This week the Ecological Society of America is having their annual meeting, and several papers of entomological interest have been presented. One found that increased pollution in urban streams leads to increased mosquito populations:
“Luis Fernando Chaves, a post-doctoral researcher at Emory University, and his team discovered mosquitoes in abundance in a sewage-contaminated stream in Atlanta, but rarely in a nearby clean stream. They also found that mosquitoes were largest in streams with high levels of organic minerals – in this case, nitrogen and phosphorous – that originated from the sewage treatment plants.”
The issue of sewage runoff is a major one here in Michigan.
Many of our cities use the same pipes for sewer water and storm runoff. This means that in a heavy storm, excess water–with all that sewage too–goes right into the watershed. This usually means the Great Lakes or other bodies of water.
Signs posted warning against swimming because of high fecal bacterial counts are a pretty common sight here. Sadly, because of Michigan’s state budget woes, the annual required report of wastewater release has been suspended, effective April 2009. Right now, there is simply not enough staff to monitor our water safety.
Chaves’ work suggests a double whammy–all those bacteria are wonderful food supplies for the bacteria that feed mosquitoes. And the mosquitoes are bigger, which means they can live longer–and have a better shot at transmitting a mosquito-borne disease, of which there are many.
You can read some research about storm runoff closer to home in the Journal of Great Lakes Research–here’s a couple of representative papers:
McLellan, S., Hollis, E., Depas, M., Van Dyke, M., Harris, J., & Scopel, C. (2007). Distribution and Fate of Escherichia coli in Lake Michigan Following Contamination with Urban Stormwater and Combined Sewer Overflows Journal of Great Lakes Research, 33 (3) DOI: 10.3394/0380-1330(2007)33[566:DAFOEC]2.0.CO;2
Tracie M. Jenkins, Troy M. Scott, Mechelle R. Morgan and Joan B. Rose (2005). Occurrence of Alternative Fecal Indicators and Enteric Viruses in Michigan Rivers Journal of Great Lakes Research, 31 (1), 22-31 : doi:10.1016/S0380-1330(05)70235-5
Great Lakes Assessment of Urban development and Water Quality