摘要
Competition of three bloom-forming marine phytoplankton (diatom Skeletonema costatum, and dinoflagellates Prorocentrum minimum and Alexandrium tamarense) was studied through a series of multispecies cultures with different nitrate (NaNO 3 ) and phosphate (NaH 2 PO 4 ) levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates in nitrate and phosphate replete cultures with 10 μmol/L Na 2 SiO 3 . Under nitrate limited (8.82 μmol/L NaNO 3 ) conditions, the growth of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 μmol/L. Cell density of the two dinoflagellates only increased slightly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day 12, and then increased to 4000 cells/mL (1.5 mg/L dry biomass) at NaNO 3 concentrations between 88.2 and 882 μmol/L with limited phosphate (0.36 μmol/L NaH 2 PO 4 ) levels. In addition, P. minimum grew well with a maximal cell density of 1690-2100 cells/mL (0.5-0.6 mg/L dry biomass). Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew well under limited nitrate when growth of the dinoflagellates was near detection limits.
Competition of three bloom-forming marine phytoplankton （diatom Skeletonema costatum, and dinoflagellates Prorocentrum minimum and Alexandrium tamarense） was studied through a series of multispecies cultures with different nitrate （NaNO 3 ） and phosphate （NaH 2 PO 4 ） levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates in nitrate and phosphate replete cultures with 10 μmol/L Na 2 SiO 3 . Under nitrate limited （8.82 μmol/L NaNO 3 ） conditions, the growth of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 μmol/L. Cell density of the two dinoflagellates only increased slightly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day 12, and then increased to 4000 cells/mL （1.5 mg/L dry biomass） at NaNO 3 concentrations between 88.2 and 882 μmol/L with limited phosphate （0.36 μmol/L NaH 2 PO 4 ） levels. In addition, P. minimum grew well with a maximal cell density of 1690–2100 cells/mL （0.5–0.6 mg/L dry biomass）. Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew well under limited nitrate when growth of the dinoflagellates was near detection limits.
基金
supported by the National Key Basic Re-search Special Foundation of China(No.2001CB409706)
