The distribution of global photosynthesis primarily across tropical rainforests on land and phytoplankton in the oceans is a foundational and widely established geographical and ecological fact that does not require citation.
The claim states that global photosynthesis is primarily distributed across tropical rainforests and oceanic phytoplankton. This is a standard, fundamental textbook fact about the Earth's primary productivity (terrestrial tropical forests dominating land productivity and marine phytoplankton driving oceanic carbon fixation). It falls under common knowledge, so no citations are needed and no papers are attached as direct evidence.