Distribution of lipid compounds in the sediments of the East Pacific Rise near 13°N and its implications for hydrothermal activity

The eruption and diffusion of hydrothermal materials will affect the surrounding sediments, and the study on the lipid in the sediments affected by hydrothermal activity is helpful to understand the influence of hydrothermal activity on sediments. In this research, N-alkanes and fatty acids in the sediments from E271 and E272 stations on the west flank of the East Pacific Rise near 13°N are analyzed by gas chromatography and mass spectrometry (GC-MS). C₁₁—C₃₅ N-alkanes, which are mainly distributed in a bimodal pattern, are detected in the sediments, in which short-chain alkanes and long-chain alkanes indicate the inputs of marine bacteria, terrestrial higher plants and materials from hydrothermal activities, respectively. Terrestrial materials are mainly from the American continent transported by wind. Furthermore, the composition and distribution of n-alkanes in the sediments suggest that the sediments of E272 station have experienced early diagenesis. 32 types of fatty acids are detected in the sediments from the stations of E271 and E272, which ranged from C₈ to C₂₄, and the total fatty acid contents of the two stations are 93.55 and 50.71～87.05 μg/g, respectively. The composition and distribution of characteristic fatty acids in the sediments exhibit the characteristics of hydrothermal input, indicating that the sediments have been affected by hydrothermal activities.