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Terminal Ediacaran anoxia in deep-ocean: Trace element evidence from cherts of the Liuchapo Formation, South China

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Science China Earth Sciences 2009年第6期52卷 807-822页

作者： CHANG HuaJin CHU XueLei FENG LianJun HUANG Jing State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Graduate University of Chinese Academy of Sciences Beijing 100049China

Here we report a detailed trace element study of the cherts from Liuchapo Formation, which is a terminal Ediacaran (551-542 Ma) succession in South China deposited in deep-water basinal setting. The REE of Liuchapo cherts shows similar features as observed for anoxic modern seawater (but not for hydrothermal fluids), characterized by positive La anomaly (LaN/CeN = 0.83–1.91, average 1.37), moderately negative Ce anomaly (0.53–1.1, average 0.73), positive Gd anomaly (average 1.08), positive Y anomaly (average 1.21), and depleted LREE and MREE. In addition, the Liuchapo cherts have low ΣREE (3.36–56.13 ppm, average 20.6 ppm), low Al2O3, Ti, Th and Zr concentrations, and high Y/Ho ratios (up to 43.9). The redox-sensitive trace elements concentrations in the cherts do not correlate with detrital input proxies. All of these features suggest that the redox-sensitive trace elements in the cherts were authigenically concentrated in water column and their concentrations thus are excellent indicators of ancient redox conditions. Very low Th/U ratios, high V/(V+Ni) and Fe?/Al ratios, enrichments of redox-sensitive trace elements (U, V, Mo), and low concentration of Mn in the cherts imply anoxia in the deep seawater. Our data reveal that the terminal Ediacaran ocean was not completely oxidized and the deep ocean was still anoxic, at least in South China. We propose that although the oxidative events existed in the terminal Ediacaran oceans, decomposition of organic matter prolonged anoxia in the deep ocean.

关键词： chert anoxia trace elements redox proxy Ediacaran South China

Isoflurane preserves energy balance in isolated hepatocytes during in vitro anoxia/reoxygenation

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World Journal of Gastroenterology 2005年第25期11卷 3920-3924页

作者： QuanLi Wei-FengYu Mai-TaoZhou XinLu Li-QunYang MingZhu Jian-GangSong Jun-HuaLu DepartmentofAnesthesiology EasternHepatobiliarySurgeryHospitaltheSecondMilitaryMedicalUniversityShanghai200438China DepartmentofClinicalSurgery EasternHepatobiliarySurgeryHospitaltheSecondMilitaryMedicalUniversityShanghai200438China

AIM: To investigate the protective effect of isoflurane on energy balance in isolated hepatocytes during in vitro anoxia/reoxygenation, and to compare isoflurane with halothane. METHODS: Hepatocytes freshly isolated from fed rats were suspended in Krebs-Henseleit buffer, and incubated in sealed flasks under O2/CO2 or N2/CO2 (95%/5%, V/V) for 30 or 60 min, followed by 5 or 10 min of reoxygenation, with an added volatile anesthetic or not. ATP, ADP, and adenosine monophosphate in hepatocytes were determined by high performance liquid chromatography, and energy charge was calculated. RESULTS: During 30 min of anoxia, the energy charge and total adenine nudeotide steadily increased with the isoflurane dose from 0 to 2 minimum alveolar anesthetic concentration (MAC), then decreased from 2 to 3 MAC. In short incubations (30-35 min) at 1 MAC isoflurane, energy charge modestly decreased during anoxia, which was partially prevented by isoflurane and completely reversed by reoxygenation, and total adenine nudeotide did not decrease. In long incubations (60-70 min), both energy charge and total adenine nudeotide greatly decreased during anoxia, with partial and no reversal by reoxygenation, respectively. Isoflurane partly prevented decreases in both energy charge and total adenine nudeotide during anoxia and reoxygenation. In addition, 1 MAC isoflurane obviously increased ATP/ADP, which could not be changed by 1 MAC halothane. CONCLUSION: Isoflurane partially protects isolated hepatocytes against decreases in both energy charge and total adenine nudeotide during short (reversible) or long (irreversible) anoxia.

关键词： Isoflurane Hepatocytes anoxia Energy balance

Changes of summating potentials and morphology in theguinea pig cochlea during anoxia

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Chinese Journal of Acoustics 1995年第4期14卷 358-363页

作者： LI Xingqi SUN Jianhe SUN Wei and JIANG Sichang(Institute of Oiorhinolaryngology PLA, General Hospital, Beijing 100853)

The dynamic changes in CAP, and EP in the scale media were examined with single micropipet during anoxia and reventilation with oxygen. Also, the morphologic changes in IHC, OHC and synapse were observed in this experiment. It was found that the amplitude of SP and EP values declined with alteration in polarity of these value. The changes in polarity and amplitude of SP followed the changes of CAP threshold induced by anoxia. The histologic examinations revcaled no cvidence of acetylcholinesterase (AChE) alteration in the synapse and no succinict dehydrogenase (SDH) changes in IHC appeared. However, the activity of SDH in the OHC decreased. The results suggest that the polarity and amplitude of SP were influenced passively by the changes of EP value. In addition, the change of SP polarity from positive tonegative during anoxia is due to the loss of mudulation process of OHC to IHC, while the SP polarity from negative to positive during the supply of oxygen is caused by regain of the modulation process of OHC.

关键词： Audiometry Evoked response anoxia

Ecological Devastation in Lake Victoria: Part A: Thermal Structure and anoxia

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Open Journal of Ecology 2015年第7期5卷 287-298页

作者： Moshe Gophen Migal-Scientific Institute Kiryat Shemone Israel

Lake Victoria is the second (excl. Caspian Sea) largest lake in the world by surface area and 7th by Volume. The lake and catchment territories are shared between three countries, Kenya, Uganda and Tanzania. A research was carried out during 1990-1992 exploring the changes of the thermo-chemical structure occurred after the invasion of Nile Perch. Results of changes of physico-chemical (Temperature, DO and pH) conditions are summarized in this paper. The anoxic conditions by space and time were enhanced. Enhancement of pollutant supply from anthropogenic developments of terrestrial sources and atmospheric dust deposition accompanied by the deleterious effects of the Nile Perch invasion caused enhancement of anoxia in the lake in space and time. The combination of bottom-up nutrient supply and strong mixing conditions, expressed as low RTR values accelerate phytoplankton growth rate and production. The surplus of organic matter originated from algal biomass, enhanced anoxia.

关键词： Lake Victoria Kenya Nile Perch anoxia Thermal Stability

Epidemio-Clinical Characteristics of Perinatal anoxia and Immediate Outcome of Patients at Hospital Teaching Gabriel Toure of Bamako

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Open Journal of Pediatrics 2019年第4期9卷 326-336页

作者： L.N.Sidibe H.Diall1,D.Konate O.Coulibaly F.L.Diakite K.Sacko F.Traore O.H.Diallo L.Maiga I.Ahamadou I.Traore I.Kone1,B.Maiga P.Togo A.K.Doumbia A.Toure E.M.Cisse A.Dembele Y.A.Coulibaly A.Doumbie A.Konare1,A.A.Diakite B.Togo M.Sylla F.DickoTraore Department of Pediatrics CHU Gabriel ToureBamakoMali Faculty of Medicine and Odonto-Stomatology of Mali BamakoMali

Introduction: Neonatal asphyxia (NA) is one of the most likely causes of neuro-developmental abnormalities in children. In Mali it is responsible for half of the early deaths and the third of neonatal mortality. Updated data would help understand and improve intervention strategies to reduce mortality. Objective: It is the study of epidemiological and clinical characteristics, the immediate outcome and the factors associated with newborn (NB) mortality with NA. Material and Methods: This was a prospective cross-sectional study from June 27th to September 3rd 2016 about the NBs admitted for NA in the Hospital Teaching Gabriel Touré of Bamako. The clinical and biological data including the prognosis were collected from the health records of women, the liaison sheets and the medical file. The analysis was done using the software Epi info version 3.5.1. Results: 76 NBs were included which represented 23.45% of hospitalizations. The majority (89.5%, n = 68) were admitted to less than 24 hours of life for NA grade III according to the Sarnat classification (43.4%, n = 33). The average age of mothers was 24.17 ± 5.5 years. Almost half (41.3%, n = 31) were primigravida. The most common obstetrical event was dystocia (64.5%, n = 49). The prognosis was poor in grade III anoxia in our patients (56%) of deaths. Conclusion: The périnatal anoxia (PA) is a major health issue in Mali because of its frequency and severity. Monitoring of pregnancies, delivery assisted by skillful and qualified personnel, mastery of neonatal resuscitation techniques are good means of prevention.

关键词： anoxia Newborn Epidemiology Clinical Outcome

Anaerobic Induction of Isocitrate Lyase and Malate Synthase in Submerged Rice Seedlings Indicates the Important Metabolic Role of the Glyoxylate Cycle

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Acta Biochimica et Biophysica Sinica 2005年第6期37卷 406-414页

作者： Ying LU~(1.2) Yong-Rui WU~(1.2) Bin HAN~(1.3) 1 National Center for Gene Research. Shanghai Institutes for Biological Sciences. Chinese Academy of Sciences. Shanghai 200233. China. 2 Graduate School of the Chinese Academy of Sciences. Beijing 100039.China 3 Institute of Plant Physiology and Ecology. Shanghai Institutes for Biological Sciences. Chinese Academy of Sciences. Shanghai 200032. China National Center for Gene Research Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai 200233 China Graduate School of the Chinese Academy of SciencesBeijing 100039 China Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai 200032 China

The glyoxylate cycle is a modified form of the tricarboxylic acid cycle that converts C2compounds into C4 dicarboxylic acids at plant developmental *** studying submerged rice seedlings,we revealed the activation of the glyoxylate cycle by identifying the increased transcripts of mRNAs of thegenes of isocitrate lyase(ICL)and malate synthase(MS),two characteristic enzymes of the *** blot analysis showed that ICL and MS were activated in the prolonged anaerobic *** activity assay of pyruvate decarboxylase and ICL in the submerged seedlings indicated an 8.8-fold and3.5-fold increase over that in the unsubmerged seedlings,*** activity assay of acetyl-coen-zyme A synthetase in the submerged seedlings indicated a 3-fold increase over that in the unsubmergedseedlings,which is important for initiating acetate ***,we concluded that the glyoxylatecycle was involved in acetate metabolism under anaerobic conditions.

关键词： Oryza sativa glyoxylate cycle isocitrate lyase malate synthase acetyl-coenzyme A synthetase anoxia

Effect of dissolved oxygen on methane production from bottom sediment in a eutrophic stratified lake

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Journal of Environmental Sciences 2023年第3期125卷 61-72页

作者： Yasuyuki Maruya Keisuke Nakayama Masafumi Sasaki Katsuaki Komai Graduate School of Engineering Kyushu University744 MotookaNishi-KuFukuoka 819-0395Japan Graduate School of Engineering Kobe UniversityRokkodai-Cho 1-1Nada-KuKobe 657-8501Japan Department of Engineering Kitami Institute of TechnologyKohen-Cho 165Kitami 090-8507Japan

Clarifying the role of sulfate and dissolved oxygen (DO) in methane production may allow for precise and accurate modeling of methane emissions in eutrophic *** conducted field observations of sulfate,methane,and DO concentrations in Lake Abashiri,a typical brackish and eutrophic lake in a cold region,to develop a DO-based method for quantitively estimating methane production in a eutrophic lake and analyzed the *** found that sulfate concentrations decreased rapidly from 900.0 mg/L in water overlying the sediments to nearly 0.0 mg/L in the bottom *** production was almost uniform across sediment depths of 0.05 to 0.25 m,ranging from 1400 to 1800μmol/m^(2)/***,methane production was found to be a function of DO concentrations in water overlying the bottom and could be modeled by a logistic function:constant production at 1,400μmol/m^(2)/day for DO concentrations of 0.0 to 3.0 mg/L,rapidly decreasing to 0μmol/m^(2)/day for DO concentrations of 3.0 to 6.0 mg/*** methane model was verified using a simple one-dimensional numerical model that showed good agreement with field *** results thus suggest that the proposed methane model reduces uncertainty in estimating methane production in a eutrophic lake.

关键词： Dissolved oxygen(DO) Stratification Methane anoxia Numerical simulation

Meiofauna distributions at the oxygen minimum zone in Changjiang (Yangtze) River Estuary waters

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Acta Oceanologica Sinica 2006年第5期25卷 120-134页

作者： HUA Er ZHANG Zhinan ZHANG Yan College of Marine Life Science Ocean University of China Qingdao 266003 China

A quantitative study on meiofauna was carried out along a transect throughout the Changjiang Estuary＇ s oxygen minimum zone （OMZ） in the East China Sea. There exist two distinct station groups in the OMZ： the fine-grained hypoxic area and the more fine-grained anoxie area. Meiofauna abundance ranged from （ 101.5±31.0） ind./cm^2 （ hypoxie area） to （369.9±123.9） ind./cm^2（ anoxic area） along the transect. Free-living marine nematodes were the numerically dominant meiofauna at every station. The anoxic area differed significantly in meiofauna abundance and vertical distribution pattern from the hypoxic area. Within the anoxic area, nematodes abundance increased and amounted to over 90% of the total meiofauna; about 50% of nematodes were found in the 2-5 and 5-8 cm layers. At hypoxie stations, about over 85 % were restricted to the top 2 cm. Benthic eopepod abundance and dominance decreased consistently with the oxygen gradient. The pattern of meiofauna biomass was similar to that of abundance. The correlation analysis of the meiofauna numbers and environmental parameters indicated that abundance and biomass of total meiofauna and nematodes had significant or highly significant （ P 〈 0.05 or P 〈 0.01 ） correlations with Chl a and Pha a, but no significant （ P 〉 0.05 ） correlations with bottom-water oxygen （ BWO2 ）. On the other hand, there was a highly significant positive correlation between benthic eopepod abundance and bottom-water oxygen （P 〈 0.05 ）. The investigation on the nematode community structure indicated that two different nematode communities existed in hypoxic and anoxic areas. In certain way, the shift in nematode species composition distinguishes the anoxia to hypoxia. Nematode diversity was generally lower within the anoxic stations than the hypoxic ones, but the difference was not significant. Indices of the nematode community structure varied in relation to the bottom-water oxygen together with bottom-water temperature, Chl a concentration and median

关键词： meiofauna free-living marine nematodes oxygen minimum zone hypoxia anoxia Changjiang estuary EastChina Sea

Coupling relationships between brachiopods and Girvanella during the Late Devonian F-F transition in Guilin, South China

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Science China Earth Sciences 2008年第11期51卷 1581-1588页

作者： XU Ran GONG YiMing ZENG JianWei Key Laboratory of Biogeology and Environmental Geology of Ministry of Education State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China Institute of Resources and Environment Key Laboratory of Biogenic Traces&Sedimentary Minerals of Henan ProvinceHenan Polytechnic UniversityJiaozuo 454003China

The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian transition. The living activity of brachiopods such as grazing and borrowing did great damage to the growth of Girvanella. However, there was more to just a mere a survival competing relationship between them, Girvanella actually improved marine environments by oxygenating the dysoxic ambient sea-water through photosynthesis in the lower Kellwasser Horizon. Profited from this improvement brachiopods' abundance increased subsequently and suppressed Girvanella again. Nonetheless, without Girvanella's photosynthesis, brachiopods were wiped out by the farther anoxic environments in the upper Kellwasser Horizon. The complex relationships between Girvanella and brachiopods may be a key to unlocking the relationships between geomicrobes and metazoans in the geological overturn periods.

关键词： brachiopods Girvanella anoxia Late Devonian F-F mass extinction South China