DOI: 10.5061/dryad.v6wwpzh7t
title: Sedimentation of autochthonous labile lipids facilitates methane ebullition

description: Methane (CH₄) emissions from reservoirs contribute largely to global
 greenhouse gas budgets, with ebullition from sediments being the main
 pathway. Methanogenesis is the final step in the anaerobic microbial
 degradation of organic matter, but the specific substrates promoting this
 step still remain poorly understood. Here, we identify specific lipids in
 the organic matter from sediment traps during a one-year cycle to further
 relate them with in-situ CH₄ ebullition measurements. Phytol, short-chain
 n-alkanols, and short-chain fatty acids showed either a strong synchrony
 or a brief one-week delay to CH₄ ebullition peaks, indicating a fast
 transformation of these substrates by syntrophic microorganisms into
 precursors of methanogenesis. Phytol sedimentation was strongly coupled to
 CH₄ ebullition, highlighting the importance of this chlorophyll
 degradation substrate. Also, sedimentation of unsaturated fatty acids from
 autochthonous algae and zooplankton was synchronized with CH4 ebullition.
 Our research underlines the role of lipid structure, origin, and
 seasonality, providing key insights for predicting CH4 ebullition under
 the current increase in eutrophication.
description: # Sedimentation of autochthonous labile lipids facilitates methane
 ebullition **AUTHORS:** Andrés Martínez-García, Ignacio Peralta-Maraver,
 Miriam García-Algualcil, Eva Rodríguez-Velasco, Marta Rodrigo-Gámiz,
 Sebastian Naeher, Isabel Reche **FILES:** Contains 3 files: **1.
 code_lipids.R** - R script to replicate analyses and the figures,
 including: Figure 2: Time series showing how the Methane Index and the
 GDGT/Crenarchaeol ratio relateto methane emissions over time Figure 3:
 Specific lipids vs. methane representation, and correlation values Figure
 4: PCA of lipid profiles and methane ebullition Figure 5: Visualizing
 model terms **2. Dataset** with two different .xlsx documents 2.1.
 data.xlsx - time_series: Contains information of the sampled variables
 during the study period. **Columns**: date: date of sampling C12_OH: C-12
 n-alkanol sedimentation flux C13_OH: C-13 n-alkanol sedimentation flux
 C14_OH: C-14 n-alkanol sedimentation flux C15_OH: C-15 n-alkanol
 sedimentation flux C16_OH: C-16 n-alkanol sedimentation flux C17_OH: C-17
 n-alkanol sedimentation flux C18_OH: C-18 n-alkanol sedimentation flux
 C20_OH: C-20 n-alkanol sedimentation flux C21_OH: C-21 n-alkanol
 sedimentation flux C22_OH: C-22 n-alkanol sedimentation flux C23_OH: C-23
 n-alkanol sedimentation flux C24_OH: C-24 n-alkanol sedimentation flux
 C25_OH: C-25 n-alkanol sedimentation flux C26_OH: C-26 n-alkanol
 sedimentation flux C27_OH: C-27 n-alkanol sedimentation flux C28_OH: C-28
 n-alkanol sedimentation flux C29_OH: C-29 n-alkanol sedimentation flux
 C30_OH: C-30 n-alkanol sedimentation flux Phytol: Phytol sedimetation flux
 Cholesterol: Cholesterol sedimetation flux Cholestanol: Cholestanol
 sedimetation flux Brassicasterol: Brassicasterol sedimetation flux
 Campesterol: Campesterol sedimetation flux Campestanol: Campestanol
 sedimetation flux Stigmasterol: Stigmasterol sedimetation flux
 Stigmastanol: Stigmastanol sedimetation flux Sitosterol: Sitosterol
 sedimetation flux Sitostanol: Sitostanol sedimetation flux beta_amyrin:
 beta_amyrin sedimetation flux alpha_amyrin: alpha_amyrin sedimetation flux
 Amyrins: Amyrins sedimetation flux lupeol: lupeol sedimetation flux
 diplopterol: diplopterol sedimetation flux Sitosterol: Sitosterol
 sedimetation flux C27_sterols: summatory of sterols with 27 carbons
 C28_sterols: summatory of sterols with 28 carbons C29_sterols: summatory
 of sterols with 29 carbons C12_FA: total C12:0 fatty acid sedimentation
 flux C13_FA: total C13:0 fatty acid sedimentation flux C14_iso: C14:0
 isomer fatty acid sedimentation flux C14_0: C14:0 fatty acid sedimentation
 flux C14_FA: total C14:0 fatty acid sedimentation flux C15_iso: C15:0
 isomer fatty acid sedimentation flux C15_anteiso: C15:0 isomer fatty acid
 sedimentation flux C15_0: C15:0 fatty acid sedimentation flux C15_FA:
 total C15:0 fatty acid sedimentation flux C16_iso: C16:0 isomer fatty acid
 sedimentation flux C16_0: C16:0 fatty acid sedimentation flux C16_FA:
 total C16:0 fatty acid sedimentation flux C17_iso: C17:0 isomer fatty acid
 sedimentation flux C17_anteiso: C17:0 isomer fatty acid sedimentation flux
 C17_0: C17:0 fatty acid sedimentation flux C17_FA: total C17:0 fatty acid
 sedimentation flux C18_FA: C18:0 fatty acid sedimentation flux C20_FA:
 C20:0 fatty acid sedimentation flux C22_FA: C22:0 fatty acid sedimentation
 flux C23_FA: C23:0 fatty acid sedimentation flux C24_FA: C24:0 fatty acid
 sedimentation flux C26_FA: C26:0 fatty acid sedimentation flux C28_FA:
 C28:0 fatty acid sedimentation flux C16_1ω5: C16:1ω5 fatty acid
 sedimentation flux C16_1ω7: C16:1ω7 fatty acid sedimentation flux C16_1ω6:
 C16:1ω6 fatty acid sedimentation flux C16_1ω8: C16:1ω8 fatty acid
 sedimentation flux C17_1ω7: C17:1ω7 fatty acid sedimentation flux C18_1ω9:
 C18:1ω9 fatty acid sedimentation flux C18_1ω7: C18:1ω7 fatty acid
 sedimentation flux C18_1ω5: C18:1ω5 fatty acid sedimentation flux C18_2ω6:
 C18:2ω6 fatty acid sedimentation flux C18_1ω7: C18:2ω7 fatty acid
 sedimentation flux C20_1ω9: C20:1ω9 fatty acid sedimentation flux C20_1ω7:
 C18:1ω7 fatty acid sedimentation flux methane: methane ebullition rate
 total_FA: summatory of all measured fatty acids total_OH: summatory of all
 measured n-alkanols SCOH: summatory of all measured short chain (C12-C20)
 n-alkanols SCOH: summatory of all measured long chain (C21-C30) n-alkanols
 nitrate: water column nitrate concentration sulphate: water column
 sulphate concentration oxygen: water column oxygen concentration
 temperature: water column temperature concentration GDGT0_cren:
 GDGT0/crenarchaeol ratio MI: Methane Index TLE: total lipid extract
 concentration GDGT0: GDGT-0 sedimentation flux GDGT1: GDGT-1 sedimentation
 flux GDGT2: GDGT-2 sedimentation flux GDGT3: GDGT-3 sedimentation flux
 Cren: Crenarchaeol sedimentation flux IIIa: GDGT-IIIa sedimentation flux
 IIIb: GDGT-IIIb sedimentation flux IIIc: GDGT-IIIc sedimentation flux IIa:
 GDGT-IIa sedimentation flux IIb: GDGT-IIb sedimentation flux IIc: GDGT-IIc
 sedimentation flux Ia: GDGT-Ia sedimentation flux Ib: GDGT-Ib
 sedimentation flux Ic: GDGT-Ic sedimentation flux synchronous_FA:
 summatory of all synchonous fatty acids Lagged_FA: summatory of all 1-week
 lagged fatty acids isoGDGT: summatory of all isoprenoid fatty acids
 brGDGT: summatory of all branched fatty acids 2.2. methane.xlsx -
 Correlation between methane and lipids - for graphical representation
 **Columns**: methane: repeated methane text column: name of each lipid
 cor: correlation value for each compound with methane p: p-value for each
 compound with methane code: code to order compounds in graph 3d
 **IMPORTANT NOTE:** empty cells in dataset represent missing values