Développement “printanier” de la diatomée Rhizosolenia delicatula près de Roscoff

Abstract Rhizosolenia delicatula (Cleve) is not very often quantitatively recorded, although frequently mentioned in plankton investigations in European waters. Recent studies at Roscoff (France) place it among the dominant species in the seasonal cycle. R. delicatula is present most of the year. It... flowered in May/June every year from 1962 to 1966 at a rate of cell division in accordance with exponential growth. This bloom falls in with the main seasonal bloom of phytoplankton as cell numbers and chlorophyll a. Detailed study of the growth in 1966 shows that horizontal transport exists due to spring and neap tide alternations. Highest records of cell numbers coincide with highest tidal coefficients. By comparing environmental conditions each year at the time growth takes place, optimal growth conditions were defined as follows: temperature 12° to 13°C, salinity 35‰, light 0.07 to 0.09 cal.g/cm2/min. Phosphate is not a limiting factor. After exponential growth, the species seems to be controlled by grazing. R. delicatula has a definite place in both the hydrographical cycle and plancton succession. It is the first noticeable species of the summer diatom suecession. R. fragilissima precedes R. delicatula in the succession, but has no such successful development. These two spec Ausführliche Beschreibung Beschreibung ausblenden

1. Person:	Grall, J. -R.
Quelle:	in Marine biology : international journal on life in oceans and coastal waters Vol. 16 (1972), p. 41-48 Weitere Artikel
Format:	Online-Artikel
Sprache:	French
Veröffentlicht:	1972
Beschreibung:	Online-Ressource
Online Zugang:	Online
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Anmerkung:	Copyright: Copyright 1972 Springer-Verlag