Carbon dioxide biogenic

Piperidine alkaloids contain the piperidine nucleus. The structural development of this group of alkaloids in synthesis is presented in Figure 52. Here a is L-lysine and /3 is cadaverine. The basic ring of j3 is the same as in a, although the activity of PLP reduces carbon dioxide. The j3 is biogenic amine, neither a stable nor a poisonous compound... 

Coplan JD, Trost R, Owens MJ (1998b) Cerebrospinal fluid concentrations of somatostatin and biogenic amines in grown primates reared by mothers exposed to manipulated foraging conditions. Arch Gen Psychiatry 55 473-477 Coryell W (1997) Hypersensitivity to carbon dioxide as a disease-specific trait marker. Biol Psychiatry 41 259-263... 

The hydrate recovered consisted of methane ( 99%), with minor to trace amounts of carbon dioxide (1.22%), ethane (86 ppmv), propane (2 ppmv), with a volumetric ratio of methane to water of 154. The chlorinity concentration (57.2 mM) of water collected indicated that the sample was a mixture of 10% pore water and 90% freshwater. The gas water ratio exceeded 170, higher than any previously reported for in situ hydrates. The C1/C2 ratio was 11,500, compared to a headspace value three times lower however, both gas ratios indicate biogenic gas. 

The concentrations of gases in the core voids were measured, with C i /C2 ratios from approximately 1,200 to 39,000 indicating biogenic sources. Concentrations of propane through heptane were usually below 10 ppmv, and the concentration of carbon dioxide varied widely from 0% to 20% of the free gas. 

Stange G. (1996) Sensory and behavioural responses of terrestrial invertebrates to biogenic carbon dioxide gradients. In Advances in Bioclimatology Vol. 4, ed. G. E. Stanhill, pp. 223-253. Springer Verlag, Berlin. 

Dreybrodt, W., 1982, A possible mechanism for growth of calcite speleothems without participation of biogenic carbon dioxide. Earth Planet. Sci. Lett. 58 293-299.. 

One of the drawbacks of using this technique is the need to freeze the canned samples if they cannot be analysed within one or two weeks of their collection. Failure to follow this procedure can create problems because of the generation of biogenic gas in the cans or the bacterial oxidation of the hydrocarbon gases to carbon dioxide. 

Farooqui T, Robinson K, Vaessin H, Smith BH (2003) Modulation of early olfactory processing by an octopaminergic reinforcement pathway in the honeybee. J Neurosci 23 5370-5380 Faucher C, Forstreuter M, Hilker M, de Bruyne M (2006) Behavioral responses of Drosophila to biogenic levels of carbon dioxide depend on life-stage, sex and olfactory context. J Exp Biol 209 2739-2748... 

Calcite cement in shallow marine sandstones normally cannot be derived from sources outside the sandstones owing to alack of viable transport mechanisms for significant amounts of dissolved calcium carbonate. Within the sandstones the only significant source of calcite cement is usually biogenic carbonate, which is consequently considered to be the dominant source of calcite cement within shallow marine sandstones. Influx of carbon dioxide into a sandstone will not lead to precipitation of additional calcite cement unless a source of calcium other than biogenic carbonate is present, but the carbon isotopic composition of the calcite cement may be strongly affected. 

Sedimentary lamination is also caused by the deposition of calcium carbonate and is important in most freshwater lakes where the clastic input from rivers is low. Carbonate deposits may be chemical or biogenic (see Box 1.1). As with phytoplanktonic production, the abiogenic (chemical) precipitation of calcium carbonate is seasonal, occurring during the warmer months. During this period carbon dioxide is removed from the water by planktonic photosynthesis, which causes water acidity to decrease and calcium carbonate to precipitate. From the equilibrium in Eqn 3.9c (Box 3.12) it can be seen that if the amount of C02(aq) decreases, more C02(aq) and carbonate are produced from bicarbonate, which increases the concentration of carbonate and promotes its precipitation. Subsequently, the water becomes more acidic and no longer supersaturated with respect to calcite (the main form of crystalline calcium... 

---