Environmental impact research on the 2nd carbon removal approach (increasing the capacity of seawater to hold carbon) covers a range of individual species and communities from bacteria to fish. Organism responses vary between species, location, and season, with a mixture of negative, neutral and positive responses recorded.
Researchers are carefully increasing the scale of experiments, moving from the laboratory to the marine environment, which is crucial for understanding the real-life impacts. However, more research is particularly needed to understand how organisms respond at time scales longer than than two weeks, which becomes difficult in the lab - the Weymouth facility could play a very important role here.
A collection of research papers on this topic can be found here.