Frank T M
Division of Marine Science, Harbor Branch Oceanographic Institution, Fort Pierce, FL 34946, USA.
Philos Trans R Soc Lond B Biol Sci. 2000 Sep 29;355(1401):1195-8. doi: 10.1098/rstb.2000.0666.
Mesopelagic crustaceans occupy a dim-light environment that is similar to that of nocturnal insects. In a light-limited environment, the requirement for greater sensitivity may result in slower photoreceptor transduction and increased summation time. This should be reflected by a lower temporal resolution, as indicated by a lower critical flicker fusion frequency (CFF). Therefore, one would predict that the CFFs of mesopelagic organisms would be relatively low compared with those of their shallow-water relatives, just as nocturnal insects tend to have lower CFFs than diurnal insects. Using an electrophysiological apparatus that was adapted for shipboard use, the dark-adapted CFFs of a variety of species of mesopelagic crustaceans were determined using the electroretinogram. The parameter examined was the maximum CFF--the point at which further increases in irradiance no longer result in a faster flicker fusion frequency. The results summarized here indicate that there is a trend towards lower CFFs with increasing habitat depth, with some interesting exceptions.
中层海洋甲壳类动物所处的弱光环境与夜行性昆虫的环境相似。在光照有限的环境中，对更高灵敏度的需求可能导致光感受器转导速度减慢以及总和时间增加。这应该会以较低的时间分辨率体现出来，如较低的临界闪烁融合频率（CFF）所示。因此，可以预测，与浅海同类动物相比，中层海洋生物的CFF会相对较低，就像夜行性昆虫的CFF往往低于昼行性昆虫一样。使用一种适用于船上使用的电生理仪器，通过视网膜电图测定了多种中层海洋甲壳类动物物种的暗适应CFF。所检测的参数是最大CFF——即辐照度进一步增加不再导致闪烁融合频率加快的那个点。此处总结的结果表明，随着栖息地深度增加，CFF有降低的趋势，但也有一些有趣的例外情况。
