三疣梭子蟹不同养殖模式池塘叶绿素a的变化特征及粒级结构

On the variation and size-fractionated chlorophyll a in ponds with Portunus trituberculatuscultured in different models

2010年6～11月在三疣梭子蟹(Portunus trituberculatus)3种不同养殖模式的池塘中观测了叶绿素a浓度的变化及其粒级结构。结果表明:池塘中叶绿素a浓度变化范围为(5.29±0.13)～(48.00±15.03)mg.m-3,最低值出现在养殖初期6月份,最高值出现在夏季8月份。养殖期间,池塘叶绿素a浓度显著高于港湾和近海。比较3种不同养殖模式的叶绿素a浓度,以"高位池"最高,"底充氧"其次,"增氧机"最低,但叶绿素a浓度的变化规律基本一致,呈现出养殖初期低,然后迅速上升,至8月份达最高值,再缓慢下降。分析认为,在海水养殖生态系统中,叶绿素a浓度主要受环境因子尤其是营养盐浓度分布的影响。三疣梭子蟹养殖池塘中叶绿素a浓度粒级结构表明,Nano-粒级为主要贡献者,平均贡献率达66.9%;Pico-粒级次之,平均贡献率为22.8%;Net-粒级贡献率最小,仅为10.3%。在三疣梭子蟹养殖池塘中,Nano-粒级浮游植物是初级生产力的主要来源,而Pico-粒级光合微生物对初级生产力的作用不容小视。

The concentration and size-fractionated chlorophyll a in ponds with Portunus trituberculatus cultured in three models were observed from June to November,2010.The results showed that the chlorophyll a concentration range was（5.29±0.13）-（48.00±15.03）mg·m-3;the minimum appeared in June,while the maximum in August.During the culture period,the chlorophyll a concentration in ponds was significantly higher than that of the estuaries and offshore.Among three culture models,the chlorophyll a concentration in ＂high-intensive pond＂ was the highest,the next was the ＂submerged aeration＂ culture model,and the minimum appeared in the ＂aeration＂ culture model.However,the variation of the chlorophyll a concentration was basically the same： in the early period the concentration was low,then rose quickly to the peak in August,and finally slowly declined.After analyzing the marine aquaculture ecosystem,the author found that chlorophyll a concentration was affected mainly by environmental factors,especially nutrient distribution.The size-fractionated chlorophyll a in Portunus trituberculatus ponds showed that the Nanoplankton was the main contributor,the next were Picoplankton and Netplankton,and the average contribution rate was 66.9%,22.8% and 10.3%,respectively.In the Portunus trituberculatus culture pond,the Nanoplankton phytoplankton was the main source of the primary productivity,and the Picoplankton photosynthetic microorganism also played an important role in the primary productivity.