Aquatic plants and animals in ponds can survive in water even when the temperature at the surface of the pond drops below the freezing point of water?

Yes, because water actually expands as it cools. This means ice is less dense than water - ice floats. So the ice will form a protective layer on top of the pond, keeping it insulated so that the water at the bottom can often be a few degrees warmer than ice (at around 4 degrees C). When this is the case, coldwater aquatic life can survive the winter under the ice.