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Anoxia consequences

As seen in Figure 6, mean 8 Mo in these ancient sediments is significantly offset from that of modem seawater and from mean 8 Mo of recent euxinic sediments. The offset is in the direction of less fractionation of Mo isotopes in the oceans (closer to the likely 5 MOjj ), as would be expected if removal of Mo to euxinic sediments expanded at the expense of removal to oxic (and suboxic) sediments. The result is consistent with the hypothesis of expanded ocean anoxia, and consequent increase in the areal extent of euxinic depositional settings, during this time. A similar, albeit smaller, offset is seen in repeated measurements of a Devonian black shale sample (USGS SDO-1 Fig. 6). This shift could he interpreted as consistent with somewhat expanded euxinic deposition during this time—an interpretation consistent with other evidence of expanded Paleozoic ocean anoxia in inland hasins. While further work is needed, these initial results are promising. [Pg.449]

Some substances, such as carbon monoxide and barbiturates, can deprive brain cells of oxygen or glucose - they produce anoxia - with potentially serious consequences for gray matter. Other substances, such as lead, hexachlorophene, and the antitubercular drug isoniazid, are capable of causing loss of myelin, a coating or sheath for the axon and dendrites that extend from the central unit (cell body) of neurons. Demyelination can occur in either the CNS or PNS. [Pg.123]

The affinity of the remaining heme groups for oxygen is increased, and so the dissociation curve is also distorted. The consequence of this is that the tissue anoxia is very... [Pg.363]

Cyanide also causes endogenous catecholamine release (Kanthasamyeta/., 1991 Kawada eta/., 2000 Schomiget a/., 1995 Inoue et al, 1998). Inoue et al (1998) also point out that cyanide-produced depolarization increases intracellular calcium due to the suppression of the potassium channels and activation of the voltage-dependent calcium channel. Anoxia induces suppression of the sodium pump and activates cation channels due to the decrease in ATP. A further consequence of the presence of cyanide in the tissue is inhibition of the Na+/Ca + exchanger (NCX) (Ju and Allen, 2005). NCX is important for the pacemaker currents. Metabolic inhibition of NCX reduces the firing rate of pacemaker cells. [Pg.502]

Other methods proposed for ocean sequestration may lower costs but present significant obstacles. One scenario envisions fertilization of the oceans with iron. However, studies of this method have indicated that only about 10 percent of the carbon fixed remains in the ocean. Also, the unintended ecological consequences of this method, such as abyssal nitrogen anoxia and risks to fisheries, may far exceed the benefit derived from carbon sequestration. [Pg.79]

Figure 4 Progressive changes in fish and invertebrate fauna as oxygen concentration decreases from 2mgl to anoxia. From Rabalais NN, Harper DE, Jr., and Tuner RE (2001) Responses of nekton and demersal and benthic fauna to decreasing oxygen concentrations. In Rabalais NN and Turner RE (eds.) Coastal and Estuarine Studies 58 Coastal Hypoxia Consequences for Living Resources and Ecosystems, pp. 115-128. Washington, DC American Geophysical Union. Figure 4 Progressive changes in fish and invertebrate fauna as oxygen concentration decreases from 2mgl to anoxia. From Rabalais NN, Harper DE, Jr., and Tuner RE (2001) Responses of nekton and demersal and benthic fauna to decreasing oxygen concentrations. In Rabalais NN and Turner RE (eds.) Coastal and Estuarine Studies 58 Coastal Hypoxia Consequences for Living Resources and Ecosystems, pp. 115-128. Washington, DC American Geophysical Union.
As depicted in Fig.3, the concentration of increased 3-fold in hepatocytes subjected to anoxia. This increase proceeded more rapidly in hepatocytes from starved rats than in those from fed animals, as a consequence of the faster degradation of ATP in the former situation. Measurements of the concentration of GTP in the hepatocytes showed that it decreased in parallel with that of ATP under both nutritional conditions (results not shown). [Pg.473]

The protective action of tissue anoxia has been reviewed.Because protection of mammals by serotonin, PAPP, etc. has been ascribed to their vasoconstrictive activity with consequent tissue anoxia, it was surprising to learn that the serotonin-creatinine sulfate complex protected both planarla and bean sprouts,where vasoconstriction cannot be a factor. [Pg.349]


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Anoxia

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