Organic Matter Production Side

In the preceding discussions, we assumed labile DOC and DON to be produced at rates y/c and y/N, respectively, without discussing their sources and how the production rate and the composition of the produced material would be expected to vary with food web structure. The important differences among different models can be illustrated by some examples. One potential model is that DOC production is an overflow mechanism occurring in mineral-nutrient-limited phytoplankton not able to use the photo-synthetically produced organic carbon for biomass production due to lack 

In the present situation, it is a rather unattractive idea to try to construct a detailed mathematical description of all the suggested mechanisms for DOM production. The expectation would be that this could rapidly lead into a jungle of poorly supported hypotheses, poorly quantified parameters, and a dependence on species composition, which is another poorly defined aspect of the present models. A possible alternative would be to explore the use of more aggregated descriptions. Two simple alternative hypotheses of this kind would be that production is either (1) proportional to plankton 

FIGURE 4 Integrated model for bacterial production illustrating qualitatively the suggested proportionality with the square of total plankton biomass for C-limited bacteria, and proportionality with the square of ciliate biomass for mineral-nutrient-limited bacteria. In this model, C-limited growth occurs for food web structures with a high ciliate total plankton biomass. 

This work was financed by EU contract DOMAINE EVK3-CT2000-00034. 

Billen, G., and A. Fontigny. 1987. Dynamics of a Phaeocystis dominated spring bloom in Belgian coastal waters. II. Bacterioplankton dynamics. Marine Ecology Progress Series 37 249-257. 

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Photocatalysis by transition metals shows an effective self-cleaning ability of soils and waters by the degradation and complete mineralization of the dissolved organic matter. Moreover, the oxidation processes are driven by sunlight and atmospheric oxygen and do not pollute the environment by risky side-products (see section 9.3, Chapter 9). 

On the other hand, pressure is applied in reverse osmosis to drive the solvent (water) out of the high-concentration side into the low-concentration side this facilitates de-watering insoluble species for their removal. This process produces high-quality water and concentrated refuse. It separates and removes dissolved solids, organics, pyrogens, colloidal matter, viruses, and bacteria from water in the particle range 10 4—10—2 pm. Reverse osmosis can remove up to 95%-99% of the total dissolved solids (TDS) and 99% of all bacteria. It is used for the ob-tention of drinking water from seawater and for the production of ultra pure water in various industries. 

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