Our carbon dioxide emissions are making the oceans more acidic. As we pump carbon dioxide into the atmosphere, a portion dissolves into the world’s oceans. Once there, the carbon dioxide goes through a series of chemical changes that have an acidifying effect on seawater.
Trees absorb carbon dioxide from the air and through photosynthesis. Underwater vegetation, like seagrass meadows and kelp forests, photosynthesize like their land-based relatives. In the process, this aquatic vegetation removes some of the excess carbon dioxide in the surrounding seawater that causes ocean acidification.
Read More https://www.forbes.com/sites/allenelizabeth/2021/04/12/scientists-find-underwater-plants-can-combat-ocean-acidification/?sh=6c9c6e6f5875