Yeah, I’ve found a few that are really exciting approaches being tried.
There is what Brian Von Herzen is calling Marine Permaculture that uses, wave or solar to drive very simple pumps in order to circulate colder (more nutrient dense) water into warmer areas and growing macroalgie in that flow. these enable kelp forests in otherwise unscaffolded ocean space. Those forests become ocean ecosystems for trophic levels up to large predatory fish.
There is also what Bren Smith is doing with Green Wave which is more intentionally integrating shellfish and often works closer to shore. Some of the benefits apart from biomass production (generally I’ve seen reported that photosynthesis from macroalgie is 4x higher in kelp than in grasslands on land) is that these 3D farms are helping reduce stormsurges, protecting and cleaning water for costal ecosystems.
Yeah, I think that it would be especially useful to combine composting and biochar from algie due to its super high granularity to begin with as well as biochars possibility of acting as aeration, un-chilating heavy metals and increasing the C/N ratios that algie otherwise might suffer from.
IBI would probably have research connections for gas, oil, char conversion of algie…