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The Lagoa de Araruama is a hypersaline ecosystem inhabited by distinct fish species, either permanently or during their reproductive season. Over recent years, some significant environmental changes have been observed in this ecosystem related to the sewage runoff, as salinity decrease (from 64 to 41 psu during the last 40 years) and nutrients increase. As both changes are thought to affect the ichthyoplankton assemblage, the present study aimed to evaluate all the potential relationships between salinity disruption and fish larvae distribution. Ichtyoplankton samples were collected monthly from January 2010 to March 2011 at eight sites in Araruama Lagoon by means of a WP2 plankton net equipped with a flowmeter. During this period, low egg densities were coincident with high salinity regions, suggesting that adults are avoiding to release their eggs under less favorable environmental conditions to the larvae. The uneven distribution of eggs and larvae inside the lagoon, as revealed by both spatial and temporal analyses lead us to suggest that changes in salinity have influenced the reproductive rhythms of those fish species that depend upon the Lagoa de Araruama.

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ResumeUn clone de cyanobacterie chroococcale (Aphanothece sp.) isole des salines de Santa Pola (Espagne) a ete etudie d'un point de vue morphologique et ultrastructural. De plus, outre la chlorophylle a, la phycocyanine et Pallophycocyanine, une analyse par HPLC a permis de separer 10 caroteno'ides: myxoxanthophylles, nostoxanthine, caloxanthine, zeaxanthine, cryptoxanthine, echinenone, epoxydes de ß-carotene et ß-carotene. Ce dernier pigment forme ä lui seul 70-80% de la masse totale des caroteno'ides.Uimpact de la salinite (de 0,6 M ä 3 M de NaCl), de la temperature (de 25 °C ä 40 °C) et leur interaction sur la croissance de cette chroococcale ont ete etudies. C'est une algue eurytherme et halotolerante, s'adaptant rapidement aux stress causes par ces 2 facteurs. La croissance est relativement lente, le temps minimum de generation observe est de 29,7 h et a ete obtenu pour une salinite de 2 M et une temperature de 40 °C; on a observe une etroite interdependance entre ces deux facteurs. Salinite et temporature n'ont pas engendre de variations importantes ni dans la composition pigmentaire (chl a et caroteno'ides varient de fa?on identique), ni dans la taille des cellules (correlation hautement significative entre longueur et largeur). On observe des variations importantes dans la concentration protoinique et glucidique des cellules, mais sans relation previsible avec la temperature et la salinite.Cette souche pourrait presenter un interet en aquiculture intensive de par sa richesse en proteines et polysaccharides. Abstract Interaction of Salinity and Temperature on Morphology, Growth and Cell Composition of a Halotolerant Cyanobacterium (Aphanothece sp.)A strain of Aphanothece sp., a chroococcalian cyanobacterium, was isolated from Santa Pola Salt Marsh (Spain) and studies were carried out concerning its morphological and ultrastructural aspects. In addition to the following light-harvesting pigments, chlorophyll a, phycocyanin and allophycocyanin, ten algal carotenoids were identified by HPLC: mixoxanthophylls, nostoxanthin, caloxanthin, zeaxanthin, cryptoxanthin, echinenone, several derivatives of ß-earotene containing epoxidic functions and ß-carotene. The latter pigment accounted for 70 to 80% of total carotenoids. 318 Berland et al: Interaction salinite-temperature sur Aphanothece sp.The effect of salinity (0,6 to 3 M NaCl) on the growth of this alga was investigated at different temperatures (25 °C to 40 °C). The results indicate that this cyanobacteria is an eurythermal and halotolerant organism exhibiting rapid adaptation to salinity and temperature changes. Aphanothece sp. showed a low relative growth rate with a minimum doubling time of 29.7 h at 2 M NaCl and 40 °C. No significant influence of the different salt concentations and temperatures on pigmentation (similar changes in chla and carotenoid contents) and cell size (highly significant correlation between length and breadth) was found in Aphanothece sp. Variations in carbohydrate and protein cell contents showed no evident relationship to salinity...