You don’t have to worry about shark attacks while swimming in Iowa — but there are some much smaller organisms to look out for in some lakes. Eric O’Brien of the Iowa Department of Natural Resources says Beed’s Lake in Franklin County, Backbone Beach in Delaware County and Emerson Bay in Dickinson County all have bacteria warnings posted this weekend. He says advisories are posted for two different reasons. Backbone and Beed’s Lake beach both were posted for one-time high levels of bacteria, while Emerson Bay beach was posted for having high levels over the last month. O’Brien says the D-N-R has posted a swimming advisory at all three.He says the D-N-R doesn’t close beaches, they post the advisories that state the risks involved in going into the waters. He says they advise people to wash their hands after swimming, to avoid swallowing the water. He says they also advise that you avoid the water if you have open cuts or wounds. O’Brien says very young or very old people are more susceptible to problems as they may have trouble keeping from swallowing the water. O’Brien says three beaches posted is about average this year. He says it’s been a fairly typical year. He says the first part of the year was dry, but as there has been more rain, more stuff has washed into the lakes and caused the bacteria numbers to go up. O’Brien says they removed the swimming advisories this week at Clear Lake in Cerro Gordo County, Rock Creek in Jasper County and Black Hawk in Sac County after their bacteria levels dropped in the latest round of testing. For a complete look at the beach testing results, surf to:www.iowadnr.com and look for the beach monitoring link.