湛江球形棕囊藻赤潮除藻试验

Experiments in Removing Red Tide Alga Phaeoecystis globosa from Zhanjiang by Algicides

摘要:

2005年4月,在广东湛江港赤潮区采集球形棕囊藻（Phaeoecystis globosa）,在室内用新洁尔灭和异噻唑啉酮两种除藻剂进行棕囊藻的杀灭试验。结果表明，新洁尔灭对赤潮水体中球形棕囊藻的72 h LC₅₀为0．96mg L^-1；与新洁尔灭相比，异噻唑啉酮的除藻效果更为明显，其对球形棕囊藻的72 h LC₅₀为0.54 mg L^-1。新洁尔灭和异噻唑啉酮复配时具有协同作用，可提高除藻能力，新洁尔灭和异噻唑啉酮浓度比为1.3：0.3（配比为4.3：1）时除藻效果最优，2 d的除藻率达到89％，协同指数为0.78。两种除藻剂对鲻鱼（Mugil cephdus）苗72 h的毒性试验表明，新洁尔灭和异噻唑啉酮浓度分别在2.0和0.3mg L^-1以下除藻是安全的。

关键词:球形棕囊藻：除藻剂;新洁尔火;异噻唑啉酮;协同效应;广东

Abstract:

Algicides, bromogeramine（B）and isothiazolone（I），were used for removing Phaeoecystis globosa in the experiments in containers of 450 ml seawater with 109 cells L^-1 of algae collected in April 2005 from Zhanjiang Seaport, Guangdong Province, where red tide had happened in January 2004. The results showed that LC50 of isothiazolone was 0.54 mg L^-1 for the algae treated for 72 hours, which was more effective than that of bromogeramine （LC₅₀=0.96 mg L^-1）. Alga-removal effects of both algicides used in combination showed synergistic action. The proportion ofbromogeramine to isothiazolone being 4.3 to 1 gave best result. Toxicity tests on little fishes （Mugil cephdus） showed that 2.0 mg L^-1 bromogeramine or 0.3 mg L^-1 isothiazolone were safe for fishes in the removal of algae in 72 hours.

Key words:Phaeoecystis globosa;Algaecide;Bromogeramine;Isothiazolone;Synergistic effect;Guangdong