光裸方格星虫初期海球幼体对温度和盐度的耐受试验

Study on both Temperature and Salinity Tolerances of the earliest pelagospheric larvae of Sipunculus nudus

在实验室条件下开展光裸方格星虫初期海球幼体对温度和盐度的耐受实验。结果表明,在盐度32,试验时间24h内,光裸方格星虫幼体的正常发育生长温度范围为22～38℃,临界上限水温为39℃,临界下限水温为1℃。耐受的盐度范围较广,在试验时间48h内,温度26～27℃条件下,盐度17～47范围内幼体都可存活,其中盐度24～36试验组幼体发育正常,在中上水层游动,具趋光性和聚集性,生长速度较其它试验组快;临界上限盐度为50,临界下限盐度为14。这些表明光裸方格星虫初期海球幼体对低盐度相对敏感,对高盐度有较强的耐受力,而对温度特别是低温的耐受能力也较强。

The temperature and salinity tolerances on the earliest pelagospherie larvae of peanut worn Sipunculus nudus were conducted in this study. The results showed that the earliest pelagospherie larvae could normally develop at the temperature range of 22 -38 ℃, within S =32 ‰, 24 hours, and the critical upper and lower limit temperature were 39 ℃ and 1 ℃, respectively. While there was a more wide salinity range of 17 -47 ‰ that the earliest pelagospheric larvae could keep alive, within T =26 - 27℃, 48 hours, meanwhile under the optimum salinity range of 24 -36 ‰ the earliest pelagospheric larvae could normally develop and swim in middle and upper water with phototaxis and aggregation, also grow faster than other experimental groups. The critical upper and lower limit salinity were 50 ‰ and 14‰, within T =26 -27℃, respectively. The results revealed that the earliest pelagospheric larvae of Sipunculus nudus were more sensitive to the lower salinity, while were able to suffer a higher salinity and a lower temperature.