normanii's auxospores carried out in the laboratory (Vidal & Galan, 1999) showed that at 2.7 PSU salinities auxospores did not form as they started to form at 10 PSU (61 [+ or--] 14.4 auxospores [ml.sup.-1] [day.sup.-1]) and had an optimal formation at 20 PSU (75 [+ or--] 9.7 auxospores [ml.sup.-1] [day.sup.-1]) (Figure 3).
It is through these gradients, sexual reproduction, and the formation of the auxospores that A.
The formation of auxospores has been also observed in the lab for Coscinodiscus granii Gough when salinity increased to 900 and 950 mOsmol (ca.28-30 PSU) (Schmid, 1994), as well as for C.
normanii small cells over large ones in these samples (Table 2, Figure 4) and the high cell concentrations (Table 3) might be a sign of a limited possibility of cells to form auxospores and large cells probably as a result of a long-lasting period of very low salinity.
normanii reproduces sexually and generates auxospores and, thus, cell diameters are greater than >40 [micro]m.
Production of male gametes and auxospores in the centric diatoms Cyclotella meneghiniana and C.
Production of male gametes and auxospores in a polymorphic clone of the centric diatom Cyclotella.
Auxospores formation (Aux/l) according to variation in salinity at different stations: Sevilla, Barra, Centro and Cano Grande in Cienaga Grande de Santa Marta, 1987.