[Variation of nitrogen and phosphorus concentration in water-sediment system and influence of overlying water on the algae growth].

The effect of biosidal treatment of initial sediment,addition of inhibitor and addition of phosphorus on the transform of nitrogen and phosphorus in the sediment-water simulative system were studied.S.quadricaudain was cultured in overlying waters took from the above experiment sets when the above experiment completed.The result indicated that,biosidal treatment enhanced the concentration of TP while there was no obvious effect on N.The TP,DTP and TN concentrations were closely between inhibitor addition set and the control set in the sediment-water simulative system but the content of NO~-_3-N of the set with inhibitor addition reached 19.2(mg·L~(-1)),which was much higher than that of the control set.The sediment significantly adsorbed the P added to the system,and the content of TP decreased when the system reached balance.Algae biomass of the biosidal treatment set was higher than that of the control set,and the main cause was sterilizer leaded to higher concentration of TP of the biosidal treatment set.The highest Algae biomass of the group with inhibitor(224.5×10~4(unit·L~(-1))) was much higher than that of the control set(26×10~4(unit·L~(-1)),) and that was 5～10 times than that of other sets(sterilized set 22.5×10~4 unit·L~(-1),set with P added 38.5×10~4(unit·L~(-1)).) Inhibitor restrained the microorganism from using some nutrition which was important to alga's growth.At the beginning,the addition of P had no remarkable effect on the alga growth,but along with the experiment,the alga of the P addition set adapted to the environment and algae biomass exceed that of the control set.The increase of biological bioavailable phosphorus of sediment in biosidal treatment set and addition of inhibitor sets were caused by the increase of algae biomass and thus the increase of liable organic phosphorus.