So, the water is 33 to 34 degrees and is windy, wavy, while the air temp is maybe 13-degrees and you wonder why did the water become ice within the water aerator and stop the movement of the small blue plastic propeller?
Is because the 110-volt electric line is copper and it conducts enough cold temperature down to the aerator motor so the water will freeze close to the aerator which conducts the cold temp to the water, nearby. ......

..... this is why!