Traces of marine nematodes from 470 million years old Early Ordovician rocks in China

Nematology ◽  
2013 ◽  
Vol 15 (5) ◽  
pp. 567-574 ◽  
Author(s):  
Andrzej Baliński ◽  
Yuanlin Sun ◽  
Jerzy Dzik
Keyword(s):  
Organic Matter ◽  
Microbial Mats ◽  
Middle Part ◽  
Early Cambrian ◽  
Marine Nematodes ◽  
Low Oxygen ◽  
Early Ordovician ◽  
Agricultural Revolution ◽  
Mode Of Life ◽  
Shallow Seas

Cylindrical, mostly horizontal, burrows of 20-60 μm diam. and sinusoidal course, found in the middle part of the Early Ordovician (early Floian) Fenxiang Formation in the Hubei Province of China, represent the oldest record of activity by marine nematodes, preceding known nematode body fossils by 70 million years. The burrows are filled with secondarily oxidised pyrite framboids and clay mineral flakes, indicating low oxygen content in the mud and proving that the animals lined their burrows with organic matter, being bacteriovores and mud-eaters. The marine bottom environment enabling such a mode of life originated no earlier than the mid Early Cambrian (approximately 535 million years ago) owing to peristaltic bioturbation, mostly by nemathelminthans of priapulid affinities. Before the so-called ‘Agricultural Revolution’, the bottoms of shallow seas were covered with microbial mats preventing within-sediment animal life. This event imposes the lower time limit on the possible date of origin of nematodes.

Early Ordovician alkali-ultramafic Zhilandy complex (Central Kazakhstan): structure and age of formation

2019 ◽  
Vol 484 (1) ◽  
pp. 61-65
Author(s):  
R. M. Antonuk ◽  
A. A. Tretyakov ◽  
K. E. Degtyarev ◽  
A. B. Kotov
Keyword(s):  
Complex Formation ◽  
Central Asian Orogenic Belt ◽  
Early Cambrian ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Central Asian ◽  
Geochronological Study ◽  
Three Stages ◽  
Late Neoproterozoic ◽  
Quartz Monzodiorites

U–Pb geochronological study of amphibole-bearing quartz monzodiorites of the alkali-ultramafic Zhilandy complex in Central Kazakhstan, whose formation is deduced at the Early Ordovician era (479 ± 3 Ma). The obtained data indicate three stages of intra-plate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic stage of alkali syenites of the Karsakpay complex intrusion, Early Cambrian stage of ultramafic-gabbroid plutons of the Ulutau complex formation, and Late Cambrian–Early Ordovician stage of formation of the Zhilandy complex and Krasnomay complex intrusions.

scholarly journals Speciation of organosulfur compounds in carbonaceous chondrites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Zherebker ◽  
Yury Kostyukevich ◽  
Dmitry S. Volkov ◽  
Ratibor G. Chumakov ◽  
Lukas Friederici ◽  
...  
Keyword(s):  
Organic Matter ◽  
Analytical Techniques ◽  
Ion Cyclotron Resonance ◽  
Organosulfur Compounds ◽  
Low Oxygen ◽  
Fticr Ms ◽  
Insoluble Organic Matter ◽  
Composition And Structure ◽  
Extractable Fraction ◽  
The Individual

AbstractDespite broad application of different analytical techniques for studies on organic matter of chondrite meteorites, information about composition and structure of individual compounds is still very limited due to extreme molecular diversity of extraterrestrial organic matter. Here we present the first application of isotopic exchange assisted Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) for analysis of alkali extractable fraction of insoluble organic matter (IOM) of the Murchison and Allende meteorites. This allowed us to determine the individual S-containing ions with different types of sulfur atoms in IOM. Thiols, thiophenes, sulfoxides, sulfonyls and sulfonates were identified in both samples but with different proportions, which contribution corroborated with the hydrothermal and thermal history of the meteorites. The results were supported by XPS and thermogravimetric analysis coupled to FTICR MS. The latter was applied for the first time for analysis of chondritic IOM. To emphasize the peculiar extraterrestrial origin of IOM we have compared it with coal kerogen, which is characterized by the comparable complexity of molecular composition but its aromatic nature and low oxygen content can be ascribed almost exclusively to degradation of biomacromolecules.

scholarly journals EXAMINING THE PROCESS OF DECOMPOSITION AND CARBON CYCLING IN 'FADAMA' COASTAL WETLANDS: A CASE STUDY OF HEAPING WETLANDS ECOSYSTEM

2020 ◽  
Vol 4 (3) ◽  
pp. 10-16
Author(s):  
George Dasat Shwamyil ◽  
G. Danjuma ◽  
E. S. Chundusu
Keyword(s):  
Organic Matter ◽  
Ecosystem Services ◽  
Carbon Cycling ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Wetland Soil ◽  
Low Oxygen ◽  
Decomposition Of Organic Matter ◽  
Plateau State

Wetlands provide several ecosystem services including carbon capture and storage, water filtration, nutrient cycling, and support agriculture among others. The biogeochemical process and decomposition parameters in ‘Fadama' wetland soils comprising of Gada biyu, Pwomol and Kpang referred to as sites A, B, and C respectively all of Heipang District in Barkin Ladi, Plateau State was investigated using standard operating procedures (SOP). Results of investigations revealed that soils from Kpang had slightly higher water content (34.52%) than those from Pwomol (33.48%) and Gada biyu (32.03%). While soils from Gada biyu had the highest solid organic matter (SOM) (10.79%) followed by Pwomol (8.15%) as Kpang had the least (7.85%). Gada biyu soils had the lowest Phenol oxidases activity (1536.56 nmol dicq g-1 h-1) while those from Pwomol (5340.44 nmol dicq g-1 h-1) was highest. All sites had similar concentrations of soil phenolics (76.58 µg g-1, 79.98µg g-1, and 83.25µg g-1). The activity of hydrolyses (β-glucosidase) in Gada biyu soil (2.93 nmol g-1 min-1) was lower than those from Pwomol (6.13 nmol g-1 min-1). These parameters indicate the level of biogeochemical processes in the soil at each site. Gada biyu had the highest rate of CH4 (0.84 ug g-1h-1) flux. Decomposition of organic matter, carbon cycling and greenhouse gas storage in wetland soil, is due to the anoxic condition comprising of low oxygen availability, cool temperatures, anaerobic conditions, reduced microbial activity, and the quality of organic matter substrates in such soils.  Anthropogenic disturbances affecting wetlands must be discouraged to promote vital ecosystem services.

Chapter 14 Cambrian-Ordovician history

1997 ◽  
Vol 17 (1) ◽  
pp. 257-271 ◽  
Author(s):  
W. Brian Harland
Keyword(s):  
Late Ordovician ◽  
Early Cambrian ◽  
The South ◽  
Thermal Event ◽  
Early Ordovician

Cambrian-Ordovician history is well documented in Svalbard with late Early Cambrian faunas and a range of Ordovician faunas to provide a basis for correlation. Not so extensive as Vendian, the rocks crop out in four areas: (i) only slightly deformed strata in the youngest Hecla Hoek (Oslobreen) Group in northeastern Svalbard yield especially rich Early to Mid-Ordovician faunas, (ii) The Hornsundian Geosyncline in south Spitsbergen with more variable facies and tectonic complications also exhibits Early Cambrian and Canadian strata, (iii) The Bjornoya succession reveals a marked hiatus between Vendian and Early and Mid-Ordovician strata, (iv) In western Svalbard the lack of Cambrian and Early Ordovician strata marks a distinct Mid Ordovician tectono-thermal event to be followed by ?Late Ordovician and Early Silurian strata. Indeed the above four areas correspond to distinct terranes which, having different affinities especially with areas in Greenland, give evidence of relatively distant areas and environments of formation. Evidence of Cambro-Ordovician volcanism is not recorded.Figure 14.1 lists the successions in the four areas mentioned according to the classification of rock units as abstracted from chapters 6, 7, 8, 9, 10 and 11, where their regional settings may be found. The outcrops are plotted on Fig. 14.2. The northeastern Svalbard strata are separated by Hinlopenstretet. This waterway divides Ny Friesland and Olav V Land in Spitsbergen from northwestern Nordaustlandet and occupies a syncline, but the successions although differently named are essentially continuous. In southern Spitsbergen the fjord Hornsund separates the successions to the south in Sorkapp Land

scholarly journals Tracking Organomineralization Processes from Living Microbial Mats to Fossil Microbialites

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 605 ◽  
Author(s):  
Inès Eymard ◽  
María Alvarez ◽  
Andrés Bilmes ◽  
Crisogono Vasconcelos ◽  
Daniel Ariztegui
Keyword(s):  
Organic Matter ◽  
South America ◽  
Fossil Record ◽  
Microbial Mats ◽  
High Density ◽  
Rich Phase ◽  
Physicochemical Processes ◽  
Carbonate Matrix ◽  
Photosynthetic Microorganisms ◽  
Mixed Carbonate

Geneses of microbialites and, more precisely, lithification of microbial mats have been studied in different settings to improve the recognition of biogenicity in the fossil record. Living microbial mats and fossil microbialites associated with older paleoshorelines have been studied in the continental Maquinchao Basin in southernmost South America. Here, we investigate carbonate crusts from a former pond where active mineralizing microbial mats have been previously studied. Petrographic observations revealed the presence of abundant erect and nonerect microfilaments and molds with diameters varying from 6 to 8 micrometers. Additionally, smaller pores and organic matter (OM) remains have been identified in areas containing less filaments and being dominated by carbonate. A Mg, Al and Si-rich phase has also been identified in the carbonate matrix associated with the dominant micritic calcite. Moreover, mineralized sheaths contain mixed carbonate (calcite) with Mg, Al and Si, where the latter elements are associated with authigenic clays. The presence of mineralized sheaths further attests to biologically induced processes during the uptake of CO2 by photosynthetic microorganisms. Additionally, the high density of the micritic phase supports the subsequent mineralization by nonphotosynthetic microorganisms and/or physicochemical processes, such as evaporation. Since the micritic filament microstructure of these recent crusts is very similar to that observed in fossil microbialites, they can be used to bridge the gap between living mats and fossil buildups.

scholarly journals Fungi and viruses as important players in microbial mats

2020 ◽  
Vol 96 (11) ◽  
Author(s):  
Cátia Carreira ◽  
Christian Lønborg ◽  
Michael Kühl ◽  
Ana I Lillebø ◽  
Ruth-Anne Sandaa ◽  
...  
Keyword(s):  
Organic Matter ◽  
Aquatic Ecosystems ◽  
Microbial Mats ◽  
Freshwater Ecosystems ◽  
Food Web Structure ◽  
Element Cycling ◽  
Functional Roles ◽  
Web Structure ◽  
Experimental Approaches ◽  
And Function

ABSTRACT Microbial mats are compacted, surface-associated microbial ecosystems reminiscent of the first living communities on early Earth. While often considered predominantly prokaryotic, recent findings show that both fungi and viruses are ubiquitous in microbial mats, albeit their functional roles remain unknown. Fungal research has mostly focused on terrestrial and freshwater ecosystems where fungi are known as important recyclers of organic matter, whereas viruses are exceptionally abundant and important in aquatic ecosystems. Here, viruses have shown to affect organic matter cycling and the diversity of microbial communities by facilitating horizontal gene transfer and cell lysis. We hypothesise fungi and viruses to have similar roles in microbial mats. Based on the analysis of previous research in terrestrial and aquatic ecosystems, we outline novel hypotheses proposing strong impacts of fungi and viruses on element cycling, food web structure and function in microbial mats, and outline experimental approaches for studies needed to understand these interactions.

scholarly journals Study on the Mechanism of Organic Matter Enrichment in Early Cambrian Marine Shales in the Lower Yangtze Area, South China: An Example Using Well JXY1

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Sihong Cheng ◽  
Bin Li ◽  
Kun Zhang ◽  
Weiwei Liu ◽  
Jun Peng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Oxygen Isotope ◽  
Water Body ◽  
Organic Carbon Content ◽  
Hydrocarbon Generation ◽  
Early Cambrian ◽  
Biological Productivity ◽  
Carbon And Oxygen Isotope ◽  
Lower Yangtze ◽  
Hydrothermal Activities

The abundance of organic matter in shales, which has a direct effect on the hydrocarbon generation potential of shales, is an important organic geochemical parameter for evaluating shale gas reservoirs. The total organic carbon content (TOC content) in shale is controlled by the abundance of original sedimentary organic matter. Therefore, it is very important to study the mechanism of organic matter enrichment in shale. In this paper, the Lower Cambrian marine shales from the Lower Yangtze region are selected as the research subject, most of which originate from a typical area well called Well JXY1. The degree of pyritization (DOP) is used to characterize the redox environment of the water body, while the P/Al ratio is used to analyze the biological productivity of paleoseawater. The paleosalinity of seawater is calculated via carbon and oxygen isotope analysis. In addition, the early Cambrian hydrothermal activities were studied by using core description; Si, Al, Fe, and Mn elemental analysis; and oxygen isotope calculations. The results show that during the early Cambrian Wangyinpu sedimentary period, the seawater was an anaerobic water body with H2S, and the oxygen concentration was approximately 0 mL/L. In the middle stages of the Wangyinpu sedimentary period, the water body had the strongest reducibility and the highest biological productivity. Moreover, the paleoocean in this period between the Yangtze plate and the Cathaysian plate was greatly affected by hydrothermal activities, with temperatures ranging from 90°C to 120°C. Active hydrothermal activities promoted high biological productivity and an anaerobic environment, both of which were conducive to the preservation and enrichment of organic matter, resulting in extremely high TOC content in the Wangyinpu shales (from 6.5% to approximately 16%).

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