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

2021 ◽  
Author(s):  
Edgart Flores ◽  
Sebastian Cantarero ◽  
Paula Ruiz-Fernández ◽  
Nadia Dildar ◽  
Matthias Zabel ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Sediments ◽  
Polar Lipids ◽  
Labile Organic Matter ◽  
Intact Polar Lipids

scholarly journals Intact polar lipids in the hadal seabed of the Atacama Trench point to lateral sediment transport and in situ production as key sources of labile organic matter

2021 ◽  
Author(s):  
Edgart Flores ◽  
Sebastian I. Cantarero ◽  
Paula Ruiz-Fernández ◽  
Nadia Dildar ◽  
Matthias Zabel ◽  
...  
Keyword(s):  
High Pressure ◽  
Organic Matter ◽  
Low Temperature ◽  
Unsaturated Fatty Acids ◽  
Euphotic Zone ◽  
Polar Lipids ◽  
Physiological Adaptation ◽  
Labile Organic Matter ◽  
Intact Polar Lipids

Abstract. Elevated concentrations of organic matter are found in sediments of hadal trenches relative to those found in the abyssal seabed, but the origin of such biological material remains elusive. Here, we report the composition and distribution of cell membrane intact polar lipids (IPLs) in surface sediments around the deepest points of the Atacama Trench and adjacent bathyal depths to assess and constrain the sources of labile organic matter 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 labile 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 organic matter from shallower sediment. We argue that the export of the most labile lipid component of the organic matter 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 organic matter to this extreme deep-sea ecosystem, whereas they provide insights into some potential physiological adaptation of the in situ microbial community to high pressure and low temperature through lipid remodeling.

scholarly journals Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

2010 ◽  
Vol 7 (11) ◽  
pp. 3473-3489 ◽  
Author(s):  
J. Holtvoeth ◽  
H. Vogel ◽  
B. Wagner ◽  
G. A. Wolff
Keyword(s):  
Organic Matter ◽  
Lipid Biomarkers ◽  
Lake Ohrid ◽  
Labile Organic Matter ◽  
Glacial Sediments ◽  
Plant Matter ◽  
Lipid Biomarker ◽  
First Results ◽  
Near Shore

Abstract. Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event). Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats), in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.

scholarly journals Measuring rates of gross photosynthesis and net community production in cryoconite holes: a comparison of field methods

2010 ◽  
Vol 51 (56) ◽  
pp. 153-162 ◽  
Author(s):  
J. Telling ◽  
A.M. Anesio ◽  
J. Hawkings ◽  
M. Tranter ◽  
J.L. Wadham ◽  
...  
Keyword(s):  
Organic Matter ◽  
Molar Ratio ◽  
Net Community Production ◽  
Field Methods ◽  
Labile Organic Matter ◽  
Gross Photosynthesis ◽  
Ice Melt ◽  
Order Of Magnitude ◽  
Community Production

AbstractPhotosynthesis by microbes on the surfaces of glaciers and ice sheets has the potential to fix carbon, alter the albedo of ice surfaces via the production of organic matter and so enhance ice melt. It could also be important for supplying labile organic matter and nutrients to in situ and downstream ecosystems. This study compares in situ 24 hour incubation methods for measuring rates of gross photosynthesis, respiration and net community production (NCP) in cryoconite holes on three Svalbard valley glaciers. Rates of gross photosynthesis and respiration measured by the ΔCO2method were closely balanced, resulting in rates of NCP close to the detection limit (mean of –1.3 μg C g−1d–1) consistent with previous measurements in Arctic cryoconite holes. This suggests that organic matter within cryoconite holes may be derived largely from allochthonous sources. The molar ratio of ΔO2to ΔCO2in incubations gave mean respiratory and photosynthetic quotients of 0.80 ± 0.17 (1 × SD) and 1.24 ± 0.20 (1 × SD), respectively. The 14C method typically underestimated rates of gross photosynthesis (ΔCO2method) by more than one order of magnitude and measured a rate closer to NCP.

Assessment of the sources, transport and fate of sewage-derived organic matter in Port Phillip Bay, Australia, using the signature lipid coprostanol

1999 ◽  
Vol 50 (6) ◽  
pp. 547 ◽  
Author(s):  
John K. Volkman ◽  
Teresa O'Leary ◽  
Rhys Leeming ◽  
Peter D. Nichols ◽  
John K. Volkman
Keyword(s):  
Organic Matter ◽  
Surface Sediments ◽  
Sewage Treatment ◽  
Total Sterol ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Dry Weight ◽  
Labile Organic Matter ◽  
Faecal Contamination ◽  
Sewage Contamination

To evaluate the distribution of faecal material in Port Phillip Bay, surface sediments from sites throughout the bay and inflowing water courses were analysed for fatty acids and sterols. Water samples were also collected to identify possible sources of faecal contamination. Bay sediments had total fatty acid concentrations between 4 and 183 µg g–1 (dry weight) and total sterol concentrations between 0.6 and 39.2 µg g–1. Creek sediments contained more sterols, ranging from 22.8–148 µg g–1. These lipid distributions suggest that the bulk of the labile organic matter derives from marine microalgae, primarily diatoms. Coprostanol (5β-cholestan-3β-ol), a sterol often used as an indicator of faecal contamination, was also present. Concentrations ranged from <0.01–0.55 µg g–1 in surface sediments, with values over 0.25 µg g–1 and 5β-/5α-C27 stanol ratios greater than 0.4, indicative of sewage inputs. A clearer picture of distributions of sewage-derived organic matter was obtained when coprostanol was normalized to total organic matter rather than sediment dry weight. Areas showing higher coprostanol concentrations included those adjacent to the main sewage treatment plant and several low-volume drains and creeks, indicating localized problems of sewage contamination.

Chemical investigation of lake sediments and their interpretation

1965 ◽  
Vol 161 (984) ◽  
pp. 295-309 ◽  
Keyword(s):  
Organic Matter ◽  
Lake Sediments ◽  
Land Surface ◽  
Drainage Basin ◽  
Drainage System ◽  
Labile Organic Matter ◽  
Glacial Sediments ◽  
Algal Material ◽  
Lake Waters

Before any interpretation of compositional changes in a lake sediment column can be attempted, it is necessary to recognize the sources from which the sediment has been derived. Unlike bogs, whose deposits consist largely of materials synthesized in situ , lakes and particularly those of the Lake District, are greatly influenced by inflow and their sediments may derive material from a drainage basin some twenty or thirty times as large as the area of the lake itself. The glacial lake sediments consist wholly of mineral clay, often laminated, which must have been derived from the drainage basin. The post-Glacial sediments contain some 70 or 80 % of mineral material similarly derived. The remaining 20 to 30% consists of organic matter which may have originated photosynthetically either on the land surface or in the waters of the lake. The organic matter which eventually becomes buried in the sediment must have reached a state of stability towards oxidation since it must have been exposed to oxidizing conditions either in the soil or at the mud surface for many years before its final incorporation in the sediment. There is evidence from observations on Windermere and on Blelham Tarn, that the algal material produced in the lakes is very readily oxidized at the mud surface and that the oxygen consumed from the lake waters is largely used in oxidation of this comparatively labile organic matter. The major part of the organic material remaining in lake sediments is therefore likely to have been derived from stable residues produced in the soils of the drainage system . The sediment may then be regarded as an accumulation of debris derived from the land surface with minor additions from the lake biomass, though these latter additions may make important contributions to the precipitation of some elements of which phosphorus is an example. The information to be obtained from a study of lake sediments is therefore mainly concerned with events affecting the surrounding land surface rather than the lake itself, though conditions existing in the lake in former times may often be inferred from the sedimentary composition.

Characteristics and origin of intact polar lipids in soil organic matter

2020 ◽  
Vol 151 ◽  
pp. 108045
Author(s):  
Su Ding ◽  
Markus Lange ◽  
Julius Lipp ◽  
Valérie F. Schwab ◽  
Somak Chowdhury ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Polar Lipids ◽  
Intact Polar Lipids
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