I recently talked to my brother in Florida who told me of the horrific algae bloom the state is experiencing in there, Georgia and South Carolina. I have a goose pond on my farm that also becomes algae affected in the summer.
When I went online to see what I could do, a site recommended barley straw. I bought some and put it in my pond. It works great. No algae — the straw seems to absorb it.
States would need to be purchase barley straw in huge quantities, obviously, but if they could save wildlife, I think it would be worth the investment.