“In Murden Cove, summertime fills the senses. It inspires the squawks of herons and shrieks of eagles, it ushers away winter clouds to reveal Mt. Ranier towering in the distance. And across tidal flats on gentle breezes, it sends an obnoxious, putrescent stench.Other places on Bainbridge Island can stink, said Brandi Hunt, who lives near the cove, but they don’t stink like this does.On torrid, cloudless days at a low tide, the smell begins. It starts on the mud flats and the silt-covered banks of the Murden Cove stream and it rises in feculent wafts upwards, past Hunt’s house on Moran Road.On the worst days it even reaches the highway, where drivers turning from 305 onto Sportsman Club Road shrivel their noses, roll up their windows and step on the gas. It’s rank, said Mary Terry, who drives past the smell at the head of the cove to reach her house on Manitou Beach Road. You couldn’t pay me to live down there.When the smell starts, efforts to stave it fail, said Bob Coleman, who lives on the beach near the mud flats.It comes in the house, he said, and the first thing you think is, ‘Oooh, did somebody not flush the toilet?’With the recent spate of hot weather, the smell even prompted two letters of inquiry to the Review.Moving here in January this year, we find Bainbridge a lovely place. We do however wonder what that terrible sewage smell is at the corner of Manitou Beach and 305, asked Rolling Bay resident Ed Smith. There must be a way to eliminate this. If there is a sewage leak or spill is must be a health hazard.Although the bouquet of the implacable reek conjures images of a massive sanitation problem, University of Washington oceanography professor Alan Devol says the miscreants behind the malodor most likely aren’t doing anything illegal. They aren’t even human.They are just normal bacteria, he said, doing probably what they have been doing for a millennium.The microscopic organisms live below the surface of the mudflats and eat dead organic matter. When they convert the matter into energy, they produce hydrogen sulfide gas – the same gas that emanates from rotten eggs.The notion that the smell doesn’t come from sewage pipes seems logical to Murden Cove resident Steve Trick.We’ve been here 26 years and that smell’s been here ever since we’ve been here, he said. We just figured it’s part of life.The city has looked into the odor. But in the case of a sewage leak, assistant city engineer Ross Hathaway said, Usually you pick up the smell of water detergent, and I haven’t smelled that. Stinky bacteria is a more likely culprit, Devol said, because it only lives in environments with very low levels of oxygen, and the Murden Cove mudflats provide an ideal home. Unlike sand, thick mud sediments are not highly porous and do not allow water carrying oxygen from above to pass through.Yet while these bacteria do not need oxygen to function, they do need organic matter like plant debris and, ideally, warm temperatures. Since both of these elements are in high supply during the summer, the bacteria produce more energy, multiply and make a bigger stink.The stench also grows more powerful in the summer because gasses released in warmer air move faster and spread more quickly.It’s like cheese, Devol said. You put your cheese out, it warms up, and it smells stronger.On a sultry day, mudflats can smell worse than aged Gorgonzola, but when the ghastly little bacteria break bits of leaves, algae and wood into gasses, they serve an important ecological role, Devol said.One of the bacteria’s functions is to clean up all the dead organic matter, he said, so the earth doesn’t turn into a big trash pile.For Bob Coleman, knowing that the smell comes from a natural ecological process makes it bearable.You never get used to it, he said, but at least you know what it is.But some lifelong residents hardly give the odor a second thought. I can’t smell anything because I’ve been here a long time, said 8-year-old Erika Hunt as she tromped through the mud in her rubber boots Wednesday.Although Coleman isn’t as happily acclimated to the smell, he said he has no plans to move from his multi-story home overlooking the estuary, Puget Sound, and the skyline of Seattle.It smells better than the city, with all of the smog and exhaust over there, Coleman said. I’ll take this here.”