Scientists discovered a new black yeast fungus called Phialophora submersa in Spanish river sediments and tested whether it could infect humans. Using laboratory macrophage (immune cell) models, they found that this environmental fungus exhibits pathogenic potential similar to known disease-causing Phialophora species, though at intermediate levels. The fungus showed resistance to some antifungal drugs and displayed strain-dependent ability to survive various stress conditions. This research suggests that environmental fungal species may pose unexpected health risks despite not being able to grow at normal human body temperature.