枸杞岛海藻场角蝾螺夏季摄食选择性及其生态学意义

The feeding behaviour and ecological function during summer of one herbivore on seaweed bed in Gouqi Island: the gastropod,Turbo cornutus Solander

于2013年夏季对枸杞岛海藻场螺类优势种角蝾螺进行了稳定同位素、摄食选择性、消化代谢物粒径等系列实验。稳定同位素结果显示,角蝾螺是牧食性生物,在藻场中的营养级为2.12,属初级消费者,底栖海藻是角蝾螺的主要食源,贡献率为94.5%;摄食选择性实验结果显示,角蝾螺具有较宽的摄食选择,能够摄食海带、铜藻、粗枝软骨藻等11种大型藻类,其中铜藻及蜈蚣藻是枸杞岛潮下带的重要优势种;消化代谢物实验结果显示,角蝾螺的啃食作用能为藻场碎屑提供增量,角蝾螺对海藻场碎屑的增量为（0.016-0.094）g/d,经过啃食及消化作用产生的碎屑主要粒级为1Φ（〉250μm）。稳定同位素分析—摄食选择偏好实验—螺类消化代谢物粒径分析的系列研究表明,角蝾螺在枸杞岛海藻场的群落食物网中,可以起到连接牧食食物链和碎屑食物链的重要作用。

Stable isotope and laboratory （feeding selectivity ＆ detritus size-fraction）experiments were used to investigate feeding behavior and ecological function of the gastropod, Turbo cornutus Solander （T. cornutus） ,living on the seaweed bed during the summer,2013. Stable isotope analysis demonstrated that T. cornutus is herbivore and primary consumers （trophic level is 2.12）in seaweed bed, and prefers seaweed （ 〉 94.5 % ） to other potential food resources （ phytoplankton, POM and SOM）. Laboratory experiments revealed that T. cornutus could feed （ 〉 0. 1 g individual - 1 day - 1, wet weight） 11 different seaweeds （ including the dominant seaweed species of Gouqi Island： Sargassum horneri and Grateloupia livida）. Detritus size-fraction experiments provided evidence that T. cornutus can digest seaweed, then excrete detritus （0. 016 -0. 094）g/d into small size（dominant detritus size is 1Φ（〉250μm）,these change of matter size-fractionate caused by T. cornutus grazing behavior could make contribution to detritus in seaweed bed. Stable isotope experiment, combined with laboratory （ feeding selectivity ＆ detritus size-fraction） experiments suggest T. cornutus plays an important role in connecting grazing food chain and detritus food chain in food web of seaweed bed, Gouqi Island.