The influence of nitrate and phosphate concentrations on growth of diatom <I>Thalassiosira mínima</I> Gaarder, using biossays

Abstract

The influence of nitrate and phosphate concentrations on growth of diatom Thalassiosira mínima Gaarder, using biossays. The assays were realized using batch cultures of diatom Thalassiosira mínima, with different concentrations of nitrate and phosphate. The culture medium, was artificial seawater (35%.) with solutions of Conways medium and different concentrations of nitrate (0,0 to 2000,0 ug at N-NO₃/1) and nitrate (0,0 to 507,3 ug at P-PO₄/1). The results showed that Thalassiosira mínima grew better at concentrations ranging from 50,0 to 1000,0 ug at N-NO₃/1 for nitrate and 1,3 to 64,1 ug at P-PO₄/1 for phosphate. At highest concentrations from both nutrients, 2000,0 ug at N-NO₃/1 and 507,3 ug at P-PO₄/1, the growth was decreased in relation to the others.