POM export

Evidence for seasonal fluctuations in the export of sinking POM from the euphotic zone has been obtained from sediment trap studies. As shown in Figure 23.3, seasonal variations in the flux of sinking biogenic hard and soft parts are detectable even in the deep zone. Furthermore, interannual variations in POC and PIC production lead to similar shifts in the deepwater fluxes of these particles. 

Fig. 1. Model depicting nitrogen flows in a kelp bed community. Primary production by macrophytes is partitioned into particulate (POM) and dissolved (DOM) components. Filter-feeders feed on detritus consisting of POM, bacteria and animal faeces. Recycling of nitrogen via the feedback loop provided by faeces is indicated by heavy lines. Fig. la) shows the model under downwelling conditions, when phytoplankton is imported with surface water from offshore. Fig. lb) shows the model under upwelling conditions when it is assumed that phytoplankton in the upwelling water is negligible and excess detritus is exported in surface water.

Particle flux is frequently extrapolated from the measurement of new production in surface waters (Dugdale and Goeiing, 1967). Export of POM out of surface waters or into the deep sea may also be estimated directly through its collection in sediment traps (e.g., Martin et al, 1987 Anita et al, 2001). Export or sedimentation of POM may also be estimated from disequilibria between two nuclides (e.g., and " Th, and °Th and Pa) that are scavenged by particles of different degrees (Buesseler et al, 1992 Kumar et al, 1993 Francois et al, 1997). 

The magnitude of this loss is thus substantial, and comparable to flux estimates for the delivery of terrigenous OC to the oceans (Figure 1). However, while the above studies imply low burial efficiencies for fluvial POM in deltaic environments, it is uncertain whether the apparent losses of riverine POM reflect its complete mineralization or export to the ocean interior either in dissolved or particulate form (Edmond et al., 1981). Moreover, the extent of terrestrial OC export and burial from river systems that do not form deltaic deposits is less weU constrained. 

Wetlands are net exporters of POM and DOM to adjacent aquatic systems, when hydrologi-cally connected to surface flow. TOC includes both particulate and DOC. In many natural systems, approximately 90% of the TOC is accounted for in DOC (Figure 5.6). The physicochemical characteristics of DOC and its concentrations in the water leaving a wetland are influenced by vegetation type, density, soil organic matter, and the extent of abiotic and biotic degradation. 

Other outputs include harvested plant biomass and detrital export (removing the nitrogen stored in the biomass, or simply wetland outflows where nutrients are exported in water and POM leaving wetlands such as in tidal marshes or riparian wetlands). 

The only other POM producer in Europe is Zaklay Azotowe, Poland, which has production capacity of around 10,000 tpa. Around 80% of the material is exported to Western Europe. 

It is noted that 38.03 t/h HPS is produced from combustion in the boiler and 2955 kW electricity is generated via both steam turbines I and II. A total of 1606kW electricity is supplied to the POM and the POB whereas the excess of 1349kW of electricity can be exported to the grid. After CHP exported steams based on requirement of POM and POB, there is an excess of 0.60 t/h MPS that can be exported to external facilities. 

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