Seabed foraging by Antarctic krill: Implications for stock assessment, bentho-pelagic coupling, and the vertical transfer of iron
Seabed foraging by Antarctic krill: Implications for stock assessment, bentho-pelagic coupling, and the vertical transfer of iron
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DOI：
10.4319/lo.2011.56.4.1411
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发表时间：
2011-07-01
影响因子：
4.5
通讯作者：
Achterberg, Eric P.
中科院分区：
文献类型：
--
作者：
Schmidt, Katrin;Atkinson, Angus;Achterberg, Eric P.
30多项研究的汇编表明，成年南极磷虾（Euphausia superba）可能全年频繁出现在底栖栖息地，无论是在大陆架还是海洋沃茨水域以及整个极地范围内。来自斯科舍海的网和声学数据表明，在夏季，2-20%的种群居住在200至2000米的深度之间，并且可以在海床上方形成大型聚集体。磷虾的垂直分布的地方差异表明，减少喂养成功的表面沃茨，无论是由于捕食者遇到或食物短缺，可能会启动这样的深迁移，并在底栖动物喂养的结果。胃内容物的脂肪酸和显微镜分析证实了南极磷虾的两种不同觅食生境：上层海洋，新鲜浮游植物是主要食物来源，以及更深的水或海底，碎屑和桡足类被消耗。在上层沃茨捕获的磷虾保留了底栖动物摄食的信号，表明表层和海底之间频繁和动态的交换。磷虾从海底进食返回时，每个胃中含有高达260纳摩尔的铁。大约5%的铁是不稳定的，即，可能对浮游植物有用。由于其巨大的生物量，频繁的底栖摄食，和酸性消化颗粒铁，磷虾可能会促进输入新的铁到南大洋表面沃茨。深海洄游和在海底觅食是磷虾生态学的重要组成部分，这种行为所涉及的垂直通量对于底栖和中上层食物网及其元素库的耦合非常重要。
A compilation of more than 30 studies shows that adult Antarctic krill (Euphausia superba) may frequent benthic habitats year-round, in shelf as well as oceanic waters and throughout their circumpolar range. Net and acoustic data from the Scotia Sea show that in summer 2-20% of the population reside at depths between 200 and 2000 m, and that large aggregations can form above the seabed. Local differences in the vertical distribution of krill indicate that reduced feeding success in surface waters, either due to predator encounter or food shortage, might initiate such deep migrations and results in benthic feeding. Fatty acid and microscopic analyses of stomach content confirm two different foraging habitats for Antarctic krill: the upper ocean, where fresh phytoplankton is the main food source, and deeper water or the seabed, where detritus and copepods are consumed. Krill caught in upper waters retain signals of benthic feeding, suggesting frequent and dynamic exchange between surface and seabed. Krill contained up to 260 nmol iron per stomach when returning from seabed feeding. About 5% of this iron is labile, i.e., potentially available to phytoplankton. Due to their large biomass, frequent benthic feeding, and acidic digestion of particulate iron, krill might facilitate an input of new iron to Southern Ocean surface waters. Deep migrations and foraging at the seabed are significant parts of krill ecology, and the vertical fluxes involved in this behavior are important for the coupling of benthic and pelagic food webs and their elemental repositories.