扬中夹江浮游植物种群特征及其对环境因子的响应

2017年对扬中夹江4个季度浮游植物进行周年采样调查,研究了浮游植物群落结构特征及变化趋势。共鉴定出6门93种,其中蓝藻门15种,隐藻门3种,甲藻门3种,硅藻门36种,裸藻门5种,绿藻门31种。浮游植物全年优势种共有8种,其中蓝藻门3种,分别为微囊藻(Microcystis sp.)、假鱼腥藻(Pseudoanabaena sp.)和卷曲鱼腥藻(Anabaena circinalis);隐藻门1种为尖尾蓝隐藻(Chroomonas acuta);硅藻门4种,分别为颗粒直链藻(Melosira granulata)、小环藻(Cyclotella sp.)、梅尼小环藻(Cyclotella meneghiniana)和针杆藻(Synedra sp.)。浮游植物年平均生物密度为35.34×10~4个/L,硅藻门和蓝藻门最多(分别占47.45%和42.87%);年平均生物量为0.183 5 mg/L,硅藻门(占比78.42%)是生物量主体。4个季度浮游植物生物量存在极显著差异(P0.01),秋季最高,春季最低;各断面则无显著性差异(P0.05)。RDA冗余分析显示浮游植物生物密度与水温、TDP等有正相关关系,与Chl.a有负相关关系。应用渔产潜力进行估算表明夹江足够供给8头以上的江豚食物。

Phytoplankton community structure in Jiajiang in Yangzhong Estuary and its relation to environmental factors

In the four seasons of 2017, phytoplankton sampling survey was conducted in the Jiajiang in Yangzhong, and the phytoplankton community structure characteristics and trends were studied. A total of 93 species of 6 phyla were identified, including:15 species of Cyanophyta, accounting for 16.13% of the total species of phytoplankton; 3 species of Cryptophyta, accounting for 3.23%; 3 species of Pyrrophyta, accounting for 3.23%; 36 species of Bacillariophyta, accounting for 38.71%; 5 species of Euglenophyta, accounting for 5.38%; 31 species of Chlorophyta, accounting for 33.33%. There are 8 dominant species of phytoplankton in the whole year, including:3 Cyanophyta species, namely microcystis, pseudoanabaena and Anabaena circinalis, 1 species of cryptophylum, namely chromonas acuta. There are 4 species of bacillariophyta, namely Microcystis granulosa, Microcystis meniere and Synedra sp. The annual average biological density of phytoplankton is 35.34×10⁴ cells/L, with Bacillariophyta and Cyanophyta accounting for 47.45% and 42.87% respectively. The annual average biomass was 0.183 5 mg/L, and Bacillariophyta (accounting for 78.42%) had the main biomass. There were significant differences in phytoplankton biomass in 4 quarters (P<0.01), highest in autumn, lowest in spring, and no significant difference in each section (P>0.05). The RDA redundancy analysis shows that the biomass density of phytoplankton is positively correlated with water temperature, TDP and so on, which is negatively correlated with Chl.a. Estimation of fishing potential shows that Jiajiang River is enough to feed more than 8 finless porpoise.