moon lights: how bad for plants?

Walstad recommends some sunlight because she encourages allowing the plants to have emerse growth, that way they can draw CO2 from the air and not be limited by it since no CO2 injection is used in her method. With the emersed growth blocking out a portion of light to the lower tank, sunlight hitting from the side is a welcome addition.
 
Walstad recommends some sunlight because she encourages allowing the plants to have emerse growth, that way they can draw CO2 from the air and not be limited by it since no CO2 injection is used in her method. With the emersed growth blocking out a portion of light to the lower tank, sunlight hitting from the side is a welcome addition.

Of course she also advocates floating plants for blocking light. She goes so far as to say that most aquatic plants are, by nature, shade plants and will still thrive if there is a cover of floating plants. I would like to see more detail and research around this though.
 
AquariaCentral.com