Herbicides are an integral part of global agricultural activity but can be advected into local drainages that can discharge to coastal marine systems. Herbicide runoff can impact coastal marine organisms, including those associated with coral reefs and coastal mangrove forests. In this study, the symbiotic sedentary jellyfish Cassiopea maremetens were exposed to analytical grade hexazinone to determine their sensitivity and potential for recovery after exposure to a press herbicide event of 14 days followed by a recovery period of matching duration. Bell surface area, photosynthetic yield (i.e. effective quantum yield, EQY), statolith count and zooxanthellae density were analyzed. Most metrics demonstrated significant decreases when exposed to higher concentrations of hexazinone, while EQY was significantly decreased at exposure concentrations from 31 μg/L hexazinone and above. In contrast, zooxanthellae density (cells/mm2) increased in the highest concentrations compared to control animals. At the end of the exposure period the EC50 for bell surface area, EQY, and statolith count were 176 μg/L, 81.96 μg/L, and 304.3 μg/L, respectively. Jellyfish were able to recover to similar start values for all measured metrics at the end of the 14-day recovery period, with EQY showing recovery by Day 7 of the recovery period. This study demonstrated that statolith counts as an estimate of age were not affected by herbicides. We conclude that the depressed metrics from herbicide related impacts of C. maremetens are effective indicators of a relatively recent herbicide perturbation in that the recovery timeframe for these jellyfish is relatively short.

中文翻译：

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检测除草剂径流的影响：使用Cassiopea maremetens作为六嗪酮的生物监测剂。

除草剂是全球农业活动中不可或缺的一部分，但可以引入到可以排入沿海海洋系统的当地排水渠中。除草剂径流会影响沿海海洋生物，包括与珊瑚礁和沿海红树林有关的海洋生物。在这项研究中，将共生久坐的水母卡西欧豌豆母乳暴露于分析级六嗪酮，以测定其敏感性和暴露于14天的压榨除草剂事件后的恢复潜力，然后恢复相称持续时间。分析了钟的表面积，光合产量（即有效量子产量，EQY），石笋数和黄原虫密度。大多数指标显示，暴露于更高浓度的六嗪酮后会显着降低，当暴露浓度为31μg/ L六嗪酮及以上时，EQY显着降低。相反，与对照动物相比，最高浓度的虫黄藻密度（细胞/ mm2）增加。在暴露期结束时，钟形表面积，EQY和针石计数的EC50分别为176μg/ L，81.96μg/ L和304.3μg/ L。在14天恢复期结束时，所有测量指标的水母都能恢复到相似的起始值，EQY显示恢复期的第7天已恢复。这项研究表明，作为估计年龄的石笋数量不受除草剂的影响。我们得出的结论是，除草剂与C的影响相关的指标令人沮丧。