFA), branched (BrFA) and saturated (SAFA) fatty acids. The surface productive layer (euphotic zone) was characterized with the highest incidence of compounds including lipids that are not reported in the Nature Lipidomics Gateway, especially lipids that are highly unsaturated (acyl chain unsaturation was on average 3.8 for TG, oddTG, UFA and diacylglycerols (DG)). Additionally, we observed high lipid degradation at epipelagic depths. Fatty acid markers indicate that diatoms and dinoflagellates were important contributors to the lipid pool. Depth-resolved lipid changes include decreased lipid abundance and molecular diversity together with substantial loss of unsaturation with increasing depth. The major lipid changes occur at upper mesopelagic depths. Unlike other observed lipids, the abundance of SAFA remained essentially constant across the water column whereas the number of SAFAs and their contribution to total lipids increased with depth. Thus, we demonstrate that lipid saturation affects the export of carbon from the atmosphere to the deep ocean.
Schaub, Tanner. "Free fatty acids, tri-, di- and monoacylglycerol production and depth-related cycling in the Northeast Atlantic." (2018). https://digitalrepository.unm.edu/energizenm/673