Free Polyamines In Frequent HAB Area Of The East China Sea In 2010 And A Preliminary Exploration On Its Possible Role In The Red Tide Succession

Based on the survey of MC2010-01 and MC2010-02 and alage cultivation experiments, we used HPLC measured the contents of free free 2-Phenylethylamine, putrescine, spermidine, and spermine in waters collected in East China Sea in April, May, June and October, and Changes in intracellular and extracellular free putrescine, spermidine, and spermine during the growth cycle of Skeletonema costatum were also studied.Putrescine and spermidine were the main intracellular free polyamines detected in Skeletonema costatum. The intracellular concentration of free polyamines kept increasing during the growth cycle and the ratio of putrescine to spermidine increased with cell density. Changes in the ratios of spermine/spermidine in Skeletonema costatum, however, occurred before changes in cell density, suggesting that polyamines can regulate cell growth and replication. Putrescine was the most abundant free polyamine in the culture medium, followed by spermidine and spermine. Changes to the media polyamines contents implied that Skeletonema costatum could absorb free polyamines from the culture solution as well as release free polyamines into the medium during different growth periods, especially during the decline phase. These results suggest that masses of dead algae in the population decline phase would release abundant free polyamines into the environment.Spermine and putrescine were the main polyamine in seawater in April and May and the concentration of spermidine was the lowest. Most polyamines concentrations were high where the red tide occurred. The concentrations of free putrescine, spermidine and spermine in May were all lower than that of in April and vertical distributions were different, but the composition proportion of polyamines did not change significantly. The horizontal distribution of putrescine and spermine on May were the same to that of chlorophyll a. Putrescine and spermine might have an important role in the red tide succession. The contents of salinity, NO3-N, NH4-N and PO4-P all got influences on the growth of the alage, which induces changes of free polyamines contents in seawater.Putrescine was the main polyamine in seawater in June with the concentration changed from 5.16 nmol/L to 62.28 nmol/L, accounting for 62%±15% of overall. Spermidine was the lowest with the concentration changed from undetectable to 6.98 nmol/L, accounting for 6%±5% of overall. Most polyamines concentrations were high near the Changjiang River Estuary and the Hangzhou Bay. Higher concentrations of 2-Phenylethylamine, spermidine, and spermine in middle layer than in bottom layer, and higher contents of putrescine in bottom layer than in surface layer were detcted in most sections. Polyamine concentrations were higher where the red tide of Noctiluca scintillans occurred.Spermidine and putrescine was the main polyamine in seawater in October, accounting for 43%±15% and 37%±15% of overall. Most polyamines concentrations were high near the Hangzhou Bay and Changjiang River Estuary. Higher concentrations of 2-Phenylethylamine in middle layer than in bottom layer, and higher contents of putrescine in surface layer than in middle layer, and higher contents of spermidine in bottom layer than in surface layer were detcted in most sections. Spermine got the highest contents in Middle layers in most sections.