两种碳源对草鱼养殖水质、藻类和微生物群落的影响

摘要

The present research investigated the effect of two different carbon sources on water quality and microbial com -munity in grass carp (Ctenoparyngodon idellus) culture systems.The experiment was carried out in 6 m2 canvas cages stocked with 150 grass carp ( individual weight 25.69 g ±0.73 g) .Starch ( GS) and starch with sodium acetate in the pro-portions of 19∶1 ( GSA) were used as carbon source and applied to the water column once a week .During a 60 d culture period, the total nitrogen (TN), total phosphorus (TP), chlorophyll a (chl a) and the biovolume of phytoplankton in water increased gradually , while secchi disk visibility and C/N ratio declined, and total ammonia nitrogen ( TAN) kept below 0.25 mg/L.The different carbon sources had no significant effect on water quality and phytoplankton community pa -rameters.The average well color development ( AWCD) and Shannon-Weaver index ( H) obtained by the BIOLOG Eco plate assay was higher in GS treatment when compared to GSA treatment , and the differentials increased significantly dur-ing the culture period .This study showed that sodium acetate could reduce activity and diversity of microbial community , and enrich the phytoplankton species number and diversity .%为研究淀粉及其与乙酸钠的复合物（淀粉乙酸钠质量比为19∶1）两种碳源对草鱼养殖水体水质、藻类和微生物群落调控作用的差异，在为期60 d的试验中，每周向养殖水体添加一次碳源，添加量为当日水体氨氮含量的20倍，监测分析水体理化指标、藻类和微生物群落参数。结果显示：（1）试验期内，淀粉组（GS）和淀粉乙酸钠组（ GSA）养殖水体氨氮保持在0．25 mg／L左右，总氮、总磷和叶绿素a均逐步升高，而透明度和碳氮比逐步下降，同次样品两试验组间水体理化指标差异不显著。（2）试验期内， GS组和GSA组藻类数量逐步上升，中后期显著高于前期，同次样品两试验组间藻类数量差异不显著，但GSA组藻类种类数和多样性稍高于GS组。（3） GS组微生物活性、碳源利用能力同比略高于GSA组，且微生物群落多样性在试验末期差异显著。结果表明，淀粉碳源中复合少量乙酸钠可改变藻类和微生物结构功能，可作为池塘养殖水体藻类和微生物群落结构功能定向调控碳源。