The researcher Ander Urrutia (photo), of the UPV/EHU’s Cell Biology in Environmental Toxicology research group and Animal Pathology at CEFAS/OIE, is exploring “the great hidden diversity of unicellular parasitic organisms in the intertidal zone in coastal ecosystems of temperate climates, with the aim of trying to see where they are found, what their ecology is like, how they behave, etc.” Environmental DNA (eDNA) is one of the techniques used to achieve this goal: it is a technique that involves “extracting the DNA contained in either an organic or environmental matrix, for example in an organism or in previously filtered seawater samples.” In particular, Urrutia focused on organisms that parasitize invertebrates: "There are a great many unidentified parasites; we find new DNA sequences and infer their behaviour based on their genetic similarity to other parasites, but we don't really know what they are.”