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| Maestrini, S; Robert, J. |
| Microalgal population of oyster ponds is dominated by several tychobenthic diatoms which provide a very good food to grow oysters. The mechanisms which allow them to dominate have been put under research. H.P.L.C. analysis demonstrated 17 amino acids amounted 10-17% of total DON, i.e. 0.6-11.5 mu g-at/l nitrogen. Serin and glycin were the most abundant. None of the substances was related to the presence of oyster. Glutamic acid, alanin and ornithin concentrations showed the greatest variations; they are suspected to play the major role as nutrient source. Screening of nutritional capabilities of ten local isolates of micro-algae to use 42 organic substances as sole source of nitrogen, demonstrated urea, glutamic acid and hypoxanthin are assimilated by all... |
| Tipo: Text |
Palavras-chave: Bacillariophyceae; Bivalvia; Biomass; Pond culture; Algal settlements; Oyster culture; Nutritive value; Dissolved organic nitrogen. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-1531.pdf |
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| Maestrini, S; Rochet, M; Legendre, L; Demers, S. |
| Nutrient analyses were done in melted ice, frazil and sea water of the upper part of the water column, where as major constitutive elements of micro-algae were analysed. Measurements of nutrient uptake were carried out with frazil algae incubated at -1.5 degree C in a field incubator. Differential-enrichment bioassays and mean N/P ratio (5.9) demonstrated that actual growth of the cultures was nutrient-limited. Nitrogen governed the algal yield when illumination and grazing allowed the microalgae to grow. It concluded that the epontic dynamics is not only controlled from above, by the seasonal (climatic) changes in light intensity as generally assumed, but also from below, by the short-term (hydrodynamic) events of vertical mixing that replenish the... |
| Tipo: Text |
Palavras-chave: Nutritive value; Growth; Food absorption; Algae; Ice water interface; Biomass; Nutrients (mineral). |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-1533.pdf |
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| Berland, B; Burlakova, Z; Georgieva, L; Izmestieva, M; Kholodov, V; Krupatkina, D; Maestrini, S; Zaika, V. |
| Phytoplankton biomass has been studied in the Levant Sea (Eastern Mediterranean) during summer 1983 in order to picture its vertical distribution as well as its limitation mechanisms. Biological tests carried out on the natural populations of the Basin show that P is the first biomass-limiting element and that N is the second. The simultaneous input of P and N, however, is not sufficient to induce growth; this suggests that Mn has an essential role in the phytoplanktonic growth in this ultra-oligotrophic water. Discussion deals with the significance of the deep chlorophyll a maximum and with the physiological processes allowing it to last. |
| Tipo: Text |
Palavras-chave: MED; Eastern Mediterranean Nitrogen Phosphorus Chlorophylls Biomass Temperature effects Nutrients (mineral) Vertical distribution Limiting factors Phytoplankton. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-1519.pdf |
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