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The expanding culture of fish in coastal areas has raised issues concerning resource use conflicts and water quality problems. A major concern is pollution resulting from nitrogen and phosphorus lost to the environment from feed wastage and fish excretion. The purpose of the study was to assess the environmental conditions in a river system affected by fishponds. Nutrient fluxes and productivity measurements were obtained from Sta. Rita River, a river estuary used as a discharge and an irrigation area of approximately 316 ha of fishponds. During the dry season, when freshwater influence is absent, salinity values inside the river were higher than outside (in the bay). Nutrient trends during ebb and flood periods were similar except for some lag in the profiles that indicate tidal oscillation. The absence of river flow during the dry period resulted in a negligible flux of nutrients along the river. During the wet season, the increase in nitrate concentrations indicates river inputs while the decrease in phosphate values imply less of freshwater influence but more from ponds and domestic wastes. Similarity in productivity estimates signifies good agreement between direct and indirect methods. The absence of flushing during the dry season translates to trapping of nutrients discharged from the ponds in the drainage canals.  相似文献   
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氮、磷等营养物质对低洼盐碱地鱼塘水质的影响   总被引:4,自引:0,他引:4  
高光  胡文英  李宽意 《湖泊科学》2001,13(4):345-350
通过在实验围隔中添加不同浓度的氮、磷等营养物质,对黄淮海平原低洼盐碱地鱼塘中的水质变化情况进行了初步研究,结果表明:1)围隔水体中异养细菌数量的变动,与水体中氮、磷等营养物质的浓度及比例密切相关,尤其是水体中磷的浓度对异养细菌数量的影响更为显著。2)围隔水体中的氮、磷等营养浓度及比率,明显地影响着其中藻类的数量和生物量。在实验条件下,水体中磷对藻类生长的影响要大于氮对藻类生长的影响,水体中N:P比为10:1左右是比较适宜藻类生长的比例。3)围隔水体中氮、磷等营养盐的去除能力与其中藻类的生物量及水体中N:P的比率密切相关,当围隔水体中的N:P比为10:1左右时,围隔水体中的藻类生长最好,生物量增加最快,相应地其对TN、TP的去除率也是最高的。  相似文献   
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