At the rate it's going, that seaweed will consume every coast line east and west of the Atlantic on a permanent basis. It's already 10 million tonnes and growing, and it's useless as a material due to the high levels of salt, heavy metals and arsenic, it would just poison plant life and the water supply. The usual bullshit story about climate change and sewage being the cause, I'd be willing to bet it's more likely a chemical spill or some intentional human intervention that started all this in 2010/2011 and it's run amok.