Researchers have found evidence that "marine snow" -- aggregates of organic material floating in water bodies -- may act as microscopic, island-like refuges for pathogens, or disease-causing organisms. This detritus may skew water sampling procedures and mathematical models used to predict the transmission of waterborne diseases to humans.
The scientists responsible for these findings, funded by a National Science Foundation (NSF)/National Institutes of Health (NIH) Ecology of Infectious Diseases (EID) grant, published their results this week.
The findings are the first to compare the existence of pathogens on marine snow with the way insects, amphibians and other creatures establish homes and persist on remote islands in the oceans.
Theories in island biogeography -- the study of the factors that affect species richness on islands -- also apply to microscopic drifting aggregates, according to Maille Lyons, a scientist at Old Dominion University (ODU) and lead author of the paper, with ODU co-authors Fred Dobbs and Holly Gaff. Other authors are J. Evan Ward of the University of Connecticut; Randall Hicks of the University of Minnesota, Duluth; and John Drake of the University of Georgia.
"These predictions help explain whether and for how long bacteria can thrive on an individual aggregate," said Lyons, "and the relationship between the size of the aggregate and the diversity of species found on it."
"This study shows that theory developed for the 'macroscopic' world applies equally to the microscopic one," said Sam Scheiner, program director in NSF's Division of Environmental Biology, which co-funds the EID program with NSF's Directorate for Geosciences. "It allows scientists to link the small to the large, and to provide predictive tools for understanding disease transmission."
Aggregates are made up of small bits of detritus and other component -- some of which are living organisms -- that usually aren't visible to the naked eye. When these tiny components come in contact with each other, they clump together.
