水文变化对巴松措食物网结构及碳来源的影响

Effect of hydrologic changes on the structure and carbon source of the food web in Lake Basomtso

实验应用稳定同位素技术及贝叶斯混合模型对西藏湖泊巴松措水文时期的食物网结构及碳的来源进行了探究。结果显示:巴松措食物网δ13C在-28.66‰^-12.19‰变化,δ15N值的变化为0.01‰~10.50‰;鱼类营养级的范围为2.99~3.71,平均营养级为3.36。在四种基础食物源中,附着藻类对巴松措食物网贡献度最高,占33.09%。外源性碳是巴松措食物网最主要的碳来源,占59.63%。杂食性鱼类在枯水季对内源性碳需求度更高,而丰水季对外源性碳需求度更高。结果表明由枯水季到丰水季的水文变化没有改变消费者利用附着藻类的能力,但对消费者利用外源性碳有积极作用。

This experiment investigated the effect of hydrologic changes on the structure and carbon source of the food web in Basomtso Lake using the stable isotope technique and Bayesian mixture model.The experimental results showed thatδ13 C of the food web varied from-28.66‰to 12.19‰,and the range ofδ15 N varied from 0.01‰to 10.50‰.The trophic level of fish ranged from 2.99 to 3.71,with the average trophic level of 3.36.The periphytic algae contributed at the highest level to the food web in the Lake,accounting for 33.09%.The carbon source of the food web in the lake primarily derived from allochthonous carbon which accounted for 59.63%.Omnivorous fish had a high demand for endogenous carbon during the dry season,while they had a high demand for allochthonous carbon during the wet season.Hydrologic change from the dry season to the wet season did not alter the ability of consumers in utilising periphytic algae.Moreover,this hydrologic change exerted a positive effect on the utilisation of exogenous carbon by consumers.