The American west has had record-breaking burns in recent years, blanketing cities in dangerous amounts of smoke and sending haze across the continent to the east coast. For smoke’s clearly apparent effects in the sky, new research finds it changed the ecology of Castle Lake, a freshwater lake in California, in 2018. … Smoke can alter a lake’s temperature and primary production. It can even change where fish are. During a particularly smoky period, rainbow trout that regularly turn up in shallow water sampling were gone.