九龙江河口区养虾塘水体营养盐与叶绿素a含量的变化特征及影响因素

Variation of Nutrients and Chlorophyll a Contents in the Shrimp Ponds of Jiulong River Estuary and Their Influencing Factors

于2015年6月18日(养殖初期)、8月20日(养殖中期)和10月10日(养殖后期),在九龙江河口区3个陆基对虾(Penaeus vannamei)养虾塘,采集不同深度的水样,在实验室中,对水样进行测试分析,探讨九龙江河口区养虾塘水体中的可溶性无机氮、磷酸盐和叶绿素a(chlorophyll a)含量变化特征及其主要影响因素。研究结果表明,养虾塘水体中的可溶性无机氮、磷酸盐和叶绿素a的质量浓度分别为0.67~1.25 mg/L、0.019~0.148 mg/L和24.71~110.23μg/L,三者都是在养殖中期最大,在养殖初期最小;在不同养殖阶段,养虾塘水体中的营养盐含量随水深的变化略有差异,在每个养殖阶段,从水体表层到底层,水体叶绿素a含量都在逐渐减小。养虾塘水体中的营养盐含量受不同养殖阶段水质参数(水温、p H、溶解氧含量和盐度)、饵料投喂强度和虾生命代谢活动等因素影响,水体叶绿素a含量主要受到水温、盐度、营养盐含量和虾生物量的影响。

Temporal variation of the contents of dissolved inorganic nitrogen, phosphate and chlorophyll a at different depth and the possible nutrient limitation to the phytoplankton growth were investigated in the Jiulong River estuary, southeastern China. Water samples were collected using a hydrophore from three shrimp（Penaeus vannamei） ponds in June 18, August 20, and October 10, 2015. Meanwhile, water quality indicators（water temperature, p H, dissolved oxygen and salinity） also were measured in situ using portable instruments. Water nutrients analyses were preformed using an automatic continuous flow analyzer. The chlorophyll a samples were extracted with 90% ethanol and measured using an ultraviolet and visible spectrophotometer. During the study period, the contents of dissolved inorganic nitrogen, phosphate and chlorophyll a from shrimp ponds ranged from 0.67 to 1.25 mg/L, 0.019 to 0.148 mg/L, and 24.71 to 110.23 μg/L,respectively, with mean values of（0.94 ± 0.04） mg/L,（0.068 ± 0.003） mg/L and（69.45 ± 4.88） μg/L. Water nutrients and chlorophyll a varied significantly during aquaculture stages and followed the order： August（middle stage）, October（late stage） and June（initial stage）. However, no significant difference of water nutrients and chlorophyll a concentrations among the sampling depth was recorded. Temporal variations of dissolved nutrients contents were influenced by the interactions of water quality indicators, bait feeding, and the foraging and metabolic activity of shrimp, while those of chlorophyll a contents were primarily affected by water nutrient contents, water quality indicators（temperature, salinity, and p H） and shrimp biomass.