Intact Polar Lipids in Surface Sediments of The Atacama Trench Point to In Situ Dominant Sources of Labile Organic Matter in the Hadal Seabed Journal Article uri icon

Overview

abstract

  • Elevated organic matter (OM) concentrations are found in hadal surface; sediments relative to the surrounding abyssal seabed. However, the; origin of the biological material remains elusive. Here, we report the; composition and distribution of cellular membrane intact polar lipids; (IPLs) extracted from surface sediments around the deepest points of the; Atacama Trench and adjacent bathyal margin to assess and constrain the; sources of labile OM in the hadal seabed. Multiscale bootstrap; resampling of IPLs’ structural diversity and abundance indicates; distinct lipid signatures in the sediments of the Atacama Trench that; are more closely related to those found in bathyal sediments than to; those previously reported for the upper ocean water column in the; region. While the overall number of unique IPL structures in hadal; sediments is limited and they contribute a small fraction of the total; IPL pool, they include a high contribution of phospholipids with mono-; and di-unsaturated fatty acids that are not associated with; photoautotrophic sources. The diversity of IPLs in hadal sediments of; the Atacama Trench suggests the presence of in situ microbial production; and biomass that resembles traits of physiological adaptation to high; pressure and low temperature, and/or the transport of labile OM from; shallower sediment. We argue that the export of the most labile lipid; component of the OM pool from the euphotic zone and the overlying oxygen; minimum zone into the hadal sediments is neglectable. Our results; contribute to the understanding of the mechanisms that control the; delivery of labile OM to this extreme deep-sea ecosystem. Furthermore,; they provide insights into some potential physiological adaptation of; the in situ microbial community to high pressure and low temperature; through lipid remodeling.

publication date

  • December 6, 2021

has restriction

  • closed

Date in CU Experts

  • December 21, 2021 5:10 AM

Full Author List

  • Flores E; Cantarero S; Ruiz-Fernández P; Dildar N; Zabel M; Ulloa O; Sepulveda J

author count

  • 7

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