有机磷培养下水体浮游植物竞争与群落结构演替

磷是浮游植物生长的必要元素,也是调控水体富营养化的重要因子之一。在无机磷缺乏的水域,能够有效利用有机磷的藻类有可能成为浮游植物群落的优势种。为了研究有机磷对浮游植物群落结构演替的影响,分别从3个水库采集表层水样,西陂水库(硅藻70.3%,甲藻19.1%,绿藻9.3%)、山美水库(硅藻31.3%,甲藻59.2%,绿藻3.5%)、三十六脚湖(硅藻43.1%,甲藻50.5%,绿藻5.0%),选用有机磷单磷酸腺苷(Adenosine monophosphate,AMP)作为磷源进行实验室模拟实验,并与无机磷(NaH_2PO_4·2H_2O)作为磷源实验组做同步对比,探讨有机磷源条件下浮游植物竞争及群落结构演替规律。结果显示:AMP培养20 d后,西陂水库、山美水库和三十六脚湖的浮游植物生物量分别增加了6.5倍,2.1倍和1.9倍,浮游植物群落结构都演替为以甲藻门和绿藻门为优势藻,所占比例分别为81.8%和16.7%、55.2%和33.5%、73.2%和24.3%,其中西陂水库甲藻门拟多甲藻对有机磷AMP的利用能力强,其所占比例达到81.8%。表明有机磷AMP能有效地促进甲藻门拟多甲藻属的增殖,进而改变水体浮游植物群落结构。

Study on the competition and community succession of phytoplankton cultivated with organic phosphorus

Phosphorus is an essential element for phytoplankton growth and also one of the key factors in eutrophication control. In oligotrophic waters with limited phosphorus, algal species which can effectively utilize the organic phosphorus are likely to dominate in the phytoplankton community structure. To study the effects of organic phosphorus on the succession of the phytoplankton community structure, we collected water samples from three reservoirs:Xipi Reservoir (Bacillariophyta, 70.3%;Pyrrophta, 19.1%; Chlorophyta,9.3%), Shanmei Reservoir (Bacillariophyta, 31.3%;Pyrrophta, 59.2%; Chlorophyta, 3.5%) and Thirty-Six-Feet Lake (Bacillariophyta, 43.1%; Pyrrophta, 50.5%;Chlorophyta, 5.0%). For comparing to an inorganic phosphorus source (NaH₂PO₄·2H₂O), we used the adenosine monophosphate (AMP) as an organic phosphorus source for a 20-day cultivation, and discussed the variation in the growth and the succession of the phytoplankton community structure. The results illustrated different increasing rates of the phytoplankton biomass in Xipi Reservoir (6.5-fold), Shanmei Reservoir (2.1-fold) and Thirty-Six-Feet Lake (1.9-fold). Pyrrophta and Chlorophyta became the dominant phytoplankton groups with AMP as the phosphorus source, and their relative abundances were 81.8% and 16.7% in Xipi Reservoir, 55.2% and 33.5% in Shanmei Reservoir, and 73.2% and 24.3% in Thirty-Six-Feet Lake respectively. In Xipi Reservoir, Peridiniopsis Lemmermann had the highest utilization capacity for AMP, and its relative abundance reached 81.8%. Our work suggested the strong promotion of AMP in the proliferation of Peridiniopsis Lemmermann in Pyrrophta, contributing to the variation in the phytoplankton community structure.