Aulacoseira granulata

Fig 3 Images of phytoplankton cells from the Ebro river obtained by means of epifluorescence microscopy and scanning electron microscopy. Images correspond to the species Pediastrum duplex (a), Aulacoseira granulata (b), Stephanodiscus cf. neoastraea (c), Cyclotella meneghini-nana (d), Skeletonema potamos (e), and Thalassiosira weissflogii (f)... 

Differences in chlorophyll concentrations between present and past records in the lower part of the Ebro do not correspond with significant changes in the distribution of phytoplankton assemblages. The general trends in the distribution of phytoplankton communities appear to be consistent with those reported in previous surveys, at least in the lower part of the river. Centric diatoms such as Aulacoseira granulata, Cyclotella sp. and Stephanodiscus sp. were dominant in autumn, spring, and early summer 1989-1990, while Scenedesmus sp., Coelastrum sp., and Pediastrum sp. were most abundant in the summer of that period [7]. 

Figure 2 Representative micrograph of the elaborate biosilica structures of chatom Aulacoseira granulata. (Bar = 1 J,m.)...

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