| 引用本文: | 阮景荣,戎克文,王少梅.微型生态系统中鲢、鳙下行影响的实验研究——2.营养物水平.湖泊科学,1995,7(4):334-340. DOI:10.18307/1995.0407 |
| Ruan Jingrong,Rong Kewen,Wang Shaomei.Experimental sttudies on the top - down effects of silver carp and bighead carp in freshwater microcosms (Ⅱ):nutrient levels. J. Lake Sci.1995,7(4):334-340. DOI:10.18307/1995.0407 |
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| 摘要: |
| 鲢、鳙放养使微型生态系统的水柱氮、磷浓度和磷的分布发生了明显的变化。至实验结束时,各实验组的水柱颗粒磷、总磷和氨氮浓度都比对照组高,而正磷酸盐浓度和沉积物磷的量均低于对照组。这种变化以鳙单养系统为最大,其次是鲢、鳙混养系统,鲢单养系统的变化最小。微型生态系统中正磷酸盐浓度同浮游动、植物密度和初级生产力显著相关,氨氮浓度同所述变量之间的相关关系则多半与正磷酸盐相反。实验观测期间浮游植物密度与总磷浓度之间存在营养级联假说所预见的下行影响,实验结束时二者之间却有上行影响的趋向。根据实验观测结果认为,微型生态系统营养物(尤其是磷)水平的变动,主要是鲢、鳙的摄食改变了系统的群属结构和代谢强度的结果,同时反映了实验鱼对系统中营养物再生的影响。 |
| 关键词: 微型生态系统 鲢 鳙 营养物动态 正磷酸盐 氨氮 磷分布 |
| DOI：10.18307/1995.0407 |
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| 基金项目:国家自然科学基金资助项目(3870344) |
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| Experimental sttudies on the top - down effects of silver carp and bighead carp in freshwater microcosms (Ⅱ):nutrient levels |
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Ruan Jingrong, Rong Kewen, Wang Shaomei
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Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072
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| Abstract: |
| Stocking silver carp (Hypophlhaimichlhys molilrix) and big head carp (Arstichihys nobilis) at the density of 15 g/m3 induced obvious changes in nitrogen and phosphorus concentrations and phosphorus distribution in freshwater microcosms under relatively high nutrient loading (average P loading=1.0061 g P/(m3·day). As compared with the controls, the microcosms with fishes were characterized by higher concentrations of particulate phosphorus (PP), total phosphorus (TP) and ammonia (NH3-N), lower orthophosphate (PO4-P) concentration and smaller quantity of sediment phosphorus at the end of the experiment. Such changes were the greatest and the smallest in the microcosms containing solely bighead carp and solely silver carp (monoculture) respectively, and medium in the microcosms with both species of fish (mixed culture). It has been found that PO4-P concentration was significantly correlated with zooplankton and phytoplankton densities and primary production in the microcosms, and correlations between NH3-N concentration and the related variables were mostly in the opposite direction to those for PO4-P concentration. There was the top-down effect predicted by the trophic cascade hypothesis between phytoplankton density and TP concentratioa during the experiment, but the bottom-up effect occurred between them at the end of the experiment. It was considered that the changes in the nutrient levels (especially for phosphorus) of microcosms resulted primariy from the alterations in their community structure and metabolism intensity caused by silver carp and bighead carp, and it also reflected the effects of fish on nutrient regenerations in the microcosms. |
| Key words: Microcosm silver carp bighead carp nutrient dynamics orthophosphate ammonia phosphorus distribution |
