Feeding and energy budgets of larval Antarctic krill Euphausia superba in summer
Feeding and energy budgets of larval Antarctic krill Euphausia superba in summer
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DOI：
10.3354/meps257167
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发表时间：
2003-08
影响因子：
2.5
通讯作者：
B. Meyer;A. Atkinson;B. Blume;U. Bathmann
中科院分区：
文献类型：
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作者：
B. Meyer;A. Atkinson;B. Blume;U. Bathmann
2000 年 2 月至 3 月，在罗瑟拉时间序列监测站（南纬 67°34'，西经 68°07'，阿德莱德岛，南极半岛西部）对磷虾主要幼虫阶段（calyptopis III 期、Furcilia I 期和 II 期）的生理状况和摄食活动进行了调查。在整个研究期间，密集的浮游植物水华（5 至 25 µg chl a l -1 ）占据了混合层。通过在天然海水中孵化动物来测量幼虫的摄食情况。整个实验中食物浓度范围为 102 至 518 µg C l -1，平均每日 C 配给量为 3 期 (CIII) 体 C 的 28%、I 期 (FI) 体 C 的 25% 和 FII 期 15%。浮游植物以硅藻和活动猎物类群为主，大小范围为 8 至 79 µm。在硅藻的这种尺寸范围内，CIII 清除小细胞的效率最高，FI 的清除效率较低。然而，FII 对于特定的细胞大小没有显示出明显的趋势。在运动类群的测量尺寸谱中，所有幼虫阶段都表现出对较大细胞的明显偏好。估计的碳同化效率很高，从 70% 到 92%（平均 84%）。新鲜捕获的幼虫的呼吸速率为0.7至1.1 µl O2 mg DM -1 h -1 。计算得出的呼吸碳损失显示，在所有幼虫阶段，随着食物浓度的增加，呼吸碳损失显着增加，范围为身体碳d -1 的0.9%至2.4%。这些呼吸损失加上高同化效率，使幼虫在这些食物浓度下有足够的生长能力。达到最大每日配给量的食物临界浓度范围为 100 至 200 µg C l -1 （~2 至 4 µg chl a l -1 ）。因此，南极半岛沿线的高产陆架区，如罗瑟拉岛，可能是磷虾幼虫良好的“育苗地”。
The physiological condition and feeding activity of the dominant larval stages of Eu- phausia superba (calyptopis stage III, furcilia stages I and II) were investigated from February to March 2000 at the Rothera Time Series monitoring station (67° 34' S, 68° 07' W, Adelaide Island, West- ern Antarctic Peninsula). A dense phytoplankton bloom (5 to 25 µg chl a l -1 ) occupied the mixed layer throughout the study period. The feeding of larvae was measured by incubating the animals in natural seawater. Food concentrations ranged from 102 to 518 µg C l -1 across experiments, and the mean daily C rations were 28% body C for calyptosis stage III (CIII), 25% for furcilia stage I (FI) and 15% for FII. The phytoplankton, dominated by diatoms and motile prey taxa, ranged from 8 to 79 µm in size. Across this size spectrum of diatoms, CIII cleared small cells most efficiently, as did FI to a lesser degree. FII, however, showed no clear tendency for a specific cell size. Across the measured size spectrum of the motile taxa, all larvae stages showed a clear preference towards the larger cells. Estimated C assimi- lation efficiencies were high, from 70 to 92% (mean 84%). Respiration rates of freshly caught larvae were 0.7 to 1.1 µl O2 mg DM -1 h -1 . The calculated respiratory C loss showed a significant increase with increasing food concentration in all larval stages, ranging from 0.9 to 2.4% body C d -1 . These respira- tory losses, combined with the high assimilation efficiencies, thus give the larvae ample capacity for growth at these food concentrations. Critical concentrations of food to achieve maximum daily rations were in the range of 100 to 200 µg C l -1 (~2 to 4 µg chl a l -1 ). Thus productive shelf sites along the Antarctic Peninsula, such as Rothera, may act as good 'nursery' areas for krill larvae.