Trophic importance of the hyperiid amphipod, Themisto gaudichaudi, in the Prince Edward Archipelago (Southern Ocean) ecosystem
Trophic importance of the hyperiid amphipod, Themisto gaudichaudi, in the Prince Edward Archipelago (Southern Ocean) ecosystem
复制标题
超级片脚类动物 Themisto gaudichaudi 在爱德华王子群岛（南大洋）生态系统中的营养重要性
DOI：
10.1007/s003000050464
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发表时间：
2000
期刊：
影响因子：
1.7
通讯作者：
A. Treasure
中科院分区：
文献类型：
--
作者：
P. Froneman;E. Pakhomov;A. Treasure
摘要1998年夏末（4/5月），在爱德华王子群岛周围沃茨的30个站位调查了端足类Themisto gaudichaudi的摄食动态和捕食对浮游动物群落的影响。T. gaudichaudi使用两种方法，即肠道充盈指数和体外孵育来估计。在整个调查中型浮游动物，包括桡足类，翼足类和毛颚类，数量和生物量占主导地位的邦戈样品。浮游动物丰度和生物量分别为8至271 ind. m−3和1.01至7.47 mg dwt m−3。密度T.研究期间的gaudichaudi值很低，从未超过0.4 ind. m-3。肠内容物分析（n=61）表明T. gaudichaudi是一种非选择性的机会主义食肉动物，通常以最丰富的桡足类和毛颚类物种为食。摄食活动的高峰出现在日出和日落时，对应于它们的昼夜垂直迁移模式。从体外孵育和肠道充盈指数估计的每日口粮分别相当于身体干重的1.2-8.7%和11.5 - 19.8%。T.在300 m以上的水柱中，gaudichaudi平均值较低，占中型浮游动物生物量的0.4%以下，占中型浮游动物次级生产力的3%以下。事实上，捕食的影响很可能是较低的贡献，较小的桡足类（如Oithona spp.）由于采用的取样装置，浮游动物总数被低估。在这项研究中记录的低捕食影响可能与T。gaudichaudi。T.在爱德华王子群岛周围的沃茨中，gaudichaudi作为次级生产消费者，表现出高度的时空变异性。
Abstract The feeding dynamics and predation impact of the hyperiid amphipod, Themisto gaudichaudi, on the zooplankton community in the waters surrounding the Prince Edward Archipelago were investigated at 30 stations in late austral summer (April/May) 1998. Ingestion rates of T. gaudichaudi were estimated using two approaches, the gut fullness index and in vitro incubations. Throughout the investigation mesozooplankton, comprising copepods, pteropods and chaetognaths, numerically and by biomass dominated Bongo samples. Zooplankton abundances and biomass ranged from 8 to 271 ind. m−3 and between 1.01 and 7.47 mg dwt m−3, respectively. Densities of T. gaudichaudi during the study were low, never exceeding 0.4 ind. m−3. Gut content analysis (n=61) indicates that T. gaudichaudi is a non-selective, opportunistic carnivore generally feeding on the most abundant copepod and chaetognath species. Peaks in feeding activity were recorded at sunrise and sunset, corresponding to their diel vertical migration patterns. Daily rations estimated from in vitro incubations and gut fullness index were equivalent to 1.2–8.7% and between 11.5 and 19.8% of body dry weight, respectively. The predation impact of T. gaudichaudi averaged over the upper 300 m of the water column was low, accounting for <0.4% of the mesozooplankton biomass or <3% of the mesozooplankton secondary production. Indeed, the predation impact is likely to be lower as the contribution of the smaller copepods (e.g. Oithona spp.) to total zooplankton was underestimated due to the sampling gear employed. The low predation impact recorded during this study can be related to low abundances of T. gaudichaudi. It is likely that the importance of T. gaudichaudi as a secondary production consumer in the waters surrounding the Prince Edward Archipelago demonstrates a high degree of spatio-temporal variability.