By Steven Wilhelm, University of Tennessee, and Joshua Weitz, University of Maryland Virus. The word evokes images of illness and fears of outbreaks. Yet, in the oceans, not all viruses are bad news. Some play a helpful, even critical, role in sustaining marine life. In a new study, we and an international team of scientists examined the behavior of marine viruses in a large band of oxygen-rich water just under the surface of the Atlantic Ocean.