[kuhewa]

I'm confident there's a lot more life in the oceans than you are imagining.

The majority of animal biomass is in the oceans. the reason for the massive 80x disparity is the study cited by that reference was doing a census based on weight of carbon, and that figure is dominated by largely metabolically inert wood.

By biomass, primary producers in the oceans are indeed much lower, but energetic turnover of phytoplankton is very efficient.. imagine that anywhere the water is greenish it is full of photosynthesizers (and everywhere it is crystal clear as well).

In terms of biomass of non-plants, note that pelagic fish are so hyperabundant that ships with sonar thought they were the seafloor wikipedia.org/wiki/Deep_scattering_layer