I was given the opportunity to present my work at The Amerikas Colloquium at Ludwigs-Maximilians-Universität München. I asked who has responsibility for Sargassum, how it is ascribed, and how it is dispersed among several actors?to ask about responsibility for Sargassum. The root cause of its massive arrivals cannot be clearly assigned to a specific actor or group of actors, and different people concerned have varying ideas about what should (not) be done with the algae. Against the backdrop of my ethnographic fieldwork, I demonstrated how questions of responsibility become increasingly complex in the Anthropocene, and Sargassum is a prime example to illustrate how responsibility is negotiated, ascribed, and (not) assumed.