From what I get, yeah, there are several projects that try to use use seaweed on the open ocean to sequester CO2. [1] The yield seems to be mediocre though [2

From what I get, yeah, there are several projects that try to use use seaweed on the open ocean to sequester CO2. [1] The yield seems to be mediocre though [2, 3]. For all seaweed that washes up on the shore, the effect reverses: It rots and releases CO2 and methane into the atmosphere. [4] So if it's a negative feedback loop, then a very weak one, if at all: CO2 emissions cause increased seaweed growth, but increased seaweed coverage doesn't meaningfully reduce greenhouse gas concentrations and in fact can even increase them. [1] https://www.globenewswire.com/news-release/2022/06/09/2459357/0/en/Groundbreaking-project-to-convert-Sargassum-seaweed-into-ethanol-for-use-in-plastics-C-Cause-selected-for-German-Government-s-Disruptive-Innovation-grant.html https://www.globenewswire.com/news-release/2022/06/09/245935... [2] https://www.sciencedirect.com/science/article/abs/pii/S0048969721018696 https://www.sciencedirect.com/science/article/abs/pii/S00489... [3] https://www.nature.com/articles/s41467-021-22837-2 https://www.nature.com/articles/s41467-021-22837-2 [4] https://nsuworks.nova.edu/hcas_etd_all/113/ https://nsuworks.nova.edu/hcas_etd_all/113/