It sounds like the plot of a summer horror flick: malignant cells floating in the sea, ferrying infectious cancer everywhere they go. The story is all too true, say scientists who’ve made a discovery they call “beyond surprising.” Outbreaks of leukemia that have devastated populations of soft-shell clams (Mya arenaria) along the east coast of the United States and Canada are the result of cancerous tumor cells making their way from one clam to another. The finding was reported in 2015 in the journal Cell. 

Dybas, C.L. 2016. Ripple marks—The story behind the story. Oceanography 29(2):12–13, https://doi.org/10.5670/oceanog.2016.28.

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.