Harmful algal blooms (HABs) in coastal waters will likely continue due to human activity releasing excess nitrogen (N) and phosphorus (P) and global warming increasing ocean temperatures. Near China, three large marine ecosystems (LMEs) bordering China (Yellow Sea/Bohai Sea, East China Sea, and South China Sea) suffer from HABs of various types depending on the NP ratio. In the Caribbean, Sargassum spp. blooms exacerbated by climate change and agricultural runoff are inundating Caribbean beaches, emitting toxic fumes and greenhouse gases through decomposition. HABs negatively impact tourism, artisanal fishing, shore-based industry, human health, standards-of-living, coastal ecology, and the global climate. Barriers, collection machinery, and valorization have been unable to provide sufficient, sustainable, or widespread relief, and onshore economic interests currently outweigh offshore interests. On the other hand, considering philosophy of Taiji, HABs are acting to absorb excess nutrients and CO2 and thus a goal should be carbon negative harvesting and sequestering. A case study will be used where a Sargassum management system is shown to be carbon negative and economically scalable across the Caribbean. Littoral Collection Modules (LCMs) have been created which can be attached to artisanal fishing boats. LCMs collect Sargassum in nets which are brought to a barge which is towed to the deep ocean where Sargassum is pumped to ~150–200 m depth. At this depth its buoyancy sacs collapse and it continues sinking, resulting in Sargassum Ocean Sequestration of Carbon, “SOS Carbon”. Costing and negative emissions calculations for this system show cleanup costs <$1/m3 and emissions reduction potential up to 1.356 → 3.029 tCO2e/dmt Sargassum. By establishing a negative emissions industry that builds resilience against HABs and employing local fishermen to operate LCMs achieves equitable sustainable socioeconomic goals.