现场模拟光照条件对南极大磷虾冬季耗氧率的影响研究

为探究海上现场光照条件对冬季南极大磷虾(Euphausia superba)代谢的影响,基于海上暂养实验,采用黑暗组和光照组两种不同的实验条件,对9尾南极大磷虾个体进行了连续11 d的耗氧率研究。结果表明,光照条件下南极大磷虾的单位体质量耗氧率平均为(0.2704±0.0740)μL·(mg·h)^-1,黑暗条件下的单位体质量耗氧率平均为(0.2673±0.0840)μL·(mg·h)^-1。在光照与黑暗条件下南极大磷虾呼吸率无显著差异。通过对比发现,冬季南极大磷虾的耗氧率明显低于夏季的耗氧率0.63~0.88μL·(mg·h)^-1],且改变一个自然日的光照条件对南极大磷虾耗氧率无显著影响,但会在一定程度上影响南极大磷虾呼吸率的稳定性。研究验证了冬季南极大磷虾处于一种低代谢模式状况,并证明了该模式的稳定性。相关结果可为揭示南极大磷虾越冬机制提供基础数据。

Effect of in-situ simulated light levels on respiration rate of Euphausia superba in winter

As the key species in the Southern Ocean,how Antarctic krill(Euphausia superba,hereafter krill)survives through the extremely severe winter time is always one of the key issues for krill ecology.Krill can utilize different strategies to tackle the long winter time,and in which the most effective pattern is to decrease the metabolism and subsequently to reduce the energy consumption.The studies available indicate that the lighting condition could be the key of low energy consumption pattern;however,the in situ data are extremely limited.The oxygen consumption rate usually reflects the metabolic rate of organisms.Therefore,in order to explore the effect of in situ lighting conditions on the metabolism of krill,this study measured the oxygen consumption of krill during the successive 11 days under dark and lighting conditions based on the in situ aquarium experiment.In the experiment,the krill was placed in a closed bottle,and the respiration rate of the krill over a period of time was obtained by measuring the difference in the oxygen concentration of the seawater in the bottle before and after the experiment.A robust linear simulation method was used to eliminate the influence of outliers on the trend of daily variation in respiration rate of krill.Results showed that the average weight specific respiration rate of krill under light conditions was(0.2704±0.0740)μL·(mg·h)^-1,and the average weight specific respiration rate under dark conditions was(0.2673±0.0840)μL·mg(·h)-1.In this study,in a period close to a natural day,the experimental group of krill was repeatedly tested by changing the conditions of darkness and 100 lx light intensity.The experimental results showed that the oxygen consumption level of krill did not show significant fluctuation.The comparative analysis demonstrated that the oxygen consumption of krill in the winter was significantly lower than that in the summer.The change of lighting condition within a natural day did not impact significantly on oxygen consumption of krill,but the stability of respiration rate of krill was impacted.The study supported the observation that krill was on low metabolism pattern during the winter time,and the stability of such pattern was also proved.The conclusion in the study will provide important basic data for revealing the overwintering mechanism of krill.