底泥悬浮对营养盐释放和水华生长影响的模拟

EFFECTS OF EXPERIMENTAL SEDIMENT SUSPENSION ON THE NUTRIENTS RELEASE AND GROWTH OF ALGAL BLOOM

通过室内模拟实验研究了扰动引起的太湖底泥悬浮对水体氮磷营养盐和蓝藻水华的影响,其中底泥和上覆水均来自太湖,扰动强度以悬浮物浓度表示。实验监测了底泥扰动过程中以及扰动停止后48h之内水体氮磷营养盐和叶绿素a的变化,采样间隔为6h。实验结果表明,扰动明显增加了水体中总氮、总磷、活性磷等含量,但是可溶性无机氮的增加不明显,叶绿素a含量没有出现明显的增长。水华没有出现明显增长很可能是氮限制的原因。由此推测太湖一次风浪扰动过程引起的底泥营养盐释放不一定就能够加剧蓝藻水华的暴发。底泥中释放的营养盐对蓝藻水华的影响需要进一步研究。

An indoor experiment was conducted to study the effect of sediment suspension on the release of nitrogen（N）,phosphorus（P） and proliferation of cyanobacteria bloom,in which the sediment and overlying water were all from Lake Taihu.The disturbance intensity was expressed as suspended substance（SS）.The concentrations of N,P and chlorophyll-a（Chl-a） were measured during the process of disturbance and the following 48 hours after the disturbance stopped,and the sampling interval was 6 hours.The results showed that the disturbance improved the total nitrogen,total phosphorus and soluble reactive phosphorus significantly,however,there was no significant increase of dissolved inorganic nitrogen（NO-3-N,NO-2-N and NH＋4-N）,neither did the Chl-a.Nitrogen limitation may be the reason of no increase of the algal bloom.It showed that sediment suspension promoted the release of N and P,but those nutrients not necessarily improved the cyanobacteria bloom.Further study on the effects of nutrients released from sediment to cyanobacteria bloom is necessary.