Mediterranean Institute of Oceanography, Universite de Toulon Aix-Marseille Univ CNRS IRD, Toulon, France.
School of Mathematics and Statistics, UNSW Sydney, Sydney, NSW 2052, Australia; Centre for Marine Science and Innovation Coastal and Regional Oceanography Laboratory, UNSW Sydney, Sydney, NSW 2052, Australia.
Mar Pollut Bull. 2024 Oct;207:116856. doi: 10.1016/j.marpolbul.2024.116856. Epub 2024 Sep 7.
Physalia spp., or Man-of-War, drifts in tropical and subtropical waters, transported by ocean surface conditions. Its unique drifting behavior, influenced by dimorphism (left or right-handedness), complicates stranding predictions. Specifically, the quantification of the influence of the wind on Physalia spp. movements remains an open question, although essential for accurate Lagrangian tracking models. We investigated the wind effect on Physalia spp. by testing 3D-printed replicas in a controlled wind flume. Our findings reveal that under weak winds, left- and right-handed specimens drift symmetrically apart, aligning with strandings observed near Sydney, Australia. As wind speed rises, the drift angle decreases exponentially from approximately 40°, eventually stabilizing near a downwind direction in high winds. On average, the drift speed is 1.7 % of the wind speed. Variations in body shape impact drift angles and stability, adding stochasticity to paths. The proposed empirical relationship might advance knowledge of Physalia spp. sources, distribution and pathways.
僧帽水母属（Physalia spp.）或葡萄牙战舰，随海洋表面条件漂流于热带和亚热带水域。其独特的漂流行为受二态性（左旋或右旋）影响，增加了搁浅预测的复杂性。具体来说，尽管对准确的拉格朗日追踪模型至关重要，但量化风对僧帽水母属运动的影响仍是一个悬而未决的问题。我们通过在受控风洞中测试 3D 打印复制品，研究了风对僧帽水母属的影响。我们的研究结果表明，在微风条件下，左旋和右旋标本对称地漂移分开，与在澳大利亚悉尼附近观察到的搁浅情况一致。随着风速的增加，漂移角度呈指数下降，最终在强风下稳定在顺风方向附近。平均而言，漂移速度是风速的 1.7%。体型的变化会影响漂移角度和稳定性，为路径增加随机性。所提出的经验关系可能会推进对僧帽水母属来源、分布和路径的认识。
