I was once told that during the summer you could expect the water in the neighbouring carp lake to be constantly cloudy. Carp are bottom feeder and churn up the mud on the bottom of the lake. However, in winter, you would expect the water in the neighbouring carp lake to clear. The fish become dormant then and reduce or stop feeding allowing the water to clear.
This hadn't been true for our lake. It seemed to get cloudier as all the vegetation died back and disappeared from the surface of the water. Looking out of our bedroom this morning I realised that I could see the beginnings of the under water "cabbage leaves" that showed that growth had restarted.