Quantifying the light sensitivity of Calanus spp. during the polar night: potential for orchestrated migrations conducted by ambient light from the sun, moon, or aurora borealis?
Quantifying the light sensitivity of Calanus spp. during the polar night: potential for orchestrated migrations conducted by ambient light from the sun, moon, or aurora borealis?
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DOI：
10.1007/s00300-013-1415-4
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发表时间：
2015-01-01
期刊：
影响因子：
1.7
通讯作者：
Johnsen, Geir
中科院分区：
文献类型：
--
作者：
Batnes, Anna S.;Miljeteig, Cecilie;Johnsen, Geir
最近的研究表明，北极极夜期间的生物活动比以前认为的要高。浮游动物在黑暗期/冬季进行昼夜垂直迁移，与哲水蚤桡足类哲水蚤属。被假定为有助于观察到的昼夜垂直迁移的主要类群之一。我们调查的敏感性，实地收集哲水蚤种。通过将个体保持在水族箱中并将它们暴露于逐渐增加的白色、蓝色、绿色和红色波段的辐照度，用近红外敏感摄像机记录它们的趋光反应。用两个最古老的桡足类阶段以及成年雄性和雌性进行实验。桡足类是负趋光性的，对于白色、绿色和蓝色波段，引起显著趋光性反应的最低辐照度为10（-8）-10（-6）μ mol光子m（-2）s（-1）的数量级，而对于红色波段，相对辐照度高达三个数量级。不同发育阶段的桡足类对光照的敏感性不同。在极夜最黑暗的部分，显著响应的最低辐照度对应于环境表面辐照度的0.0005 - 0.5%，取决于光源。因此，Calanus spp.可能对70 - 80米深的夜空、120 - 170米深的月光和80 - 120米深的北极光的辐照度有反应。对蓝光和绿色光的高敏感性可以解释哲水蚤在极夜进行昼夜垂直迁移的能力，此时环境辐照度的强度和日变化较低。
Recent studies have shown that the biological activity during the Arctic polar night is higher than previously thought. Zooplankton perform diel vertical migration during the dark period/winter, with the calanoid copepods Calanus spp. being one of the main taxa assumed to contribute to the observed diel vertical migration. We investigated the sensitivity of field-collected Calanus spp. to irradiance by keeping individuals in an aquarium and exposing them to gradually increasing irradiance in white, blue, green, and red wavebands, recording their phototactic response with a near-infrared-sensitive video camera. Experiments were performed with the two oldest copepodite stages as well as adult males and females. The copepods were negatively phototactic, and the lowest irradiance eliciting a significant phototactic response was of the order of 10(-8)-10(-6) mu mol photons m(-2) s(-1) for white, green, and blue wavebands, whereas the comparative irradiance for red wavebands was up to three orders of magnitudes higher. The different copepod developmental stages displayed different sensitivities to irradiance. During the darkest part of the polar night, the lowest irradiance for significant response corresponded to 0.0005-0.5 % of the ambient surface irradiance, depending on light source. Accordingly, Calanus spp. may respond to irradiance from the night sky down to 70-80 m, moonlight to 120-170 m, and aurora borealis down to 80-120 m depth. The high sensitivity to blue and green light may explain the Calanus' ability to perform diel vertical migration during the polar night when intensity and diurnal variation of ambient irradiance is low.