scholarly journals A potential suite of climate markers of long-chain n-alkanes and alkenones preserved in the top sediments from the Pacific sector of the Southern Ocean

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Chen ◽  
Xiaodong Liu ◽  
Da-Cheng Lin ◽  
Jianjun Wang ◽  
Liqi Chen ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Organic Compounds ◽  
Higher Plant ◽  
New Information ◽  
The Pacific ◽  
Study Results ◽  
History Of ◽  
Chemoautotrophic Bacteria ◽  
Plant Waxes ◽  
Long Chain

AbstractInvestigating organic compounds in marine sediments can potentially unlock a wealth of new information in these climate archives. Here, we present pilot study results of organic geochemical features of long-chain n-alkanes and alkenones and individual carbon isotope ratios of long-chain n-alkanes from a newly collected, approximately 8 m long, located in the far reaches of the Pacific sector of the Southern Ocean. We analyzed a suite of organic compounds in the core. The results show abundant long-chain n-alkanes (C29–C35) with predominant odd-over-even carbon preference, suggesting an origin of terrestrial higher plant waxes via long-range transport of dust, possibly from Australia and New Zealand. The δ13C values of the C31n-alkane range from −29.4 to −24.8‰, in which the higher δ13C values suggest more contributions from C4 plant waxes. In the analysis, we found that the mid-chain n-alkanes (C23–C25) have a small odd-over-even carbon preference, indicating that they were derived from marine non-diatom pelagic phytoplankton and microalgae and terrestrial sources. Furthermore, the C26 and C28 with lower δ13C values (~−34‰) indicate an origin from marine chemoautotrophic bacteria. We found that the abundances of tetra-unsaturated alkenones (C37:4) in this Southern Ocean sediment core ranges from 11 to 37%, perhaps a marker of low sea surface temperature (SST). The results of this study strongly indicate that the δ13C values of long-chain n-alkanes and $$ {U}_{37}^{\mathrm{k}} $$ U 37 k index are potentially useful to reconstruct the detailed history of C3/C4 plants and SST change in the higher latitudes of the Southern Ocean.

scholarly journals A potential suite of climate markers of long-chain n-alkanes and alkenones preserved in the top sediments from the Pacific sector of the Southern Ocean

2021 ◽  
Author(s):  
Xin Chen ◽  
Xiaodong Liu ◽  
Da-Cheng Lin ◽  
Jianjun Wang ◽  
Liqi Chen ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Organic Compounds ◽  
Higher Plant ◽  
Δ13c Values ◽  
New Information ◽  
The Pacific ◽  
Study Results ◽  
Chemoautotrophic Bacteria ◽  
Plant Waxes ◽  
Long Chain

Abstract Investigating organic compounds in marine sediments can potentially unlock a wealth of new information in these climate archives. Here we present pilot study results of organic geochemical features of long-chain n-alkanes and alkenones and individual carbon isotope ratios of long-chain n-alkanes from a newly collected, approximately 8-meter long, located in the far reaches of the Pacific sector of the Southern Ocean. We analyzed a suite of organic compounds in the core. The results show abundant long-chain n-alkanes (C29-C35) with predominant odd-over-even carbon preference, suggesting an origin of terrestrial higher plant waxes via long-range transport of dust, possibly from Australia and New Zealand. The δ13C values of the C31 n-alkane range from -29.4 to -24.8‰, in which the higher δ13C values suggest more contributions from C4 plant waxes. In the analysis, we found that the mid-chain n-alkanes (C23-C25) have a small odd-over-even carbon preference, indicating that they were derived from marine non-diatom pelagic phytoplankton and microalgae and terrestrial sources. Furthermore, the C26 and C28 with lower δ13C values (~ -34‰) indicate an origin from marine chemoautotrophic bacteria. We found that the abundances of tetra-unsaturated alkenones (C37:4) in this Southern Ocean sediment core ranges from 11-37%, perhaps a marker of low sea surface temperature (SST). The results of this study strongly indicate that the δ13C values of long-chain n-alkanes and index are potentially useful to reconstruct the detailed history of C3/C4 plants and SST change in the higher latitudes of the Southern Ocean.

scholarly journals A Potential Suite of Climate Markers of Long-Chain n-Alkanes and Alkenones Preserved in the top Sediments from the Pacific Sector of the Southern Ocean

2020 ◽  
Author(s):  
Xin Chen ◽  
Xiaodong Liu ◽  
Da-Cheng Lin ◽  
Jianjun Wang ◽  
Liqi Chen ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Organic Compounds ◽  
Sediment Core ◽  
Higher Plant ◽  
New Information ◽  
The Pacific ◽  
Study Results ◽  
History Of ◽  
Chemoautotrophic Bacteria ◽  
Long Chain

Abstract Investigation of organic compounds in marine sediments can potentially unlock a wealth of new information in these overlooked climate archives. Here we present pilot study results of organic geochemical features of long-chain n-alkanes and alkenones and individual carbon isotope ratios of long-chain n-alkanes from a newly collected, approximately 8-meter long, Pleistocene age sediment core, located in the far reaches of the Pacific sector of the Southern Ocean. We initially analyzed a suite of organic compounds in the core, and the results show abundant long-chain n-alkanes (C29-C35) with predominant odd-over-even carbon preference, which suggests an origin of terrestrial higher plant waxes via long range transport of dust, possibly from Australia and New Zealand. The δ13C values of the C31 n-alkane range from -29.4 to -24.8‰, in which the higher δ13C values suggest more contributions from C4 plants waxes. In the analysis, we found that the mid-chain n-alkanes (C23-C25) have small odd-over-even carbon preference, suggesting that they were derived from marine non-diatom pelagic phytoplankton and microalgae, and terrestrial sources. Furthermore, the C26 and C28 with lower δ13C values (~ -34‰) indicate an origin from marine chemoautotrophic bacteria. We found that the abundances of tetra-unsaturated alkenones (C37:4) in this Southern Ocean sediment core ranges from 11-37%, perhaps a marker of low sea surface temperature (SST). The results of this study strongly indicate that the δ13C values of long-chain n-alkanes and index are potentially useful to reconstruct detailed history of C3/C4 plants and SST change in the higher latitudes of the Southern Ocean.

scholarly journals Lipid abundance and composition of a humic Oxisol as a function of land use

2011 ◽  
Vol 68 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Cristiane Pereira de Assis ◽  
Francisco Javier González-Vila ◽  
Ivo Jucksch ◽  
Jose Antonio González-Pérez ◽  
Júlio César Lima Neves ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Lipid Composition ◽  
Gas Chromatography Mass Spectrometry ◽  
Native Forest ◽  
Higher Plant ◽  
Alkanoic Acids ◽  
Plant Waxes ◽  
Long Chain

Soil organic matter of a humic Oxisol has been characterized by analyzing litter and soil lipid composition under vegetal covers (coffee, pasture and fragment of native forest). Soil and litter samples were collected from each site at two depths (0-10 and 60-100 cm). Lipid composition was determined by gas chromatography-mass spectrometry (CG-MS). In the solvent extracts of the soil lipids, even-numbered n-alkanoic acids in the range of C16-C32 indicate a soil organic matter input from higher plant waxes. The major compound classes in both the soil and the litter included saturated n-alkanoic acids, with average values in the total spectrum of 58 and 53%, respectively Clear differences in lipid composition were found between the topsoil and subsurface. Long chain alkylic compounds (alkanoic acids and alkanes) accumulated preferably at depths of 60-100 cm. On the surface, the soil from natural vegetation had a total lipid value higher than those cultivated soils, and showed a predominance of unsaturated alkanoic acids at 60-100 cm. Preservation of alkylic moieties with depth was observed under forest and pasture, indicating that these systems of land use are prone to lipid accumulation. Lipids, especially the long-chain (> C20) ones, may be important with regard to C stabilization and humification processes in subsoil of humic Oxisols, highlighting the importance of lipids compounds in the bulk structure of organic matter these soils.

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

Efficacy of intrauterine administration of autologous peripheral blood mononuclear cells prior to embryo transfer in patients with recurrent implantation failures in assisted reproductive technology programmes

GYNECOLOGY ◽  
2018 ◽  
Vol 20 (2) ◽  
pp. 28-33
Author(s):  
T S Amyan ◽  
S G Perminova ◽  
L V Krechetova ◽  
V V Vtorushina
Keyword(s):  
Embryo Transfer ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Peripheral Blood Mononuclear ◽  
Study Objective ◽  
Study Results ◽  
Blood Mononuclear Cells ◽  
History Of ◽  
Group 2

Study objective. To evaluate the efficacy of intrauterine administration of autologous peripheral blood mononuclear cells (PBMC) prior to embryo transfer in patients with recurrent implantation failures in IVF program. Materials and methods. The study enrolled 129 patients with recurrent implantation failures in an IVF programme. Group 1 - 42 patients who had intrauterine administration of autologous PBMC activated with hCG (Pregnyl 500 IU). Group 2 - 42 patients who had intrauterine administration of autologous PBMC without hCG activation. Group 3 (placebo) - 45 patients who had intrauterine administration of saline. Study results. In the hCG-activated PBMC group, the rates of positive blood hCG tests, implantation, and clinical pregnancy were significantly higher than the respective rates in the non-activated PBMC group and in the placebo group, both in a stimulated cycle and in an FET cycle (р≤0.05). Conclusion. Intrauterine administration of autologous PBMC prior to embryo transfer in an IVF/ICSI programme increases the efficacy of IVF program in patients with a history of recurrent implantation failures.

A Short history of the post-graduate surgical training in Fiji - where to from here?

2018 ◽  
Vol 21 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Jitoko Kelepi Cama ◽  
Sonal Singh Nagra
Keyword(s):  
Surgical Training ◽  
Training Programme ◽  
Post Graduate ◽  
School Of Medicine ◽  
Postgraduate Training Programme ◽  
The Pacific ◽  
National University ◽  
History Of ◽  
Training Of Surgeons ◽  
Pacific Island Nations

Post-graduate surgical training at the Fiji National University (FNU), previously known as the Fiji School of Medicine) has recently been updated by incorporating elements from the Royal Australasian College of Surgeons (RACS) training curriculum. The revised curriculum maintains strong contextual relevance to the needs and pathologies of the Pacific Island nations.  This paper outlines why the FNU surgical postgraduate training programme should be applauded as a successful programme in the training of surgeons for the region.

Oceans and Landless Farms: Linking Southern and Northern Shadow Places of Industrial Livestock (1954–1975)

2020 ◽  
Author(s):  
Floor Haalboom
Keyword(s):  
Animal Feed ◽  
Marine Ecosystem ◽  
Global South ◽  
Humboldt Current ◽  
The Public ◽  
The Pacific ◽  
Production And Consumption ◽  
Boom And Bust ◽  
History Of ◽  
Global North

This article argues for more extensive attention by environmental historians to the role of agriculture and animals in twentieth-century industrialisation and globalisation. To contribute to this aim, this article focuses on the animal feed that enabled the rise of ‘factory farming’ and its ‘shadow places’, by analysing the history of fishmeal. The article links the story of feeding fish to pigs and chickens in one country in the global north (the Netherlands), to that of fishmeal producing countries in the global south (Peru, Chile and Angola in particular) from 1954 to 1975. Analysis of new source material about fishmeal consumption from this period shows that it saw a shift to fishmeal production in the global south rather than the global north, and a boom and bust in the global supply of fishmeal in general and its use in Dutch pigs and poultry farms in particular. Moreover, in different ways, the ocean, and production and consumption places of fishmeal functioned as shadow places of this commodity. The public health, ecological and social impacts of fishmeal – which were a consequence of its cheapness as a feed ingredient – were largely invisible on the other side of the world, until changes in the marine ecosystem of the Pacific Humboldt Current and the large fishmeal crisis of 1972–1973 suddenly changed this.

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