Effect Of Phosphorus And Iron On The Growth Of Red Tide Microalgae, Cryptomonas Sp.

Following the rapid development of economy, the discharge of industrial and agricultural wastewater and domestic sewage in cities are increasing, and the eutrophication in coastal sea area becomes to be worse. As a result, Red tide bursts out more and more frequently, and it has been a serious global problem of ocean environment. As the main matter leading to Red tide, ocean phytoplankton has been a focus of researches.In our studies, Cryptomonas sp. was chosen as the model alga. We discussed the interaction effects of phosphorus and iron on algous growth in the way of marine chemistry. And the main results we got are as follows:1.Different concentrations of phosphorus and iron in the medium, and adding EDTA or not do little effect on cellular shape of Cryptomonas sp.. And the cell size and phosphorus concentration inside are both diminishing along with the increasing of phosphorus concentration in the medium.2. Adding EDTA to the medium will be propitious to absorbing of iron.3. Not only phosphorus and iron, but also the interaction effects of them have extremely obvious influence to the growth of Cryptomonas sp.. And the optimization of phosphorus and iron concentrations to Cryptomonas sp. will be 50μmol/L phosphorus and 50nmol/L iron.4. Without phosphorus and iron limits, the biomass of Cryptomonas sp. has a high positive correlation with the ratio of phosphorus to iron in the medium. The biomass will rise up along with the increasing of phosphorus concentration, but drop down along with the increasing of iron concentration.5. When phosphorus concentration increases, the consumption of iron in the medium presents a parabola trend. The maximum appears at the zones of abundant phosphorus. But the variety trend of its using rate is opposite to the consumption.6. The saturation spot of light to Cryptomonas sp. is between 7000 to 10000 Lux. With the same culture time, the consumption of iron in the medium will rise up along with the increasing of light intensity, but the consumption of phosphorus will drop down along with the increasing of light intensity.