北黄海褡裢岛海藻场邻近海域大型底栖动物群落营养结构的季节变化

Seasonal variations of macrozoobenthic community trophic structure in the waters adjacent to the seaweed beds of Dalian Island in the North Yellow Sea

为探明大型海藻盛衰期间海藻碎屑输出变化对邻近生境大型底栖动物群落营养结构的影响,于2020年5月(海藻生长期)和8月(海藻衰亡期)在北黄海褡裢岛海藻场邻近海域采集大型底栖动物,运用碳氮稳定同位素技术分析了大型底栖动物群落营养结构的季节性变化。结果表明:2020年5月和8月大型底栖动物的δ^(13)C和δ^(15)N值分别为-23.14‰~-14.24‰、6.21‰~12.90‰和-22.36‰~-14.13‰、5.33‰~12.00‰。置换多元方差分析(PERMANOVA)结果表明,大型底栖动物月份间δ^(13)C值差异显著,而δ^(15)N值差异不显著。基于欧氏距离,两个月份的大型底栖动物群落均可划分为5组营养功能群。5月大型底栖动物营养级位于2.00(小亮樱蛤)~3.97(锥唇吻沙蚕),8月位于2.00(小亮樱蛤)~3.96(锥唇吻沙蚕)。反映群落营养结构指标的δ^(13)C范围、δ^(15)N范围、平均质心距离、总面积以及矫正标准椭圆面积均以8月取值更高,表明褡裢岛近岸海藻场邻近海域大型底栖动物群落的摄食营养多样性水平和营养生态位宽幅在海藻衰亡季节更高。

To investigate the effects of algal detritus export on the trophie structure of macrozoobenthic community in the adjacent benthic habitat during the bloom and decline of macroalgae,we collected macrozoobenthos from the adjacent sea area of Dalian Island in the North Yellow Sea in May(the algal bloom period)and August(the algal decay period)of 2020.We quantifyied the seasonal changes in the trophic structure of macrozoobenthic community by using carbon and nitrogen stable isotope techniques.Results showed thatδ^(13)C andδ^(15)N values of macrozoo-benthos in May ranged from-23.14‰to-14.24‰,6.21%o to 12.90‰,respectively,and-22.36‰to-14.13‰,5.33‰to 12.00%,respectively in August.Results of PERMANOVA analysis showed thatδ^(13)C values of macrozoo-benthos differed significantly between the two months,whileδ^(15)N values were not significantly different.Based on the Euclidean distance,the macrozoobenthic communities in both months could be classified into five trophic func-tional groups.The trophic levels of macrozoobenthos ranged from 2.00(Niidotellina minuta)to 3.97(Glycera.onomichiensis)in May and from 2.00(N.minuta)to 3.96(G.onomichiensis)in August.Theδ^(13)C range,δ^(15)N range,mean centroid distance,total area and corrected standard ellipse areas which represented community trophie structure indices in August were higher than those in May.Our results indicated that the trophie diversity level and trophic niche width of the macrozoobenthic community in the adjacent sea area of the seaweed bed were higher in the algal decline season.