Growth interactions between the dinoflagellate Levanderina fissa (=Gyrodinium instriatum) and the other three algal bloom species Skeletonema costatum (Bacillariophyceae), Prorocentrum micans (Dinophyceae), and Chatto...Growth interactions between the dinoflagellate Levanderina fissa (=Gyrodinium instriatum) and the other three algal bloom species Skeletonema costatum (Bacillariophyceae), Prorocentrum micans (Dinophyceae), and Chattonella marina (Raphido- phyceae) were studied using bi- or tri-algal co-cultures under laboratory conditions. The Lotka-Volterra model was applied to esti- mate the interspecific competition between them. Results showed that the growth of L. fissa was significantly suppressed in both bi-algal and tri-algal cultures, and the maximum cell densities in co-cultures were only between 21% and 69% of that in mono-cul- ture. L. fissa outcompeted P. micans;however, its effects on S. costatum and C. marina were generally less than the effects of their intraspecific competitions based on the competition coefficients. Contrarily, the inhibitory effects of S. costatum and C. marina on L. fissa were much greater. S. costatum outcompeted the other three species in all co-cultures, and its competition coefficients on the other species were more than 10000 times higher than the opposite. The growth of C. marina was suppressed by S. costatum;how- ever, it outcompeted L. fissa and P. micans. The growth of P. micans was most strongly inhibited in co-cultures, and the maximum cell densities in co-cultures were less than 15% of that in mono-species culture. The results suggested that L. fissa had few advan- tages in the interspecific competition. The adaptation to low salinity and the utilization of organic phosphorus might be the important reasons for L. fissa to take the competitive predominance in brackish estuarine environments.展开更多
Effects of nitrogen(N) and phosphorus(P) from different sources and at different concentrations on the growth of Levanderina fissa(= Gyrodinium instriatum) were studied in laboratory conditions. The findings might exp...Effects of nitrogen(N) and phosphorus(P) from different sources and at different concentrations on the growth of Levanderina fissa(= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate(μmax) and half-saturation nutrient concentration(KS) were 0.37 divisions/d and 8.49 μmol L^(-1) for N, and 0.39 divisions/d and 1.99 μmol L^(-1) for P, respectively. Based on KS values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N(DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P(DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 41476132)
文摘Growth interactions between the dinoflagellate Levanderina fissa (=Gyrodinium instriatum) and the other three algal bloom species Skeletonema costatum (Bacillariophyceae), Prorocentrum micans (Dinophyceae), and Chattonella marina (Raphido- phyceae) were studied using bi- or tri-algal co-cultures under laboratory conditions. The Lotka-Volterra model was applied to esti- mate the interspecific competition between them. Results showed that the growth of L. fissa was significantly suppressed in both bi-algal and tri-algal cultures, and the maximum cell densities in co-cultures were only between 21% and 69% of that in mono-cul- ture. L. fissa outcompeted P. micans;however, its effects on S. costatum and C. marina were generally less than the effects of their intraspecific competitions based on the competition coefficients. Contrarily, the inhibitory effects of S. costatum and C. marina on L. fissa were much greater. S. costatum outcompeted the other three species in all co-cultures, and its competition coefficients on the other species were more than 10000 times higher than the opposite. The growth of C. marina was suppressed by S. costatum;how- ever, it outcompeted L. fissa and P. micans. The growth of P. micans was most strongly inhibited in co-cultures, and the maximum cell densities in co-cultures were less than 15% of that in mono-species culture. The results suggested that L. fissa had few advan- tages in the interspecific competition. The adaptation to low salinity and the utilization of organic phosphorus might be the important reasons for L. fissa to take the competitive predominance in brackish estuarine environments.
基金financially supported by the National Natural Science Foundation of China(Nos.41276154,41476132)
文摘Effects of nitrogen(N) and phosphorus(P) from different sources and at different concentrations on the growth of Levanderina fissa(= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate(μmax) and half-saturation nutrient concentration(KS) were 0.37 divisions/d and 8.49 μmol L^(-1) for N, and 0.39 divisions/d and 1.99 μmol L^(-1) for P, respectively. Based on KS values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N(DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P(DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary.
