It is difficult to determine the exact effect on producer productivity if more coral moved into the ocean system without more information about the specific ecosystem and the role of coral in the food web. However, in general, coral can serve as a primary producer, meaning that it converts sunlight into energy through photosynthesis and serves as a source of food for other organisms in the ecosystem. Therefore, an increase in coral in the ocean system could potentially increase producer productivity by providing additional primary production.
It is worth noting that coral reefs are complex ecosystems and the impact of an increase in coral on producer productivity could vary depending on the specific dynamics of the ecosystem. Factors such as the availability of nutrients, water quality, and the presence of other species in the ecosystem could all affect the productivity of producers.