Ecology 6th Edition by Charles Krebs

تمرين 1

In discussing the effect of light on primary productivity in the ocean, Nielsen and Jensen (1957, p. 108) state:
It is thus quite likely dial a permanent reduction of the light intensity at the surface (to, e.g., 50 percent of its normal value without the other factors being affected-a rather improbable condition in Nature) in the long run would have very little influence on the organic productivity as measured per surface area.
How could this possibly be true?