Deerfield, IL (Aug. 3, 2011) An examination of the world's largest river basins found nutrient-rich and powerful river discharges led to spikes in the blooms of plankton associated with cholera outbreaks. These increased discharges often occur at times of increased temperature in coastal water, suggesting that predicting global warming's potential temperature effect on cholera will be more complicated than first thought, according to a new study published today in the American Journal of Tropical Medicine and Hygiene.
The findings by the authors will help give public health authorities another critical clue toward predicting future outbreaks of cholera based on climatic and environmental models in the hopes of preventing the spread of the deadly and highly infectious disease that currently plagues Haiti and several other countries.
The study began in the Bay of Bengal where researchers aimed to solve a mystery: When sea temperatures rise, phytoplanktonmicroscopic plants that live in the ocean and provide a food source for zooplankton, with which cholera bacteria are associateddecrease. So why had past studies found sea temperatures rising and numbers of phytoplankton also increasing? The authors analyzed twelve years of data, including images from NASA satellites, and pinpointed the large flows from the Ganges, Brahmaputra, and Meghna rivers, carrying nutrients from soil, as the cause of a bloom of phytoplankton. This is followed by zooplankton blooms and thus contributes to outbreaks of cholera.
"We weren't satisfied with just this result, so we then went to test this finding in other placesthe Orinoco (in South America), the Congo, and the Amazon river basins, and we found the same thing: The positive relationship between phytoplankton blooms and ocean temperature is related to large river discharges," said Shafiqul Islam, PhD, the lead investigator of the study and a professor in the Department of Civil and Environment
|Contact: Bridget DeSimone|