Influence of dissolved oxygen on secular patterns of marine microbial carbonate abundance during the past 490 Myr

Riding, Robert,Liang, Liyuan,Lee, Jeong-Hyun,Virgone, Auré,lien Elsevier 2019 Palaeogeography, palaeoclimatology, palaeoecology Vol.514 No.-

<P><B>Abstract</B></P> <P>Shallow marine benthic microbial carbonate sediments declined episodically during the Phanerozoic. They were relatively abundant during the Cambrian/mid-Ordovician, late Devonian/Mississippian, mid-Permian/mid-late Triassic, and to a lesser degree in the late Jurassic/early Cretaceous. They were least abundant when invertebrate, especially reef, diversity was relatively high in the mid-Ordovician/late Devonian, early-mid Permian, late Triassic, mid-late Jurassic, and early Cretaceous to present-day. These intervals of microbial carbonate abundance and invertebrate diversity generally alternate transitionally with one-another; but ‘lows’ and periods of overlap also occur. ‘Lows’, when benthic microbial carbonate abundance and invertebrate diversity both declined, are apparent during the Pennsylvanian and early-mid Jurassic. Overlaps, when microbial carbonates and invertebrates were both relatively common, occur in the early Cambrian and late Jurassic. Overall, these patterns broadly support suggestions that microbial carbonate abundance declined as calcified invertebrates increased. To further explore these relationships, we compared microbial carbonate abundance and invertebrate diversity with estimates of changes in sea-surface temperature and marine dissolved oxygen for the past 490 Myr. This analysis suggests that invertebrate diversity varied directly with oxygen availability. Invertebrate diversity was low when dissolved oxygen was low in the early Ordovician, late Devonian, early Triassic, and early-mid Jurassic. It appears that, by reducing invertebrate diversity, low oxygen levels favored microbial carbonates. At the same time, low oxygen levels likely stimulated anaerobic metabolisms favoring carbonate precipitation. This study suggests that dissolved oxygen was a major control on secular patterns of marine microbial carbonate abundance during the Phanerozoic, together with marine temperature and carbonate saturation state.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phanerozoic intervals of microbial carbonate abundance alternate with intervals when invertebrate diversity increased. </LI> <LI> Marine invertebrate diversity varies directly with dissolved oxygen level. </LI> <LI> Microbial carbonate abundance varies inversely with dissolved oxygen. </LI> </UL> </P>

Marine oxygenation, lithistid sponges, and the early history of Paleozoic skeletal reefs

Lee, Jeong-Hyun,Riding, Robert Elsevier 2018 Earth-science reviews Vol.181 No.-

<P><B>Abstract</B></P> <P>Microbial carbonates were major components of early Paleozoic reefs until coral-stromatoporoid-bryozoan reefs appeared in the mid-Ordovician. Microbial reefs were augmented by archaeocyath sponges for ~15 Myr in the early Cambrian, by lithistid sponges for the remaining ~25 Myr of the Cambrian, and then by lithistid, calathiid and pulchrilaminid sponges for the first ~25 Myr of the Ordovician. The factors responsible for mid–late Cambrian microbial-lithistid sponge reef dominance remain unclear. Although oxygen increase appears to have significantly contributed to the early Cambrian ‘Explosion’ of marine animal life, it was followed by a prolonged period dominated by ‘greenhouse’ conditions, as sea-level rose and CO<SUB>2</SUB> increased. The mid–late Cambrian was unusually warm, and these elevated temperatures can be expected to have lowered oxygen solubility, and to have promoted widespread thermal stratification resulting in marine dysoxia and hypoxia. Greenhouse conditions would also have stimulated carbonate platform development, locally further limiting shallow-water circulation. Low marine oxygenation has been linked to episodic extinctions of phytoplankton, trilobites and other metazoans during the mid–late Cambrian. We propose that this tendency to dysoxia-hypoxia in shallow marine environments also limited many metazoan reef-builders. In contrast, during the mid–late Cambrian, the ability of lithistid sponges to withstand low oxygen levels allowed them to create a benthic association with microbial carbonates that dominated global reefs. These conditions ameliorated during the Ordovician, as temperature decline promoted ocean ventilation. The prolonged time gap occupied by low diversity reefs between the ‘Cambrian Explosion’ and the ‘Great Ordovician Biodiversification Event’ reflects elevated temperatures and reduced marine oxygenation that limited metazoan diversification in shallow marine environments.</P>

Lithistid sponge-microbial reefs, Nevada, USA: Filling the late Cambrian ‘reef gap’

Lee, Jeong-Hyun,Dattilo, Benjamin F.,Mrozek, Stephanie,Miller, James F.,Riding, Robert Elsevier 2019 Palaeogeography, palaeoclimatology, palaeoecology Vol.520 No.-

<P><B>Abstract</B></P> <P>Cambrian–Ordovician sponge-microbial mounds in the Great Basin of the western USA reveal reef structure and composition immediately prior to the Great Ordovician Biodiversification Event (GOBE). Here we describe lithistid sponge-microbial reefs from the upper Cambrian (Furongian, Stage 10) strata of the Arrow Canyon Range, Nevada. The reefs are mound-like structures up to 1 to 2 m high and a few meters wide that consist of an unidentified thin-walled, bowl-shaped anthaspidellid sponge, columnar microstromatolite fabric, and the calcified microbe <I>Angusticellularia</I>. The reefs formed in low-energy, subtidal environments in which lime mud filled spongocoels and inter-reef spaces around undisturbed, in place, thin-walled sponges. The reefs colonized stable substrates provided by oolitic and bioclastic grainstone shoals. The mutually attached lithistid sponges form the main framework of the reefs. These thin-walled and bowl-shaped lithistids most likely were adapted to low-energy environments. Spaces beneath the overhanging sponge walls were filled by microbial carbonates. These include pendent micro-dendritic <I>Angusticellularia</I> attached to dermal sponge surfaces and upward-growing masses of microstromatolites. After death the lithistid spongocoels were mainly filled by micritic sediment that hosted soft-bodied burrowing organisms and keratose-like sponges. These lithistid sponge-microbial reefs, together with an earlier example of late Cambrian (Paibian) dendrolite-lithistid reefs in the same area, characterize skeletal-microbial reefs immediately prior to the GOBE.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lithistid sponges formed reef frameworks in the upper Cambrian of Nevada, USA. </LI> <LI> Reefs dominated by thin-walled sponges developed under low-energy conditions. </LI> <LI> Spaces beneath the overhanging sponge walls were filled by microbial carbonates. </LI> <LI> In the Great Basin, gradual reef transition occurred across Cambro-Ordovician boundary. </LI> <LI> Regional disparities in reef evolution pattern during early stage of the GOBE are recognized. </LI> </UL> </P>

Early recovery of sponge framework reefs after Cambrian archaeocyath extinction: Zhangxia Formation (early Cambrian Series 3), Shandong, North China

Lee, J.H.,Hong, J.,Choh, S.J.,Lee, D.J.,Woo, J.,Riding, R. Elsevier 2016 Palaeogeography, palaeoclimatology, palaeoecology Vol.457 No.-

Reefs dominated by the anthaspidellid sponge Rankenella zhangxianensis, the calcimicrobe Epiphyton and the stem-group cnidarian Cambroctoconus orientalis, together with encrusting microstromatolites occur early in the middle Cambrian (Series 3, late Stage 5) of Shandong, eastern China. In the Zhangxia Formation, these in situ components created a tight framework, with centimeter-scale growth cavities mainly filled by fine-grained matrix. Among them, R. zhangxianensis and C. orientalis mutually attached and locally formed metazoan-dominated frameworks. These metazoan-microbial reefs form thin lenses <2m wide within microbial mounds, and probably developed at least a few centimeters of synoptic relief above these surrounding structures. With an age of >505Ma, these Rankenella reefs indicate recovery of framework-building metazoans within ~5millionyears of the archaeocyath reef decline. In structure, they resemble archaeocyath reefs as well as Early Ordovician lithistid sponge-microbial reefs, having conjoined conical macroskeletons thickly veneered by calcimicrobes and microbial carbonate with largely matrix-filled intervening cavities. In combination with other sponge-microbial reefs reported from Australia, Iran, Korea and the USA, they demonstrate that an anthaspidellid sponge-microbial reef consortium was widespread throughout the mid-late Cambrian.

A review on development in design of multistage centrifugal pump

Rode, Bhushan R.,Khare, Ruchi Techno-Press 2021 Advances in computational design Vol.6 No.1

Multi-stage pumps are the most popular pumps among various kinds of centrifugal pumps. Athorough review of different kinds of literature has led to the conclusion that there is a desperate need to increase the performance of the multi-stage centrifugal pump. Many investigators have put their efforts to increase the pump performance and also the work is being projected on various aspects of pump performance variables. To improve the multistage centrifugal pump performance by investigation, modification, and analysis many works of literature are available. For analysis, many researchers used the Navier-Stokes solver to create the three-dimensional unsteady turbulent flow numerical model with the standard k-ε turbulent equation. This paper mainly focuses on research related to the multi-stage centrifugal pump.

Synthesis and Evaluation of Stearic Acid Derivatives as Cetane Number Improvers

Rode, Ambadas B.,Thajudeen, H.,Chung, Keun-Woo,Kim, Young-Wun,Hong, In-Seok Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.6

1,2,4,5-tetraoxane, mono and dinitrate glycerol carbonate ester derivatives of stearic acid were synthesized along with the known 9(10)-keto methyl sterate, methoxy mono-nitrate and dinitrate of methyl stearate. Their cetane numbers (CNs) were investigated to evaluate their viability for use as CN improvers. The CN performances of tetraoxane and all of the nitrate derivatives were investigated at 500 and 1000 ppm concentrations and compared to that of a traditional CN improver 2-ethylhexyl nitrate (2-EHN). The experimental results suggest that all derivatives evaluated in this study showed better CN improvement than base diesel fuel. Specifically, the 1,2,4,5-tetraoxane derivative of stearic methyl ester was superior to all derivatives studied, also being superior to 2-EHN. We also discussed the correlations between the observed CN trends and thermo-analytical data resulted from thermo gravimetric analysis curves (TGA) and differential scanning calorimetry (DSC).

An Efficient One-pot N-Acylation of Deoxy- and Ribo-cytidine Using Carboxylic Acids Activated in situ with 2-Chloro-4,6-dimethoxy-1,3,5-triazine

Rode, Ambadas B.,Son, Sang-Jun,Hong, In-Seok Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.7

An Efficient One-pot N-Acylation of Deoxy- and Ribo-cytidine Using Carboxylic Acids Activated in situ with 2-Chloro-4,6-dimethoxy-1,3,5-triazine

Ambadas B. Rode,손상준,홍인석 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.7

Synthesis and Evaluation of Stearic Acid Derivatives as Cetane Number Improvers

Ambadas B. Rode,Young-Wun Kim,Keunwoo Chung,H. Thajudeen,In Seok Hong 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.6

1,2,4,5-tetraoxane, mono and dinitrate glycerol carbonate ester derivatives of stearic acid were synthesized along with the known 9(10)-keto methyl sterate, methoxy mono-nitrate and dinitrate of methyl stearate. Their cetane numbers (CNs) were investigated to evaluate their viability for use as CN improvers. The CN performances of tetraoxane and all of the nitrate derivatives were investigated at 500 and 1000 ppm concentrations and compared to that of a traditional CN improver 2-ethylhexyl nitrate (2-EHN). The experimental results suggest that all derivatives evaluated in this study showed better CN improvement than base diesel fuel. Specifically, the 1,2,4,5-tetraoxane derivative of stearic methyl ester was superior to all derivatives studied, also being superior to 2-EHN. We also discussed the correlations between the observed CN trends and thermo-analytical data resulted from thermo gravimetric analysis curves (TGA) and differential scanning calorimetry (DSC).

Positive magnetisation in carbon nanostructures

A.V. Rode,A.G. Christy,N.R. Madsen,E.G. Gamaly,S.T. Hyde,B. Luther-Davies 한국물리학회 2006 Current Applied Physics Vol.6 No.3

Carbon nanoclusters produced by high-repetition-rate laser ablation of glassy carbon in Ar exhibits para- and ferromagnetic behav-iour up to 90 K, showing a narrow hysteresis curve with a coercive forceHc = 420 Oe, remnant magnetisation of 5· 10. 3 emu/g, sus-ceptibility of the order of 10. 5 emu/g Oe and saturation magnetization 0.30.8 emu/g at 1.8 K. We consider briey the mechanism offormation of clusters in the laser-ablated vapour and structural characteristics of the nanoclusters, which show the presence of graph-ite-like sheets with hyperbolic curvature, as proposed for ‘‘schwarzite’’. We postulate that localized unpaired spins occur because of topo-oered by the convoluted sheets.