How is it that the open ocean produces the highest net primary productivity of Earth’s ecosystems, yet net primary productivity per square meter is relatively low? A) Oceans contain greater concentrations of nutrients compared to other ecosystems. B) Oceans receive a lesser amount of solar energy per unit area. C) Oceans have the largest area of all the ecosystems on Earth. D) Ocean ecosystems have less species diversity. E) Oceanic producers are generally much smaller than oceanic consumers.