青山湖沉积物中枝角类卵鞍密度的垂直变化及其与营养盐的关系

The Vertical Changes of Ephippial Densities of Cladoceran Species in the Sediment of Lake Qingshan and Its Correlation with the Nutrients

研究江西省青山湖沉积物中枝角类卵鞍密度的垂直变化.在青山湖的沉积物中,共鉴定出枝角类卵鞍8种.其中,大型溞属枝角类卵鞍3种(中华拟同形溞、蚤状溞和盔形溞),小型枝角类卵鞍5种(角突网纹溞、一种象鼻溞、粗刺大尾溞、微型裸腹溞和一种网纹溞). 1#采样点的沉积柱中枝角类总卵鞍和含休眠卵卵鞍的密度范围分别为0~14.4 ind./(g·dw)和0~4.6 ind./(g·dw),2#采样点则分别为0~9.2 ind./(g·dw)和0~3.7 ind./(g·dw).蚤状溞的卵鞍密度在大型溞属枝角类中占据优势,而角突网纹溞的卵鞍密度在小型枝角类中占据优势. 8种枝角类卵鞍的密度最大值均出现在表层9~1 cm的沉积层中. Pearson相关性显示,青山湖2#采样点沉积物中的总氮TN和总磷TP含量与中华拟同形溞、蚤状溞、角突网纹溞、象鼻溞和粗刺大尾溞的卵鞍密度之间均存在显著的相关性(P<0.05).结果表明,沉积柱中营养盐含量和枝角类卵鞍的垂直变化反映青山湖富营养化和枝角类群落结构的历史演变过程.

In this paper,the vertical changes of ephippial densities of cladoceran species in the sediments of Lake Qingshan,Jiangxi province were studied.In the sediments of Lake Qingshan,8 species of cladoceran ephippia were identified,including 3 large-sized species(Daphnia similoides sinensis,D.pulex,and D.galeata)and 5 small-sized species(Bosmina sp.,Leydigia leydigii,Moina micrura,Ceriodaphnia sp.,and C.cornuta).The densities of total ephippia and ephippia containing resting-eggs of cladocera in the sediments of the 1#sampling site ranged from 0 to 14.4 ind./(g·dw),and from 0 to 4.6 ind./(g·dw),respectively.At 2#sampling site,these densities ranged from 0 to 9.2 ind./(g·dw),and from 0 to 3.7 ind./(g·dw),respectively.The total ephippial densities of D.pulex were dominant in large-sized cladocera,while the total ephippial densities of C.cornuta dominated in small-sized cladocera.All the maximal densities of 8 cladoceran ephippia appeared in the 9-1 cm surface sediment layer.There were significant relationships between total nitrogen(TN)and total phosphorus(TP)contents in the 2#sediment core and the total ephippial densities of D.similoides sinensis,D.pulex,C.cornuta,Bosmina sp.and L.leydigii(P<0.05).The results suggested that the vertical changes of the nutrient contents and cladoceran ephippia in the sediment core could reflect the historical succession of eutrophication and community structure of cladocera in Lake Qingshan.