ScienceMedusa of the deep: Freshwater jellyfish To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 videoScience09/14/2018September 14, 2018Freshwater jellyfish first appeared in Europe more than a century ago. But the invasive species that's native to China is still mostly a mystery. Scientists are now investigating what their rising numbers mean for freshwater ecosystems.https://p.dw.com/p/34sL2Advertisement