Did Peeing Swimmers Kill 500 Fish? Phosphates in urine linked to algae bloom By Mary Papenfuss, Newser User Posted May 14, 2012 1:06 AM CDT Updated May 14, 2012 3:00 AM CDT 16 comments Comments Some believe urine is killing the fish in Eichbaum lake in Hamburg. (?EsotericSapience) (Newser) – It's a pisser. Swimmers who pee in a lake could be responsible for the death of 500 fish. Experts believe a significant amount of urine in popular Eichbaum Lake in northern Germany is linked to an algae bloom that poisoned the fish. "Swimmers who urinate in the lake are introducing a lot of phosphate," a spokesman for the Hamburger Angling Association told Bild newspaper. "We're calculating half a liter of urine per swimmer per day." Phosphate contributes to the build-up of blue-green algae. Swimmers are currently barred from the lake because of the algae bloom. But swimming enthusiasts claim anglers are promoting the leaky urine-algae link because they want the swimmers out of the water. Some environmental observers think the problem may be caused in part by ice skaters who wake up the fish during hibernation. The fish can't find enough oxygen then under the ice, and their bodies are only now being found, reports the German Local. Hamburg's Urban Development and Environmental Authority is calling in the local university to test the pee-death theory.