Long-term fluxes

F or NjO, estimates of soil emissions are perhaps slightly more straightforward, simply because so much more information on soil NjO emissions is available. For agricultural soils, estimates as a percentage of fertilizer input have been published " and, for the remaining land use classes listed in Table 5, mean annual emissions from a series of long-term flux measurements are available. The total annual soil NjO emissions for the ElK (27 kt N) are very similar to the annual soil NO emissions. Soils, however, have by far a greater impact on the... 

Keywords Carbonate dissolution, Dissolved flux, Dissolved load, Ebro River basin, Evaporite dissolution, Long-term fluxes... 

Negrel P, Roy S, Petelet-Giraud E, Millot R, Brenot A (2007) Long-term fluxes of dissolved and suspended matter in the Ebro River Basin (Spain). J Hydrol 342(3 1) 249-260... 

Regnier, P., Wollast, R., and Steefel, C.I. (1997) Long term fluxes of reactive species in macrotidal estuaries Estuaries from a fully transient, multi-component reaction transport model. Mar. Chem. 58, 127-145. 

When operating the backflushing system optimally the resulting flux with rapid backflushing can be 20 to 30 times higher than the long-term flux in the absence of backflushing [Redkar and Davis, 1995]. 

Although weathering of siliceous minerals by CO2 (the so-called Urey reactions but see (Berner and Maasch, 1996)) contributed to the long-term flux of silica to the oceans (Berner, 1990), and potentially fostered the radiation of diatoms in the Cenozoic, by itself, orogeny cannot explain the relatively sharp increase in diatoms at the Eocene/Oligocene boundary. Indeed, the seawater strontium isotope record does not correspond with these radiations in diatoms (Raymo and Ruddiman, 1992). We must look for other contributing processes. 

Lecuyer, C. Ricard, Y. 1999. Long-term fluxes and budget of ferric iron implication for the redox state of the Earth s mantle and atmosphere. Earth and Planetary Science Letters, 165,197-211. 

There are, however, two main reasons why this must be a minimum estimate of the amount of sediment recycled into the mantle over geological time. These are, first, reintroduction of CO2 into the atmosphere via arc volcanism, and second, the fact that purely clastic sediments are ignored in this mass balance. CO2 is reintroduced into the atmosphere as a result of decarbona-tion reactions in calc-silicate rocks (the reverse Urey reaction ), requiring further weathering and photosynthesis to remove it. Fluxes associated with these processes over Phanerozoic time have been reviewed by Berner et al. (1983) and Berner (1991), who concluded that such addition of CO2 by (mainly arc) volcanism and its drawdown by silicate weathering have been the major long-term fluxes over this period, and that drawdown has only slightly outstripped... 

There are two categories of flux depicted in Fig. 11.1 long-term fluxes, indicated by dashed arrows, and short-term fluxes, indicated by solid arrows. The long-term fluxes represent fluxes... 

Figure 3.59 Long term flux decay and restoration by cleaning.

Figure 3.60 Effect of cross-flow velocity on long term flux decay.

Figure 3.63 Effect of "charged" membrane on long term flux decay with cathodic paint.

All concentrations and isotopic compositions of noble gases and parent elements are assumed to be in steady state (and uniform) over the last residence time. Note that a crustal reservoir is not included in the model, because neither the long-term depletion of parent element mantle concentrations, nor the long-term flux of daughter nuclides to the atmosphere, are considered. 

The term membrane fouling is used to describe a long term flux decline caused by the interactions between retained particles and the membrane surface and/or membrane pores. It may occur due to a concentration polarization layer development over the membrane surface, the formation of a cake layer and/or a blockage of the membrane pores. 

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