桓仁水库初级生产力和限制性营养盐研究

2018年4月10日、6月11日、8月14日在桓仁水库的上游(江南九队)、中游(砬砬岗子)和下游(泗河大地)3个站位用500 mL具塞磨口瓶盛装采水器采集的水库水样,进行限制性营养盐原位试验,同时测定水中溶解氧和初级生产力,并检测分析水体理化指标,以查明辽宁桓仁水库氮磷分布、营养盐限制和初级生产力状况,保护桓仁水库生态系统的结构和功能完整性。试验结果显示,营养盐加富试验中,0.5 mg/mL氮+0.3 mg/mL磷的添加组可显著提高水体中的溶解氧水平(P<0.05);上游和中游氮磷比为2∶1、下游氮磷比为4∶1可显著提高水体中的溶解氧水平(P<0.05);初级生产力随季节变化特征明显,原始P/R系数均小于试验组。根据试验结果分析得知,桓仁水库营养盐限制因素受季节变化的影响显著,具有氮、磷双限制等特征;根据初级生产力判断桓仁水库为自养代谢型水体。

Primary Productivity and Restricted Nutrients in Huanren Reservoir,Liaoning Province

The restricted nutrients and physical and chemical indicators of water were determined in situ in water samples collected at three sampling sites in the upstream(Jiangnanjiudui),middle(Lalagangzi)and downstream(Sihedadi)of Huanren Reservoir,Liaoning Province,on April 10,June 11,and August 14,2018 to understand the nitrogen and phosphorus distribution,nutrient limitation and primary productivity of Huanren Reservoir in Liaoning,and to protect the structure and functional integrity of ecosystem in Huanren Reservoir.Significant increase in dissolved oxygen levels in water was observed at 0.5 mg/mL of nitrogen and 0.3 mg/mL of phosphorus,and N/P value of 2∶1,and N/P value of 4∶1 in downstream was in upstream and middle reaches in nutrient enrichment experiment(P<0.05).It was found that the primary productivity was changed significantly with season,with the lower original P/R coefficient than that in experimental group.It is concluded that nutrient limiting factors in Huanren Reservoir are significantly affected by seasonal variation,with dual restrictions such as nitrogen and phosphorus.According to primary productivity,Huanren Reservoir is a self nourishment metabolic water body.