Effects Of Pb(Ⅱ) On The Growth Of Marine Algae

With batch culture experiment, it was tested the effects of Pb(â…¡) on the growth of 8 species of marine algae(Heterosigma akashiwo Hada Chaetoceros curvisetus Skeletonema costatum (Greville) Cleves Pheodactylum tricornutum Bohlin Platymonas subcordiformis Platymonas helgolanidica Kylin var tsingtaoensis Prorocentrum micans Gymnodinium sp.).A growth model, with consideration of effects of Pb(â…¡) on the growth of marine algae was developed. And the effects of Pb(â…¡) on the growth of red-tide algae in different concentration of the nutrient were further studied.1. the effects of Pb(â…¡) on the growth of marine algaeWith batch culture experiment, it was tested the effects of Pb(â…¡) on the growth of 8 species of marine algae. The experimental results showed that higher doses of Pb(â…¡) inhibited the growth of Heterosigma akashiwo Hada Chaetoceros curvisetus Skeletonema costatum (Greville) Cleve Pheodactylum tricornutum Bohlin Platymonas subcordiformis Platymonas helgolanidica Kylin var tsingtaoensis Prorocentrum micans Gymnodinium sp . But, lower doses promoted the growth of marine algae,excluding Prorocentrummicans Gymnodinium sp .A growth model, with consideration of effect of Pb(â…¡) on the growth of marine algae, was developed by incorporating Logistic growth model with Lorentz equation and GaussAmp equation.Lorentz equation can describe the effect of Pb(â…¡) on the growth rate constant while GaussAmp equation can describe the effect of Pb(â…¡) on the final biomass of algae. It was demonstrated that the growth model showed good fitting for the experimental data and the related coefficients was 0.825~0.998 with an average of about 0.921.2. Effects of Pb (â…¡) the Growth of HAB algae at differedt concentration ofnutrientsWith batch culture experiment, it was tested the effects of Pb(â…¡)on the growthof 2 species of HAB algae at different concentration of nutrients. The results show that the 96hEC50 of Pb(â…¡) for the Chaetoceros curvisetus, Skeletonema costatum were tested 8373 2563 2307; 19217 18523 10446g-dm-3. A growth model, withconsideration of effect of Pb on the growth of marine algae, was used to describe the growth process of the HAB at the different concentration of nutrients. It was tested well.And the experimental results showed that higher doses of Pb inhibited the growth of algae,while lower doses promoted the growth of the two HAB. And the effect concentration of Pb that accelerated the growth of them with the concentration of nutrient culture increased.The maximal growth rate of two species HAB Cpb-Max(g-dm-3) ,were tested 454 218, 57; 351 194, 35g.dm-3. 3. Effects of Pb on the mean diameter of Marine AlgaeWith batch culture experiment, it was tested the effects of Pb on the diameter of 6 species of marine algae.Gauss distribution function was utilized to describe the distribution of the mean percentage of the equivalent spherical diameter of marine phytoplankton.According to the study results, it was found that Platymonas subcordiforus Heterosigma akashiwo, Hada Skeletonema costatuma Chaetoceros curvisetus have one peak,while Prorocentrummicans and Gymnodinium sp. are duplicated peaks. It can be generally described the change of the mean diameter(MD) with the time in the different concentration of Pb with the three-dimension Surfer graph. In the same of the concentration of Pb, the MD of six species was increased firstly,and then decreased with the time. But at the concentration of 10000g . dm-3,the MD of Heterosigma akashiwo Hada was increased in the growth cycle. And at the same time ,the MD of Platymonas subcordiforus Heterosigma akashiwo, Hada Skeletonema costatuma Chaetoceros curvisetus was also increased firstly,and then discreased with the concentrations while the mean diameter of Prorocentrummicans and Gymnodinium sp was decreased firstly and then increased.