Amphora normanii

In the Eastern basin, 14 species of Bacillariophyta were found the dominant species were Amphora normanii, N. fonticola, Navicula spp., and Nitzschia communis (32, 18, 22, and 10% of total alga number, respectively). Chlorophyta was represented by only unidentified species. The total number of phytoplankton was 0.9 X 10 cells 1 and the biomass was 93 pg C... 

St. Al-6 38 m 105.56 ppt 2.75°C Nitzschia fonticola, Phytodinium cf. simplex Amphora normanii Amorphous bottom ... 

Table 12 Depth stratification of species Amphora normanii, A. proteus, Phytodinium cf. simplex, Surirella fastuosa and Naviculaphyllepta in the Channel in August 2004 and in October 2005 (Pi species fraction to the total assemblage)... 

Depth, m Salinity, ppt Temperature, °C Amphora normanii Amphora proteus Navicula phyllepta Phytodinium cf. simplex Surirella fastuosa... 

Table 13 Depth stratification of species Amphora normanii and A. proteus with salinity and tem-...

Fig. 11 Abundance of Phytodinium cf. simplex and Amphora normanii at different water depth and stations. Pi (a) species fraction to the total assemblage (1 -Amphora normanii, the Channel, 2 - A. normanii. Eastern basin, 3 - A. normanii, Western basin, 4 - Ph. cf. simplex, the Strait, 5 - Ph. cf. simplex. Eastern basin, 6 - Ph. cf. simplex. Western basin) (b) total contribution of Amphora spp., representatives of the eastern hyperhaline assemblage, at different depths and different sites, August 2004...

Fig. 12 Eastern species, observed in August 2004 (a) Amphora normanii, (b) Amphora dusenii, (c) Amphora veneta, (d) Amphora cymbifera, (e) Amphora proteus...

At 5 m water depth, the deepest in the Channel, the algal coenosis was dominated by A. normanii (19.1%), S. fastuosa (10.8%) and Tryblionella punctata (7.6%) (Table 13). The total contribution of Amphora species was reduced to half of its abundance in shallow water (31.8%) (Table 13). The assemblage exhibited a... 

The relative abundances of Amphora proteus and A. normanii at different depths did not exceed 1 % (2004) in the Western basin. Moreover, their contribution to the assemblage decreased gradually with depth (Table 13). In the channel, A. normanii occurred at most stations and was most abundant at shallow depth (0.1-0.2 m), but its abundance decreased with depth (in three steps) (Fig. 11). Sites with Amphora species in the different shallow areas, namely in the channel and at the outlet to the Eastern basin, exhibited the highest salinity in the bottom water layer. On the basis of these observations, we consider A. normanii and A. proteus as marker species of the channel-specific enviromnent. As A. proteus was almost absent in the Eastern basin at this time (0.01%), we believe that A. normanii has adapted to the higher salinity. It occurs more abtmdantly in the Eastern basin, and is therefore considered as a marker of the high salinity conditions in the Eastern basin of the Large Aral Sea (Table 12). 

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