黄河三角洲平原型水库大型底栖动物对磷的积累效应

Bioaccumulation of phosphorus by benthic macroinvertebrate in reservoirs at the Yellow River Delta

2003年春、夏、秋季对黄河三角洲7座平原型水库进行了4次调查,发现:1)由摇蚊科幼虫和水蚯蚓构成的大型底栖动物,体内磷含量随底泥沉积磷的增加而增加(P<0．000),底柄动物对沉积磷的积累系数亦随沉积磷含量的增加而增加(p<0．000);2)4、5月份摇蚊幼虫在底栖动物体所占不同比例(20％-100％),没有显示与底柄动物体内磷含量任何关系;3)底栖动物含磷量与水层总磷无显著相关关系;4)底柄动物生物量与沉积总磷仅4月份有相关(p<0．10),其中摇蚊幼虫生物量与沉积磷量相关显著(P<0．05),总体上,水库底柄动物最高生物量随沉积磷增加而增加;5)底栖动物生物量与水层总磷无相关关系,但去掉底层鱼产量高的水库后,8月份二者有显著相关关系(p<0．03),且总体底栖动物最高生物量也随水层总磷增加而增加．认为:1)由摇蚊科幼虫和水蚯蚓构成的大型底柄动物对磷的积累以及摇蚊幼虫的生物量均与水体磷负荷有密切关系;2)摇蚊幼虫和水蚯蚓含磷量(干重)差异不明显;3)以摇蚊幼虫为主的底栖动物对磷的积累主要来自沉积磷的影响,受季节的影响相对较弱;4)底栖动物生物量主要受水层总磷的控制,也受鱼类摄食以及摇蚊幼虫个体羽化时间不一致的影响．

Benthic invertebrate is a keystone in lake food web to connect nutrients in sediment to animals in and above water, such as fish and waterfowl. Phosphorus is believed to be an important factor leading to eutrophication. Some studies illustrated that the benthos biomass increased with concentration of total phosphorous in water column （TP）. The researches on the relationships of phosphorus concentrations in benthic fauna （PIB）, lake sediment （PIS） and water column were carried out for 4 times during 2003 in 7 plain shallow reservoirs at the Yellow River Delta. The results displayed ： （ 1 ） that Chironomidea larvae is the main fauna in the benthos, contributing average 80% to total benthos biomass, and the other species of Tubificidea to 20%, （2） that PIB had a great signifcant positive correlation with PIS, but no significant correlation with TP, （3） that the proportion of the larvae has no significant correlation with PIB, （4） that the larvae biomass （ CB ） had a significant correlation with PIS only in April during the research, meanwhile, the maximums of CBes increase with the PIS, and （5） that maximums of CBes also increase with TP, while there is a significant correlation between CB and TP if the data of a special reservoir is deleted. The conclusion is ： （ 1 ） that the phosphorus bioaccumulation by benthic fauna mainly made up of chironomid and tubificid controlled by PIS, while the influence of the fauna constructions and that of the different seasons can be neglected, and （2） that CB is not only controlled by TP, but also influenced by the predation of fish and emergence nonsynchronization of the larvae.