Probably algae. Land only slightly beats the ocean, like a 53-47 split or something, and trees are only part of the primary production on land: https://en.wiki

Probably algae. Land only slightly beats the ocean, like a 53-47 split or something, and trees are only part of the primary production on land: https://en.wikipedia.org/wiki/Primary_production https://en.wikipedia.org/wiki/Primary_production This is also why you sometimes see startups pumping green goo through plastic pipes for home-scale solar biofuel systems.