What effect does the D region of the ionosphere have on lower frequency HF waves in the daytime?

The D region is the lowest layer of the ionosphere, ranging from about 60 to 90 kilometres above the Earth. It is highly ionized during the daytime due to solar radiation but dissipates quickly after sunset. Unlike the higher E and F regions which refract radio waves back to Earth, the dense D region acts like a sponge for lower frequency HF signals (such as those on the 160m and 80m bands). As these long-wavelength signals travel through the D region, they collide frequently with ions and lose their energy. This is why lower frequency signals are severely attenuated or completely absorbed during the day, making daytime long-distance communication difficult on those bands. Distractors suggesting the D region refracts or bends signals out into space are incorrect; refraction of HF signals is primarily the job of the higher F layers.