摘要
湖泊富营养化是世界面临的重大环境问题,磷在沉积物-水界面的循环在富营养化过程中起关键作用,因此,研究沉水植物对沉积物-水界面磷循环的作用及其机理具重要的理论和实践意义.本实验通过在水泥池中(4.0 m×7.0 m×1.5 m)种植苦草(Vallisneria natans),并采用定期更换原位上覆水的方式模拟自然状态下的水体交换,研究了沉水植物苦草从定植到生长末期沉积物中不同形态磷含量的变化,以期揭示期间苦草对沉积物中磷赋存形态的影响.结果表明,本实验条件下苦草经历了两个生长阶段,在约1个月的快速生长期内能显著降低沉积物中的总磷(TP)含量,TP含量降低了78.79 mg/kg,其中有机磷(Org-P)含量降低49.99 mg/kg,对TP降低的贡献度为62.67%,而钙结合态磷(Ca-P)比对照组减少2.20%,因此,苦草可能主要通过促进Org-P的矿化向水柱和间隙水中释放磷的方式降低沉积物中TP含量,其次苦草可促进Ca-P的分解;此外,苦草为满足植株生长,所吸收的沉积物铁结合态磷(Fe-P)和铝结合态磷(Al-P)分别为2.99和4.10 mg/kg,但苦草对沉积物中闭蓄态磷(Oc-P)含量没有显著影响.在缓慢生长阶段,苦草促进有机物的沉降以及Fe-P和Oc-P的形成,Fe-P和Oc-P含量分别增加14.82和101.53 mg/kg.苦草对Al-P的形成也略有促进作用,其含量升高7.39%.研究结果表明,苦草在不同生长阶段对沉积物中磷形态的转化以及各形态磷的迁移方向具有不同的影响.在快速生长期苦草转化吸收高活性磷,将其固定到植株体内;缓慢生长阶段则促进水体中的磷转化成沉积物中难分解态的磷,对磷的沉降表现出积极促进作用.
Lake eutrophication is a global environment problem.Phosphorus exchanging at the water-sediment interface plays a key role in eutrophication process.We cultured Vallisneria natans in a 4.0 m × 7.0 m × 1.5 m concrete tank under a natural state which water exchanges all the time by replacing overlying water frequently.Different phosphorus fractions in sediment were determined to reveal their response to V.natans from the beginning of planting to the end of growth stage.In this experiment condition,V.natans went through two growth stage and the results show that V.natans significantly reduced total phosphorus （TP） through promoting the mineralize of organophosphates （Org-P）and resolve of calcium phosphorus（Ca-P）.TP reduced 78.79 mg/kg which account for 8.44％ of initial content.Org-P reduced 49.99 mg/kg that contribute 62.67％ for decreasement of TP.On the other hand,a portion of iron/aluminum phosphorus（Fe/Al-P） were absorbed for the request of the plant growth,2.99 and 4.10 mg/kg decreased,respectively,but occluded phosphate（Oc-P）was not affected.While V.natans goown to the highest biomass,it promote settlement of organic matter and formation of Fe-P and Oc-P,increment of which were 14.82 and 101.53 mg/kg,respectively.It also resulted in a Al-P content increase of 7.39％.In a word,V.natans make the phosphorus in water transfer into sediment.The result indicates that effect of V.natans on the leading direction of phosphorus transformation varies with different growth stages.Highly reactive phosphorus was absorbed and accumulated in plant as stable fraction during rapid growth stage,while absorption capacity of sediment increased during slow growth stage,exhibiting a promoted phosphorus settlement.
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2014年第2期228-234,共7页
Journal of Lake Sciences
基金
国家大宗淡水鱼类产业技术体系项目(nycytx-49-09)
水产养殖行业专项项目(201203083)联合资助
关键词
苦草
沉水植物
沉积物
磷形态分级
有机物
Vallisneria natans
submerged plant
sediment
phosphorus fractions
organic matter
