Wright D A, Purcell J E
Biol Bull. 1997 Apr;192(2):332-339. doi: 10.2307/1542726.
Mesohaline populations of the scyphomedusae Chrysaora quinquecirrha are found in salinities ranging from 5{permill} to 25{permill}. Osmotic and ionic adjustments within this salinity range were investigated using C. quinquecirrha ephyrae budded from polyps in the laboratory and young medusae collected from the mid-salinity region of the Patuxent River, Maryland. When medusae were transferred from 20{permill} salinity to lower salinities (8{permill}, 12{permill}), concentrations of sodium and magnesium in tissue and mesogleal fluid fell rapidly and approached those of dilute seawater within 6 hours. There was some recovery of these levels relative to the 8{permill} medium, and they were significantly higher than the dilute seawater concentration after 1 week. Tissue concentrations of calcium showed no evidence of being regulated, whereas potassium was strongly regulated such that levels did not fall significantly following transfer of medusae to lower salinities. However, after 1 week, the concentration of potassium in mesogleal fluid approached that of the dilute medium. Extracellular space measured by direct blotting and weighing or using 35S was about 40%. As a result, estimates for intracellular potassium were revised to 17 mM1-1. The concentration of potassium in tissue remained stable following transfer to lower salinity, despite a substantial osmotic influx of water. This influx was measured as a >20% gain in body weight over 24 h following transfer of medusae from 16{permill} to 8{permill}. Mesogleal fluid was slightly hypo-osmolar to the medium at 15% and 20{permill} and slightly hyperosmolar to the medium at 5{permill} and 12{permill}. Sulfate concentrations in mesogleal fluid were 66%-70% those of the external medium. Medusae died or were unable to achieve positive buoyancy at 5%{permill}, which is probably very close to a lower salinity limit for C. quinquecirrha in the mesohaline Chesapeake Bay.
在盐度范围为5‰至25‰的水域中发现了钵水母纲的金色水母（Chrysaora quinquecirrha）的中盐度种群。利用在实验室中从水螅体上出芽的金色水母碟状体以及从马里兰州帕塔克森特河的中盐度区域采集的幼体水母，对该盐度范围内的渗透和离子调节进行了研究。当将水母从20‰的盐度转移到较低盐度（8‰、12‰）时，组织和中胶层液中的钠和镁浓度迅速下降，并在6小时内接近稀释海水的浓度。相对于8‰的介质，这些水平有一定程度的恢复，并且在1周后显著高于稀释海水的浓度。组织中的钙浓度没有显示出被调节的迹象，而钾则受到强烈调节，以至于在将水母转移到较低盐度后其水平没有显著下降。然而，1周后，中胶层液中的钾浓度接近稀释介质的浓度。通过直接印迹称重或使用35S测量的细胞外空间约为40%。因此，细胞内钾的估计值被修订为17 mM1-1。尽管有大量的水渗透流入，但在转移到较低盐度后，组织中的钾浓度仍保持稳定。在将水母从16‰转移到8‰后的24小时内，这种流入量被测量为体重增加超过20%。中胶层液在15%和20‰时略低于介质的渗透压，在5‰和12‰时略高于介质的渗透压。中胶层液中的硫酸盐浓度为外部介质的66%-70%。在5‰时，水母死亡或无法实现正浮力，这可能非常接近切萨皮克湾中盐度区域金色水母的低盐度极限。
