718655fb_at_Conundrum__Mackinac_Center___3
[0] Deoxygenation [1] Inert gases or bacteria displace oxygen in ballast water. [2] Non-toxic. Prevents hull corrosion. Effective on fresh water and salt water. [3] 
Expensive. Requires specialized crew and equipment. Potentially ineffective on some species in cyst stages and anaerobic bacteria.
Great Lakes, Great Conundrum [Mackinac Center]
3