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| Chamroux, S.; Boucher, G.. |
| Chemical and Biological evolution of sediments in closed circuit : I. Nitrogen and bacteria. A series of well controlled sea water closed circuit sand filters allowed the study of chemical and biological regulation processes in the sediment. Bacteria, Nitrogen chemistry and meiofauna were mainly investigated. The evolution of the different forms of nitrogen is rather similar, whatever the organic matter flow in the sediment. As long as the amount of organic input works as limiting factor, bacteria densities are proportional to its flow. No correlation was found between bacteria and chemical parameters in the sand or in the water. The temperature does not seem to play a determinant part neither in the evolution of bacteria nor in the mineralization of... |
| Tipo: Text |
Palavras-chave: Circuit clos; Sédiment; Bactéries; Matière organique; Azote; Closed circuit; Sediment; Bacteria; Organic matter; Nitrogen. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00305/41652/40861.pdf |
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| Boucher, G.. |
| Chemical and Biological evolution of sediments in closed circuit : II. Effect of soluble organic matter input on meiofauna in polytrophic systems. The effect on meiofauna of the input of soluble organic matter in closed circuit sand filters was followed during two years for an oligotrophic, a mesotrophic and an eutrophic tank, and during one year for an atrophic tank. In the case of no input, the density, biomass and species richness of nematodes decreases even if equitability remains constant. Oligotrophy maintains the stability and diversity. Mesotrophy changes the community composition by species succession. Eutrophy allows biomass increase, due to one dominant species. |
| Tipo: Text |
Palavras-chave: Circuit clos; Matière organique; Meiofaune; Closed circuit; Organic matter; Meiofauna. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00305/41653/40862.pdf |
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| Mevel, Genevieve. |
| Prawns (Panaeus japonicus) were rearing during more than nine months in experimental closed circuit tanks. In such systems the nitrite appearance is related to the normal nitrification process and to oxygen deficiency. Above a given level, nitrite causes the death of prawns. The soluble oxygen concentration and, thus, nitrite level in the water appears as the main factor for a successful development of prawns in closed circuit tanks. In these conditions, the growth rate of the prawns is relatively low (9g/per individual in seven months). Never theless, such a system allows a load of some 600 g prawns per m2. |
| Tipo: Text |
Palavras-chave: Circuit clos; Nitrification; Peneide; Closed circuit; Nitrification; Peneide. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00305/41655/40864.pdf |
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| Chamroux, S.; Boucher, G.. |
| The evolution of nitrogen content in experimental closed circuit ¿and filters was followed, each tank being fed with different quantities of soluble organic matter. According to the trophic conditions, two types of metabolism could be observed : - a loss of nitrogen (denitrification), reaching almost 90% of the nitrogen input in eutrophic conditions, and close to 35% in mesotrophic conditions. - a gain in nitrogen (fixation), a predominant metabolism in oligotrophic and eutrophic conditions. Nitrogen retention in the sediment increases slightly with the organic matter input, but no proportionality could be established. It seems that the sediment, by its bacterial metabolisms, regulates its own organic matter richness. |
| Tipo: Text |
Palavras-chave: Circuit clos; S; Bilan azoté; Closed circuit; Sediment; Nitrogen balance. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00305/41654/40863.pdf |
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