Different growth pattern of Heterosigma akashiwo with salinity and micronutrients gradient by geology

H. akashiwo, one of famous HABs (harmful algal blooms species), blooms are characterized by a high growth rate. Especially, rapid growth is important in dense bloom formation (Bearon et al., 2006). Physicochemical factors, such as water temperature, salinity, light intensity and nutrients, strongly affect bloom formation (Tilman et al. 1982; Erga and Heimdal 1984; Smayda 1998; Diehl et al. 2002). Thus, we report the comparisons of different geological originated H. akashiwo strain for influence on salinity, light intensity and micronutrient. For this study, physiological characteristic of vegetative strain from cyst (HYM06HA) and the other strains from southern eastern coastal water in Korea (NFHTS-AK-1) and Ling Island Sound, USA (CCMP 452) are compared. To compare the different geological difference, we estimate the maximum growth rates during the exponential phase. The CCMP 452 strain was grows well at all salinity gradients except extreme condition like 5 and 40 psu. Uniquely, the optimal growth rate conditions for salinity of Korean strains were 10 and from 25 to 30 psu. It seems to be the bimodal distribution. The NFHTS-AK-1 was shown maximum growth rate at 50 µmol photons m-2 s-1 and HYM06HA was 125 µmol photons m-2 s-1. CCMP 452 grows well from 50 µmol photons m-2 s-1. Phosphate source affected a lot to the growth rate of Korean strains. In contrast the strain, wh temperature, salinity, light intensity and nutrients, strongly affect bloom formation (Tilman et al. 1982; Erga and Heimdal 1984; Smayda 1998; Diehl et al. 2002). Thus, we report the comparisons of different geological originated H. akashiwo strain for influence on salinity, light intensity and micronutrient. For this study, physiological characteristic of vegetative strain from cyst (HYM06HA) and the other strains from southern eastern coastal water in Korea (NFHTS-AK-1) and Ling Island Sound, USA (CCMP 452) are compared. To compare the dif1

The population dynamics of phytoplankton under low temperature period at East Sea in Korea.

Phytoplankton under 20 ㎛ plankton at the East sea in Korea because the ‘East sea’ has similar characteristics of ocean. Especially, the biomass of 20 ㎛ plankton, and 20 ㎛ plankton and S type was most dominant for 20 ㎛ plankton, and <20 ㎛ phytoplankton divided by type, F(filament), O(oval), OF(oval & flagella), R(rod), S(spherical) type. Water temperature were ranged from 8.24∼13.05 ℃, salinity were ranged from 26.25∼35.35 PSU during sampling periods. The phytoplankton abundances were 1.94×105∼4.36×106 cells L-1 and the biomass of <20 ㎛ plankton we1

Phytoplankton composition under low temperature period at East Sea in Korea

Nano and picoplankton (20 ㎛ plankton were investigated at the East sea because the ‘East sea’ has similar characteristics of ocean. Especially, the biomass of 20 ㎛ plankton, and 20 ㎛ plankton and S type was most dominant for 20 ㎛ plankton, and <20 ㎛ phytoplankton divided by type, F(filament), O(oval), OF(oval & flagella), R(rod), S(spherical) type. Water temperature were ranged from 8.24∼13.05 ℃, salinity were ranged from 26.25∼35.35 PSU during sampling periods. The phytoplankton abundances were 1.94×105∼4.36×106 cells L-1 and the biomass of <201

The evaluation for the fast cell division with non-uniform cell cycles

To obtain a better understanding of the bloom development mechanism in the aquatic systems, accurate estimates of species-specific in situ growth rates are needed for the migration and bloom mechanisms of red tide. The harmful algal blooms caused by fast cell division of microorganisms. To estimate accurate in situ growth rate of H. akashiwo which has non-uniform and irregular cell cycles, we modified equation based on the cell cycle and calculated the in situ growth rate to describe their bloom developmental process in nature. Sampling was conducted every three hours from 15:00 on August 2 to 7:00 on August 4, 2006 in Pohang Bay, Korea. DNA amounts in the H. akashiwo were measured with a flow cytometer following tyramide signal amplification-fluorescence in situ hybridization (TSA-FISH). During the first night, the percentage of G1 phase cells decreased from 15:00 to 19:00 and increased until 22:00. It dramatically decreased from 22:00 on 2 August and increased from 7:00 to10:00 on 3 August. These results suggest the capability of dividing more than once d-1. Similar results were obtained the following night but division did not occur twice during the second night. Based on the results, in situ growth rates ranged from 0.31 to 0.53 d-1. We conclude that, with the aid of this newly derived equation, the blooming formation by fast cell division could estimate more accurate.oms caused by fast cell division of microorganisms. To estimate accurate in situ growth rate of H. akashiwo which has non-uniform and irregular cell cycles, we modified equation based on the cell cycle and calculated the in situ growth rate to describe their bloom developmental process in nature. Sampling was conducted every three hours from 15:00 on August 2 to 7:00 on August 4, 2006 in Pohang Bay, Korea. DNA amounts in the H. akashiwo were measured with a flow cytometer following tyramide signal amplification-fluorescence in situ hybridization (TSA-FISH). D1